Fact Sheet on Diseases UPSC


  • Antibiotic resistance is one of the biggest threats to global health, food security, and development
  • Antibiotic resistance can affect anyone, of any age, in any
  • Antibiotic resistance occurs naturally, but misuse of antibiotics in humans and animals is accelerating the
  • A growing number of infections – such as pneumonia, tuberculosis, gonorrhoea, and salmonellosis – are becoming harder to treat as the antibiotics used to treat them become less
  • Antibiotic resistance leads to longer hospital stays, higher medical costs and increased
  • The “Global action plan on antimicrobial resistance” has 5 strategic objectives:
    • To improve awareness and understanding of antimicrobial
    • To strengthen surveillance and
    • To reduce the incidence of
    • To optimize the use of antimicrobial
    • To ensure sustainable investment in countering antimicrobial


  • Antimicrobial resistance happens when microorganisms (such as bacteria, fungi, viruses, and parasites) change when they are exposed to antimicrobial drugs (such as antibiotics, antifungals, antivirals, antimalarials, and anthelmintics). Microorganisms that develop antimicrobial resistance are sometimes referred to as “superbugs”.
  • As a result, the medicines become ineffective and infections persist in the body, increasing the risk of spread to others.
  • The Global Antimicrobial Resistance Surveillance System (GLASS)
    • The WHO-supported system supports a standardized approach to the collection, analysis and sharing of data related to antimicrobial resistance at a global level to inform decision-making, drive local, national and regional action.
  • Global Antibiotic Research and Development Partnership (GARDP)
    • A joint initiative of WHO and Drugs for Neglected Diseases initiative (DNDi), GARDP encourages research and development through public-private partnerships. By 2023, the partnership aims to develop and deliver up to four new treatments, through improvement of existing antibiotics and acceleration of the entry of new antibiotic drugs.
  • Interagency Coordination Group on Antimicrobial Resistance (IACG)
    • The United Nations Secretary-General has established IACG to improve coordination between international organizations and to ensure effective global action against this threat to health security. The IACG is co- chaired by the UN Deputy Secretary-General and the Director General of WHO and comprises high level representatives of relevant UN agencies, other international organizations, and individual experts across different sectors.


  • Arsenic is naturally present at high levels in the groundwater of a number of
  • Arsenic is highly toxic in its inorganic
  • Contaminated water used for drinking, food preparation and irrigation of food crops poses the greatest threat to public health from arsenic.
  • Long-term exposure to arsenic from drinking-water and food can cause cancer and skin lesions. It has also been associated with cardiovascular disease and diabetes. In utero and early childhood exposure has been linked to negative impacts on cognitive development and increased deaths in young
  • The most important action in affected communities is the prevention of further exposure to arsenic by provision of a safe water supply.


  • About 125 million people in the world are exposed to asbestos at the
  • All forms of asbestos, including chrysotile, are carcinogenic to
  • Asbestos is a group of naturally occurring fibrous minerals with current or historical commercial usefulness due to their extraordinary tensile strength, poor heat conduction, and relative resistance to chemical For these reasons, asbestos is used for insulation in buildings and as an ingredient in a number of products, such as roofing shingles, water supply lines, and fire blankets, as well as clutches and brake linings, gaskets, and pads for automobiles.
  • The main forms of asbestos are chrysotile (white asbestos) and crocidolite (blue asbestos). Other forms include amosite, anthophylite, tremolite and actinolite.


  • 1 in 160 children has an autism spectrum disorder (ASD).
  • ASDs begin in childhood and tend to persist into adolescence and
  • While some people with ASD can live independently, others have severe disabilities and require life-long care and support.
  • Evidence-based psychosocial interventions, such as behavioural treatment and parent skills training programmes, can reduce difficulties in communication and social behaviour, with a positive impact on wellbeing and quality of life for persons with ASD and their
  • Interventions for people with ASD need to be accompanied by broader actions for making physical, social and attitudinal environments more accessible, inclusive and
  • Worldwide, people with ASD are often subject to stigma, discrimination and human rights violations. Globally, access to services and support for people with ASD is inadequate.


  • Clostridium botulinum is a bacterium that produces dangerous toxins (botulinum toxins) under low- oxygen
  • Botulinum toxins are one of the most lethal substances
  • Botulinum toxins block nerve functions and can lead to respiratory and muscular
  • Human botulism may refer to foodborne botulism, infant botulism, wound botulism, and inhalation botulism or other types of
  • Foodborne botulism, caused by consumption of improperly processed food, is a rare but potentially fatal disease if not diagnosed rapidly and treated with
  • Homemade canned, preserved or fermented foodstuffs are a common source of foodborne botulism and their preparation requires extra caution.


  • Buruli ulcer is a chronic debilitating disease caused by Mycobacterium
  • It often affects the skin and sometimes bone, and can lead to permanent disfigurement and long-term disability.
  • At least 33 countries with tropical, subtropical and temperate climates have reported Buruli ulcer in Africa, South America and Western Pacific regions. In Australia, an increasing number of cases have been reported since 2013.
  • Partial data from 13 countries for 2017 shows 2206 cases compared to 1920 in 2016; Australia and Nigeria reporting most cases.
  • Most patients in Africa are children aged under 15 years and most patients in Australia are
  • The mode of transmission is not known and there is no prevention for the disease.


  • Campylobacter is 1 of 4 key global causes of diarrhoeal diseases. It is considered to be the most common bacterial cause of human gastroenteritis in the
  • Campylobacter infections are generally mild, but can be fatal among very young children, elderly, and immunosuppressed
  • Campylobacter species can be killed by heat and thoroughly cooking
  • To prevent Campylobacter infections, make sure to follow basic food hygiene practices when preparing food.
  • Campylobacter species are widely distributed in most warm-blooded animals. They are prevalent in food animals such as poultry, cattle, pigs, sheep and ostriches; and in pets, including cats and dogs. The bacteria have also been found in
  • The main route of transmission is generally believed to be foodborne, via undercooked meat and meat products, as well as raw or contaminated milk. Contaminated water or ice is also a source of infection. A proportion of cases occur following contact with contaminated water during recreational
  • Campylobacteriosis is a zoonosis, a disease transmitted to humans from animals or animal products. Most often, carcasses or meat are contaminated by Campylobacter from faeces during slaughtering. In animals, Campylobacter seldom causes disease.


  • Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels and they include:
  • coronary heart disease – disease of the blood vessels supplying the heart muscle;
  • cerebrovascular disease – disease of the blood vessels supplying the brain;
  • peripheral arterial disease – disease of blood vessels supplying the arms and legs;
  • rheumatic heart disease – damage to the heart muscle and heart valves from rheumatic fever, caused by streptococcal bacteria;
  • congenital heart disease – malformations of heart structure existing at birth;
  • deep vein thrombosis and pulmonary embolism – blood clots in the leg veins, which can dislodge and move to the heart and


  • About 6 million to 7 million people worldwide, mostly in Latin America, are estimated to be infected with Trypansosoma cruzi, the parasite that causes Chagas
  • Vector-borne transmission occurs in the Americas. The insect vector is a triatomine bug that carries the parasite Trypanosoma cruzi which causes the
  • Chagas disease was once entirely confined to the Region of the Americas – principally Latin America – but has since spread to other
  • Trypanosoma cruzi infection is curable if treatment is initiated soon after
  • In the chronic phase, antiparasitic treatment can also prevent or curb disease
  • Up to 30% of chronically infected people develop cardiac alterations and up to 10% develop digestive, neurological or mixed alterations which may require specific
  • Vector control is the most useful method to prevent Chagas disease in Latin
  • Blood screening is vital to prevent infection through transfusion and organ
  • Diagnosis of infection in pregnant women, their newborns and siblings are
  • In Latin America, T. cruzi parasites are mainly transmitted by contact with faeces/urine of infected blood- sucking triatomine bugs. These bugs, vectors that carry the parasites, typically live in the wall or roof cracks of poorly-constructed homes in rural or suburban
  • Normally they hide during the day and become active at night when they feed on human
  • They usually bite an exposed area of skin such as the face, and the bug defecates close to the bite. The parasites enter the body when the person instinctively smears the bug faeces or urine into the bite, the eyes, the mouth, or into any skin
  • There is no vaccine for Chagas disease.
  • Vector control is the most effective method of prevention in Latin America. Blood screening is necessary to prevent infection through transfusion and organ transplantation.
  • T. cruzi can also be transmitted by:
    • consumption of food contaminated with T. cruzi through, for example, contact with faeces or urine of infected triatomine bugs or marsupials;
    • blood transfusion from infected donors;
    • passage from an infected mother to her newborn during pregnancy or childbirth;
    • organ transplants using organs from infected donors; and
    • laboratory accidents.


  • Chikungunya is a viral disease transmitted to humans by infected It causes fever and severe joint pain. Other symptoms include muscle pain, headache, nausea, fatigue and rash.
  • Joint pain is often debilitating and can vary in
  • The disease shares some clinical signs with dengue and zika, and can be misdiagnosed in areas where they are
  • There is no cure for the disease. Treatment is focused on relieving the
  • The proximity of mosquito breeding sites to human habitation is a significant risk factor for
  • The virus is transmitted from human to human by the bites of infected female mosquitoes. Most commonly, the mosquitoes involved are Aedes aegypti and Aedes albopictus, two species which can also transmit other mosquito- borne viruses, including dengue.
  • These mosquitoes can be found biting throughout daylight hours, though there may be peaks of activity in the early morning and late Both species are found biting outdoors, but Ae. aegypti will also readily feed indoors.


  • Cholera is an acute diarrhoeal disease that can kill within hours if left
  • Researchers have estimated that each year there are 1.3 million to 4.0 million cases of cholera, and 21 000 to 143 000 deaths worldwide due to cholera (1).
  • Most of those infected will have no or mild symptoms, and can be successfully treated with oral rehydration
  • Severe cases will need rapid treatment with intravenous fluids and
  • Provision of safe water and sanitation is critical to control the transmission of cholera and other waterborne
  • Safe oral cholera vaccines should be used in conjunction with improvements in water and sanitation to control cholera outbreaks and for prevention in areas known to be high risk for
  • A global strategy on cholera control with a target to reduce cholera deaths by 90% was launched in
  • The cholera bacterium is usually found in water or food sources that have been contaminated by feces (poop) from a person infected with cholera.
  • Cholera is most likely to be found and spread in places with inadequate water treatment, poor sanitation, and inadequate


  • Chronic obstructive pulmonary disease (COPD) is a progressive lifethreatening lung disease that causes breathlessness (initially with exertion) and predisposes to exacerbations and serious
  • The primary cause of COPD is exposure to tobacco smoke (either active smoking or second- hand smoke).
  • Other risk factors include exposure to indoor and outdoor air pollution and occupational dusts and
  • Exposure to indoor air pollution can affect the unborn child and represent a risk factor for developing COPD later in
  • Some cases of COPD are due to long-term
  • COPD is likely to increase in coming years due to higher smoking prevalence and aging populations in many
  • Many cases of COPD are preventable by avoidance or early cessation of smoking.
  • Hence, it is important that countries adopt the WHO Framework Convention on Tobacco Control (WHO- FCTC) and implement the MPOWER package of measures so that non-smoking becomes the norm globally.
  • COPD is not curable, but treatment can relieve symptoms, improve quality of life and reduce the risk of death.


  • Congenital anomalies can contribute to long-term disability, which may have significant impacts on individuals, families, health-care systems, and
  • The most common, severe congenital anomalies are heart defects, neural tube defects and Down
  • Although congenital anomalies may be the result of one or more genetic, infectious, nutritional or environmental factors, it is often difficult to identify the exact
  • Some congenital anomalies can be prevented. Vaccination, adequate intake of folic acid or iodine through fortification of staple foods or supplementation, and adequate antenatal care are just 3 examples of prevention methods.


  • Coronavirus disease (COVID-19) is an infectious disease caused by a newly discovered coronavirus.
  • Most people infected with the COVID-19 virus will experience mild to moderate respiratory illness and recover without requiring special treatment.
  • The COVID-19 virus spreads primarily through droplets of saliva or discharge from the nose when an infected person coughs or sneezes, so it’s important that you also practice respiratory etiquette (for example, by coughing into a flexed elbow).
  • COVID-19 affects different people in different ways. Most infected people will develop mild to moderate illness and recover without hospitalization.

Most common symptoms:

  • fever.
  • dry cough.
  • tiredness.

Less common symptoms:

  • aches and pains.
  • sore throat.
  • diarrhoea.
  • conjunctivitis.
  • headache.
  • loss of taste or smell.
  • a rash on skin, or discolouration of fingers or toes.

Serious symptoms:

  • difficulty breathing or shortness of breath.
  • chest pain or pressure.
  • loss of speech or movement


  • The Crimean-Congo haemorrhagic fever (CCHF) virus causes severe viral haemorrhagic fever
  • CCHF outbreaks have a case fatality rate of up to 40%.
  • The virus is primarily transmitted to people from ticks and livestock animals. Human-to-human transmission can occur resulting from close contact with the blood, secretions, organs or other bodily fluids of infected
  • CCHF is endemic in Africa, the Balkans, the Middle East and Asia, in countries south of the 50th parallel north.
  • There is no vaccine available for either people or
  • The CCHF virus is transmitted to people either by tick bites or through contact with infected animal blood or tissues during and immediately after
  • The majority of cases have occurred in people involved in the livestock industry, such as agricultural workers, slaughterhouse workers and veterinarians.
  • Human-to-human transmission can occur resulting from close contact with the blood, secretions, organs or other bodily fluids of infected persons.
  • Hospital-acquired infections can also occur due to improper sterilization of medical equipment, reuse of needles and contamination of medical supplies


  • Dementia is a syndrome in which there is deterioration in memory, thinking, behaviour and the ability to perform everyday
  • Although dementia mainly affects older people, it is not a normal part of
  • Worldwide, around 50 million people have dementia, and there are nearly 10 million new cases every year.
  • Alzheimer’s disease is the most common form of dementia and may contribute to 60–70% of
  • Dementia is one of the major causes of disability and dependency among older people
  • Dementia has a physical, psychological, social, and economical impact, not only on people with dementia, but also on their carers, families and society at large.


  • Dengue is a mosquito-borne viral
  • The infection causes flu-like illness, and occasionally develops into a potentially lethal complication called severe
  • The global incidence of dengue has grown dramatically in recent decades. About half of the world’s population is now at
  • Dengue is found in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban
  • Severe dengue is a leading cause of serious illness and death among children in some Asian and Latin American
  • There is no specific treatment for dengue/ severe dengue, but early detection and access to proper medical care lowers fatality rates below 1%.
  • Dengue prevention and control depends on effective vector control
  • A dengue vaccine has been licensed by several National Regulatory Authorities for use in people 9-45 years of age living in endemic
  • The Aedes aegypti mosquito is the primary vector of dengue. The virus is transmitted to humans through the bites of infected female mosquitoes. After virus incubation for 4–10 days, an infected mosquito is capable of transmitting the virus for the rest of its
  • Infected symptomatic or asymptomatic humans are the main carriers and multipliers of the virus, serving as a source of the virus for uninfected mosquitoes. Patients who are already infected with the dengue virus can transmit the infection (for 4–5 days; maximum 12) via Aedesmosquitoes after their first symptoms appear.


  • Diarrhoeal disease is the second leading cause of death in children under five years old. It is both preventable and
  • Diarrhoea is a leading cause of malnutrition in children under five years
  • Diarrhoea is defined as the passage of three or more loose or liquid stools per day (or more frequent passage than is normal for the individual). Frequent passing of formed stools is not diarrhoea, nor is the passing of loose, “pasty” stools by breastfed
  • Diarrhoea is usually a symptom of an infection in the intestinal tract, which can be caused by a variety of bacterial, viral and parasitic organisms. Infection is spread through contaminated food or drinking- water, or from person-to-person as a result of poor


  • Dioxins are a group of chemically-related compounds that are persistent environmental pollutants (POPs).
  • Dioxins are found throughout the world in the environment and they accumulate in the food chain, mainly in the fatty tissue of
  • More than 90% of human exposure is through food, mainly meat and dairy products, fish and shellfish. Many national authorities have programmes in place to monitor the food
  • Dioxins are highly toxic and can cause reproductive and developmental problems, damage the immune system, interfere with hormones and also cause
  • Due to the omnipresence of dioxins, all people have background exposure, which is not expected to affect human However, due to the highly toxic potential, efforts need to be undertaken to reduce current background exposure.
  • Prevention or reduction of human exposure is best done via source-directed measures, e. strict control of industrial processes to reduce formation of dioxins.


  • Dracunculiasis is a crippling parasitic disease on the verge of eradication, with only 30 human cases reported in
  • The disease is usually transmitted when people who have little or no access to improved drinking water sources swallow stagnant water contaminated with parasite-infected water-fleas (Cyclops) that carry infective guinea-worm larvae.
  • About a year after infection, a painful blister forms – 90% of the time on the lower leg – and one or more worms emerge accompanied by a burning
  • To soothe the burning pain, patients often immerse the infected part of the body in
  • The worm(s) then releases thousands of larvae (baby worms) into the water. These larvae reach the infective stage after being ingested by tiny crustaceans or copepods, also called water fleas.


  • Escherichia coli (E. coli) is a bacteria that is commonly found in the lower intestine of warm-blooded organisms. Most E.coli strains are harmless, but some can cause serious food
  • Shiga toxin-producing E. coli (STEC) is a bacterium that can cause severe foodborne
  • Primary sources of STEC outbreaks are raw or undercooked ground meat products, raw milk, and faecal contamination of
  • In most cases, the illness is self-limiting, but it may lead to a life-threatening disease including haemolytic uraemic syndrome (HUS), especially in young children and the
  • STEC is heat-sensitive. In preparing food at home, be sure to follow basic food hygiene practices such as “cook thoroughly”.
  • Following the WHO “Five keys to safer food” is a key measure to prevent infections with foodborne pathogens such as
  • Most available information on STEC relates to serotype O157:H7, since it is easily differentiated biochemically from other E. coli strains. The reservoir of this pathogen appears to be mainly cattle. In addition, other ruminants such as sheep, goats, deer are considered significant reservoirs, while other mammals (such as pigs, horses, rabbits, dogs, and cats) and birds (such as chickens and turkeys) have been found
  • coli O157:H7 is transmitted to humans primarily through consumption of contaminated foods, such as raw or undercooked ground meat products and raw milk.
  • Faecal contamination of water and other foods, as well as cross-contamination during food preparation (with beef and other meat products, contaminated surfaces and kitchen utensils), will also lead to infection.
  • Examples of foods implicated in outbreaks of E. coli O157:H7 include undercooked hamburgers, dried cured salami, unpasteurized fresh-pressed apple cider, yogurt, and cheese made from raw milk.


  • Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness in
  • The virus is transmitted to people from wild animals and spreads in the human population through human-to-human
  • It is thought that fruit bats of the Pteropodidae family are natural Ebola virus Ebola is introduced into the human population through close contact with the blood, secretions, organs or other bodily fluids of infected animals such as chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest.
  • Ebola then spreads through human-to-human transmission via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these
  • More surveillance data and research are needed on the risks of sexual transmission, and particularly on the prevalence of viable and transmissible virus in semen over time.


  • Human echinococcosis is a parasitic disease caused by tapeworms of the genus
  • The two most important forms of the disease in humans are cystic echinococcosis (hydatidosis) and alveolar
  • Humans are infected through ingestion of parasite eggs in contaminated food, water or soil, or through direct contact with animal
  • Echinococcosis is often expensive and complicated to treat, and may require extensive surgery and/or prolonged drug
  • Prevention programmes focus on deworming of dogs and sheep, which are the definitive hosts. In the case of cystic echinococcosis, control measures also include improved food inspection, slaughterhouse hygiene, and public education campaigns. Vaccination of lambs is currently being evaluated as an additional
  • A number of herbivorous and omnivorous animals act as intermediate hosts of Echinococcus. They become infected by ingesting the parasite eggs in contaminated food and water, and the parasite then develops into larval stages in the
  • Carnivores act as definitive hosts for the parasite, and host the mature tapeworm in their They are infected through the consumption of viscera of intermediate hosts that harbour the parasite.
  • Humans act as so-called accidental intermediate hosts in the sense that they acquire infection in the same way as other intermediate hosts, but are not involved in transmitting the infection to the definitive host.
  • Several distinct genotypes of E. granulosus are recognised, some having distinct intermediate host preferences. Some genotypes are considered species distinct from E. granulosus. Not all genotypes cause infections in humans. The genotype causing the great majority of cystic echinococcosis infections in humans is principally maintained in a dog–sheep–dog cycle, yet several other domestic animals may also be involved, including goats, swine, cattle, camels and and yaks.


  • Epilepsy is a chronic disorder of the brain that affects people of all
  • Approximately 50 million people worldwide have epilepsy, making it one of the most common neurological diseases
  • Nearly 80% of the people with epilepsy live in low- and middle-income
  • People with epilepsy respond to treatment approximately 70% of the
  • About three fourths of people with epilepsy living in low- and middle- income countries do not get the treatment they
  • In many parts of the world, people with epilepsy and their families suffer from stigma and
  • Epilepsy is not contagious. The most common type of epilepsy, which affects 6 out of 10 people with the disorder, is called idiopathic epilepsy and has no identifiable
  • Epilepsy with a known cause is called secondary epilepsy, or symptomatic epilepsy.


  • Foodborne trematodiases cause 2 million life years lost to disability and death worldwide every
  • People become infected by eating raw fish, crustaceans or vegetables that harbour the parasite
  • Foodborne trematodiases are most prevalent in East Asia and South
  • Foodborne trematodiases result in severe liver and lung
  • Safe and efficacious medicines are available to prevent and treat foodborne
  • Prevention and management of food-borne trematodes requires cross-sectoral collaboration on the human-animal and ecosystems interface.
  • Foodborne trematodiases are zoonoses, e. they are naturally transmissible from vertebrate animals to people and vice versa. Direct transmission is however not possible, as the relevant causative parasites become infective only after having completed complex life-cycles that usually involve stages in intermediate, non-human hosts.


Disease Infectious agent Acquired through consumption of Natural final hosts of the infection
Clonorchiasis Clonorchis sinensis Fish Dogs and other fish-eating carnivores
Opisthorchiasis Opisthorchis viverrini,
O. felineus
Fish Cats and other fish-eating carnivores
Fascioliasis Fasciola hepatica,
F. gigantica
Aquatic vegetables Sheep, cattle and other herbivores
Paragonimiasis Paragonimus spp. Crustaceans (crabs and crayfish) Cats, dogs and other crustacean-eating carnivores


  • Guillain-Barré syndrome (GBS) is a rare condition in which a person’s immune system attacks the peripheral
  • People of all ages can be affected, but it is more common in adults and in
  • Most people recover fully from even the most severe cases of Guillain-Barré
  • Severe cases of Guillain-Barré syndrome are rare, but can result in near-total
  • Guillain-Barré syndrome is potentially life-threatening. People with Guillain-Barré syndrome should be treated and monitored; some may need intensive care. Treatment includes supportive care and some immunological
  • Guillain-Barré syndrome is often preceded by an infection. This could be a bacterial or viral infection. Guillain-Barré syndrome may also be triggered by vaccine administration or
  • In the context of Zika virus infection, unexpected increase in cases of Guillain-Barré syndrome has been described in affected The most likely explanation of available evidence from outbreaks of Zika virus infection and Guillain-Barré syndrome is that Zika virus infection is a trigger of Guillain- Barré syndrome.


  • Hepatitis A is a viral liver disease that can cause mild to severe
  • The hepatitis A virus (HAV) is transmitted through ingestion of contaminated food and water or through direct contact with an infectious
  • Almost everyone recovers fully from hepatitis A with a lifelong immunity. However, a very small proportion of people infected with hepatitis A could die from fulminant
  • The risk of hepatitis A infection is associated with a lack of safe water, and poor sanitation and hygiene (such as dirty hands).
  • Epidemics can be explosive and cause substantial economic
  • A safe and effective vaccine is available to prevent hepatitis
  • Safe water supply, food safety, improved sanitation, hand washing and the hepatitis A vaccine are the most effective ways to combat the
  • The hepatitis A virus is transmitted primarily by the faecal-oral route; that is when an uninfected person ingests food or water that has been contaminated with the faeces of an infected person. In families, this may happen though dirty hands when an infected person prepares food for family members. Waterborne outbreaks, though infrequent, are usually associated with sewage-contaminated or inadequately treated
  • The virus can also be transmitted through close physical contact with an infectious person, although casual contact among people does not spread the virus


  • Hepatitis B is a viral infection that attacks the liver and can cause both acute and chronic
  • The virus is transmitted through contact with the blood or other body fluids of an infected
  • Hepatitis B is an important occupational hazard for health
  • However, it can be prevented by currently available safe and effective
  • The hepatitis B virus can survive outside the body for at least 7 During this time, the virus can still cause infection if it enters the body of a person who is not protected by the vaccine.
  • In highly endemic areas, hepatitis B is most commonly spread from mother to child at birth (perinatal transmission), or through horizontal transmission (exposure to infected blood), especially from an infected child to an uninfected child during the first 5 years of
  • The development of chronic infection is very common in infants infected from their mothers or before the age of 5
  • Hepatitis B is also spread by percutaneous or mucosal exposure to infected blood and various body fluids, as well as through saliva, menstrual, vaginal, and seminal fluids. Sexual transmission of hepatitis B may occur, particularly in unvaccinated men who have sex with men and heterosexual persons with multiple sex partners or contact with sex workers. Infection in adulthood leads to chronic hepatitis in less than 5% of cases.
  • Transmission of the virus may also occur through the reuse of needles and syringes either in health-care settings or among persons who inject drugs.
  • In addition, infection can occur during medical, surgical and dental procedures, through tattooing, or through the use of razors and similar objects that are contaminated with infected blood.


  • Hepatitis C is a liver disease caused by the hepatitis C virus: the virus can cause both acute and chronic hepatitis, ranging in severity from a mild illness lasting a few weeks to a serious, lifelong
  • The hepatitis C virus is a bloodborne virus and the most common modes of infection are through exposure to small quantities of blood. This may happen through injection drug use, unsafe injection practices, unsafe health care, and the transfusion of unscreened blood and blood
  • There is currently no vaccine for hepatitis C; however, research in this area is
  • The hepatitis C virus is a bloodborne virus. It is most commonly transmitted through:
  • injecting drug use through the sharing of injection equipment;
  • the reuse or inadequate sterilization of medical equipment, especially syringes and needles in healthcare settings; and
  • the transfusion of unscreened blood and blood
  • HCV can also be transmitted sexually and can be passed from an infected mother to her baby; however, these modes of transmission are much less
  • Hepatitis C is not spread through breast milk, food, water or by casual contact such as hugging, kissing and sharing food or drinks with an infected person.


  • Hepatitis D virus (HDV) is a ribonucleic acid (RNA) virus that requires hepatitis B virus (HBV) for its replication. HDV infection occurs only simultaneously or as super-infection with
  • The virus is transmitted through contact with the blood or other body fluids of an infected
  • Vertical transmission from mother to child is
  • Approximately 15 million people across the world are chronically coinfected with HDV and HBV (1).
  • Currently there is no effective antiviral treatment for hepatitis
  • Hepatitis D infection can be prevented by hepatitis B
  • The routes of HDV transmission are the same as for HBV: percutaneously or sexually through contact with infected blood or blood
  • Vertical transmission is possible but Vaccination against HBV prevents HDV coinfection, and hence expansion of childhood HBV immunization programmes has resulted in a decline in hepatitis D incidence worldwide.
  • However, in some settings, the increase of hepatitis D prevalence has been observed in people who inject drugs, or as a result of migration from areas where HDV is endemic.


  • Hepatitis E is a liver disease caused by infection with a virus known as hepatitis E virus (HEV).
  • The virus is transmitted via the faecal-oral route, principally via contaminated
  • Hepatitis E is found worldwide, but the prevalence is highest in East and South
  • A vaccine to prevent hepatitis E virus infection has been developed and is licensed in China, but is not yet available
  • The hepatitis E virus is transmitted mainly through the faecal-oral route due to faecal contamination of drinking water. This route accounts for a very large proportion of clinical cases with this disease. The risk factors for hepatitis E are related to poor sanitation, allowing virus excreted in the faeces of infected people to reach drinking water
  • Other routes of transmission have been identified, but appear to account for a much smaller number of clinical cases. These routes of transmission include:
  • ingestion of undercooked meat or meat products derived from infected animals;
  • transfusion of infected blood products; and
  • vertical transmission from a pregnant woman to her
  • The ingestion of raw or uncooked shellfish may be the source of sporadic cases in endemic areas.


  • The herpes simplex virus, or herpes, is categorized into 2 types: herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2).
  • HSV-1 is mainly transmitted by oral-to-oral contact to cause oral herpes (which can include symptoms known as “cold sores”), but can also cause genital
  • HSV-2 is a sexually transmitted infection that causes genital
  • Both HSV-1 and HSV-2 infections are
  • Most oral and genital herpes infections are
  • Symptoms of herpes include painful blisters or ulcers at the site of
  • Herpes infections are most contagious when symptoms are present but can still be transmitted to others in the absence of
  • Infection with HSV-2 increases the risk of acquiring and transmitting HIV
  • HSV-1 is mainly transmitted by oral-to-oral contact to cause oral herpes infection, via contact with the HSV-1 virus in sores, saliva, and surfaces in or around the mouth. However, HSV-1 can also be transmitted to the genital area through oral-genital contact to cause genital
  • HSV-1 can be transmitted from oral or skin surfaces that appear normal and when there are no symptoms present. However, the greatest risk of transmission is when there are active
  • Individuals who already have HSV-1 oral herpes infection are unlikely to be subsequently infected with HSV-1 in the genital
  • In rare circumstances, HSV-1 infection can be transmitted from a mother with genital HSV-1 infection to her infant during delivery.


  • Humans can be infected with avian, swine and other zoonotic influenza viruses, such as avian influenza virus subtypes A(H5N1), A(H7N9), and A(H9N2) and swine influenza virus subtypes A(H1N1), A(H1N2) and A(H3N2).
  • Human infections are primarily acquired through direct contact with infected animals or contaminated environments, these viruses have not acquired the ability of sustained transmission among
  • Avian, swine and other zoonotic influenza virus infections in humans may cause disease ranging from mild upper respiratory tract infection (fever and cough), early sputum production and rapid progression to severe pneumonia, sepsis with shock, acute respiratory distress syndrome and even death. Conjunctivitis, gastrointestinal symptoms, encephalitis and encephalopathy have also been reported to varying degrees depending on
  • The majority of human cases of influenza A (H5N1) and A(H7N9) virus infection have been associated with direct or indirect contact with infected live or dead poultry. Controlling the disease in the animal source is critical to decrease risk to
  • Influenza viruses, with the vast silent reservoir in aquatic birds, are impossible to eradicate. Zoonotic influenza infection in humans will continue to To minimize public health risk, quality surveillance in both animal and human populations, thorough investigation of every human infection and risk-based pandemic planning are essential.


The pathogen

  • There are 4 types of seasonal influenza viruses, types A, B, C and D. Influenza A and B viruses circulate and cause seasonal epidemics of disease.
  • Influenza A viruses are further classified into subtypes according to the combinations of the hemagglutinin (HA) and the neuraminidase (NA), the proteins on the surface of the Currently circulating in humans are subtype A(H1N1) and A(H3N2) influenza viruses. The A(H1N1) is also written as A(H1N1) pdm09 as it caused the pandemic in 2009 and subsequently replaced the seasonal influenza A(H1N1) virus which had circulated prior to 2009. Only influenza type A viruses are known to have caused pandemics.
  • Influenza B viruses are not classified into subtypes, but can be broken down into Currently circulating influenza type B viruses belong to either B/Yamagata or B/Victoria lineage.
  • Influenza C virus is detected less frequently and usually causes mild infections, thus does not present public health importance.
  • Influenza D viruses primarily affect cattle and are not known to infect or cause illness in people.


  • Ionizing radiation is a type of energy released by atoms in the form of electromagnetic waves or
  • People are exposed to natural sources of ionizing radiation, such as in soil, water, and vegetation, as well as in human-made sources, such as x-rays and medical
  • Ionizing radiation has many beneficial applications, including uses in medicine, industry, agriculture and research.
  • As the use of ionizing radiation increases, so does the potential for health hazards if not properly used or
  • Acute health effects such as skin burns or acute radiation syndrome can occur when doses of radiation exceed certain
  • Low doses of ionizing radiation can increase the risk of longer-term effects such as cancer.


  • Japanese encephalitis virus (JEV) is a flavivirus related to dengue, yellow fever and West Nile viruses, and is spread by
  • JEV is the main cause of viral encephalitis in many countries of Asia with an estimated 68 000 clinical cases every
  • Although symptomatic Japanese encephalitis (JE) is rare, the case-fatality rate among those with encephalitis can be as high as 30%. Permanent neurologic or psychiatric sequelae can occur in 30%– 50% of those with
  • 24 countries in the WHO South-East Asia and Western Pacific regions have endemic JEV transmission, exposing more than 3 billion people to risks of
  • There is no cure for the disease. Treatment is focused on relieving severe clinical signs and supporting the patient to overcome the
  • Safe and effective vaccines are available to prevent JE. WHO recommends that JE vaccination be integrated into national immunization schedules in all areas where JE disease is recognized as a public health
  • JEV is transmitted to humans through bites from  infected  mosquitoes  of  the Culex species  (mainly Culex tritaeniorhynchus). Humans, once infected, do not develop sufficient viraemia to infect feeding mosquitoes. The virus exists in a transmission cycle between mosquitoes, pigs and/or water birds (enzootic cycle). The disease is predominantly found in rural and periurban settings, where humans live in closer proximity to these vertebrate
  • In most temperate areas of Asia, JEV is transmitted mainly during the warm season, when large epidemics can occur. In the tropics and subtropics, transmission can occur year-round but often intensifies during the rainy season and pre-harvest period in rice-cultivating regions.


  • Lassa fever is an acute viral haemorrhagic illness of 2-21 days duration that occurs in West
  • The Lassa virus is transmitted to humans via contact with food or household items contaminated with rodent urine or
  • Person-to-person infections and laboratory transmission can also occur, particularly in hospitals lacking adequate infection prevention and control
  • Lassa fever is known to be endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria, but probably exists in other West African countries as
  • The overall case-fatality rate is 1%. Observed case-fatality rate among patients hospitalized with severe cases of Lassa fever is 15%.
  • Early supportive care with rehydration and symptomatic treatment improves
  • Humans usually become infected with Lassa virus from exposure to urine or faeces of infected Mastomys
  • Lassa virus may also be spread between humans through direct contact with the blood, urine, faeces, or other bodily secretions of a person infected with Lassa fever.
  • There is no epidemiological evidence supporting airborne spread between humans. Person-to-person transmission occurs in both community and health-care settings, where the virus may be spread by contaminated medical equipment, such as re-used Sexual transmission of Lassa virus has been reported.
  • Lassa fever occurs in all age groups and both sexes. Persons at greatest risk are those living in rural areas where Mastomys are usually found, especially in communities with poor sanitation or crowded living conditions.
  • Health workers are at risk if caring for Lassa fever patients in the absence of proper barrier nursing and infection prevention and control practices.


  • The bacterium L. pneumophila was first identified in 1977, as the cause of an outbreak of severe pneumonia in a convention centre in the USA in
  • The most common form of transmission of Legionella is inhalation of contaminated aerosols produced in conjunction with water sprays, jets or mists. Infection can also occur by aspiration of contaminated water or ice, particularly in susceptible hospital
  • Legionnaires’ disease has an incubation period of 2 to 10 days (but up to 16 days has been recorded in some outbreaks).
  • Death occurs through progressive pneumonia with respiratory failure and/or shock and multi-organ failure.
  • Untreated Legionnaires’ disease usually worsens during the first
  • The most common form of transmission of Legionella is inhalation of contaminated aerosols.
  • Sources of aerosols that have been linked with transmission of Legionella include air conditioning cooling towers, hot and cold water systems, humidifiers and whirlpool spas. Infection can also occur by aspiration of contaminated water or ice, particularly in susceptible hospital patients, and by exposure of babies during water births. There is no direct human-to-human transmission.


  • There are 3 main forms of leishmaniases – visceral (also known as kala-azar and the most serious form of the disease), cutaneous (the most common), and
  • A neglected tropical disease affecting almost 100 countries including India.
  • Leishmaniasis is caused by the protozoan Leishmania parasites which are transmitted by the bite of infected female phlebotomine
  • The disease affects some of the poorest people on earth, and is associated with malnutrition, population displacement, poor housing, a weak immune system and lack of financial
  • Visceral leishmaniasis, which is commonly known as Kala-azar in India, is fatal in over 95% of the cases, if left untreated.
  • Leishmaniasis is linked to environmental changes such as deforestation, building of dams, irrigation schemes, and urbanization.
  • Leishmania parasites are transmitted through the bites of infected female phlebotomine sandflies.
  • The epidemiology of leishmaniasis depends on the characteristics of the parasite species, the local ecological characteristics of the transmission sites, current and past exposure of the human population to the parasite, and human
  • Some 70 animal species, including humans, have been found as natural reservoir hosts of Leishmania


  • Leprosy is a chronic disease caused by a bacillus, Mycobacterium
  • leprae multiplies slowly and the incubation period of the disease, on average, is 5 years. In some cases, symptoms may occur within 1 year but can also take as long as 20 years to occur.
  • The disease mainly affects the skin, the peripheral nerves, mucosa of the upper respiratory tract, and also the
  • Leprosy is curable with multidrug therapy (MDT).
  • Leprosy is transmitted via droplets, from the nose and mouth, during close and frequent contacts with untreated
  • Untreated, leprosy can cause progressive and permanent damage to the skin, nerves, limbs, and
  • Leprosy is also known as Hansen’s disease. It is a chronic infectious disease caused by Mycobacterium leprae, a rod-shaped bacillus that is an obligate intracellular (only grows inside of certain human and animal cells) bacterium.


  • Lymphatic filariasis impairs the lymphatic system and can lead to the abnormal enlargement of body parts, causing pain, severe disability and social
  • Lymphatic filariasis can be eliminated by stopping the spread of infection through preventive chemotherapy with safe medicine combinations, repeated annually for at least 5
  • Lymphatic filariasis is caused by infection with parasites classified as nematodes (roundworms) of the family Filariodidea. There are 3 types of these thread-like filarial worms:
  • Wuchereria bancrofti, which is responsible for 90% of the cases
  • Brugia malayi, which causes most of the remainder of the cases
  • Brugia timori, which also causes the


  • Malaria is a life-threatening disease caused by parasites that are transmitted to people through the bites of infected female Anopheles mosquitoes. It is preventable and
  • Malaria is caused by Plasmodium parasites. The parasites are spread to people through the bites of infected female Anopheles mosquitoes, called “malaria vectors.” There are 5 parasite species that cause malaria in humans, and 2 of these species – P. falciparum and P. vivax – pose the greatest threat.
  • falciparum is the most prevalent malaria parasite on the African continent. It is responsible for most malaria-related deaths globally.
  • vivax is the dominant malaria parasite in most countries outside of sub-Saharan Africa.ub
  • Malaria is an acute febrile illness. In a non-immune individual, symptoms usually appear 10–15 days after the infective mosquito bite. The first symptoms – fever, headache, and chills– may be mild and difficult to recognize as malaria.
  • In most cases, malaria is transmitted through the bites of female Anopheles
  • There are more than 400 different species of Anopheles mosquito; around 30 are malaria vectors of major importance. All of the important vector species bite between dusk and dawn.
  • The intensity of transmission depends on factors related to the parasite, the vector, the human host, and the
  • Anopheles mosquitoes lay their eggs in water, which hatch into larvae, eventually emerging as adult mosquitoes.
  • The female mosquitoes   seek   a   blood   meal   to   nurture   their      Each   species of Anopheles mosquito has its own preferred aquatic habitat; for example, some prefer small, shallow collections of fresh water, such as puddles and hoof prints, which are abundant during the rainy season in tropical countries.


  • Marburg virus disease (MVD), formerly known as Marburg haemorrhagic fever, is a severe, often fatal illness in
  • Rousettus aegyptiacus, fruit bats of the Pteropodidae family, are considered to be natural hosts of Marburg virus. The Marburg virus is transmitted to people from fruit bats and spreads among humans through human-to-human
  • The Marburg virus causes severe viral haemorrhagic fever in
  • The average MVD case fatality rate is around 50%. Case fatality rates have varied from 24% to 88% in past outbreaks depending on virus strain and case
  • Initially, human MVD infection results from prolonged exposure to mines or caves inhabited by Rousettus bat
  • Marburg spreads through human-to-human transmission via direct contact (through broken skin or mucous membranes) with the blood, secretions, organs or other bodily fluids of infected people, and with surfaces and materials (e.g. bedding, clothing) contaminated with these
  • Health-care workers have frequently been infected while treating patients with suspected or confirmed MVD. This has occurred through close contact with patients when infection control precautions are not strictly Transmission via contaminated injection equipment or through needle-stick injuries is associated with more severe disease, rapid deterioration, and, possibly, a higher fatality rate.
  • Burial ceremonies that involve direct contact with the body of the deceased can also contribute in the transmission of
  • People remain infectious as long as their blood contains the virus.


  • Measles is one of the leading causes of death among young children even though a safe and cost- effective vaccine is
  • Measles vaccination resulted in a 84% drop in measles deaths between 2000 and 2016
  • The highly contagious virus is spread by coughing and sneezing, close personal contact or direct contact with infected nasal or throat
  • The virus remains active and contagious in the air or on infected surfaces for up to 2 hours. It can be transmitted by an infected person from 4 days prior to the onset of the rash to 4 days after the rash erupts.
  • Measles outbreaks can result in epidemics that cause many deaths, especially among young, malnourished children. In countries where measles has been largely eliminated, cases imported from other countries remain an important source of
  • No specific antiviral treatment exists for measles virus.


  • Microcephaly is a condition where a baby is born with a small head or the head stops growing after
  • Microcephaly is a rare condition. One baby in several thousand is born with
  • The most reliable way to assess whether a baby has microcephaly is to measure head circumference 24 hours after birth, compare the value with WHO growth standards, and continue to measure the rate of head growth in early
  • Babies born with microcephaly may develop convulsions and suffer physical and learning disabilities as they grow
  • There are no specific tests to determine if a baby will be born with microcephaly, but ultrasound scans in the third trimester of pregnancy can sometimes identify the
  • There is no specific treatment for microcephaly.


  • Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus (Middle East respiratory syndrome coronavirus, or MERS‐CoV) that was first identified in Saudi Arabia in
  • Coronaviruses are a large family of viruses that can cause diseases ranging from the common cold to Severe Acute Respiratory Syndrome (SARS).
  • Typical MERS symptoms include fever, cough and shortness of breath. Pneumonia is common, but not always present. Gastrointestinal symptoms, including diarrhoea, have also been reported. Some laboratory-confirmed cases of MERS-CoV infection are reported as asymptomatic, meaning that they do not have any clinical symptoms, yet they are positive for MERS following a laboratory Most of these asymptomatic cases have been detected following aggressive contact tracing of a laboratory-confirmed case.
  • Non-human to human transmission: The route of transmission from animals to humans is not fully understood, but dromedary camels are a major reservoir host for MERS-CoV and an animal source of infection in
  • Strains of MERS-CoV that are identical to human strains have been isolated from dromedaries in several countries, including Egypt, Oman, Qatar, and Saudi
  • Human-to-human transmission: The virus does not pass easily from person to person unless there is close contact, such as providing unprotected care to an infected patient.
  • There have been clusters of cases in healthcare facilities, where human-to-human transmission appears to have occurred, especially when infection prevention and control practices are inadequate or inappropriate. Human to human transmission has been limited to date, and has been identified among family members, patients, and health care
  • While the majority of MERS cases have occurred in health care settings, thus far, no sustained human to human transmission has been documented anywhere in the world.


  • Monkeypox is a rare disease that occurs primarily in remote parts of Central and West Africa, near tropical rainforests.
  • The monkeypox virus can cause a fatal illness in humans and, although it is similar to human smallpox which has been eradicated, it is much
  • The monkeypox virus is transmitted to people from various wild animals but has limited secondary spread through human-to-human
  • Typically, case fatality in monkeypox outbreaks has been between 1% and 10%, with most deaths occurring in younger age
  • There is no treatment or vaccine available although prior smallpox vaccination was highly effective in preventing monkeypox as
  • Infection of index cases results from direct contact with the blood, bodily fluids, or cutaneous or mucosal lesions of infected animals.
  • In Africa human infections have been documented through the handling of infected monkeys, Gambian giant rats and squirrels, with rodents being the major reservoir of the virus. Eating inadequately cooked meat of infected animals is a possible risk factor.
  • Secondary, or human-to-human, transmission can result from close contact with infected respiratory tract secretions, skin lesions of an infected person or objects recently contaminated by patient fluids or lesion materials.
  • Transmission occurs primarily via droplet respiratory particles usually requiring prolonged face-to- face contact, which puts household members of active cases at greater risk of infection. Transmission can also occur by inoculation or via the placenta (congenital monkeypox). There is no evidence, to date, that person-to-person transmission alone can sustain monkeypox infections in the human population.


  • Mycetoma is a chronic, progressively destructive infectious disease of the subcutaneous tissues, affecting skin, muscle and
  • Mycetoma can be caused by different species of microorganisms, but almost always by bacteria or fungus.
  • Mycetoma occurs in tropical and subtropical environments characterized by short rainy seasons and prolonged dry seasons that favour the growth of thorny
  • Global burden is not known, but the disease is endemic has been reported from countries in Africa, Asia, Europe and Latin
  • Mycetoma has numerous adverse medical, health and socioeconomic consequences for patients, communities and health services in affected Transmission occurs when the causative organism enters the body through minor trauma or a penetrating injury, commonly thorn pricks. There is a clear association between mycetoma and individuals who walk barefooted and are manual workers.


  • Mycotoxins are naturally occurring toxins produced by certain moulds (fungi) and can be found in
  • The moulds grow on a variety of different crops and foodstuffs including cereals, nuts, spices, dried fruits, apples and coffee beans, often under warm and humid
  • Mycotoxins can cause a variety of adverse health effects and pose a serious health threat to both humans and
  • The adverse health effects of mycotoxins range from acute poisoning to long-term effects such as immune deficiency and cancer.
  • A scientific expert committee jointly convened by WHO and the Food and Agriculture Organization of the United Nations (FAO) – called JECFA – is the international body responsible for evaluating the health risk from natural toxins including mycotoxins.
  • International standards and codes of practice to limit exposure to mycotoxins from certain foods are established by the Codex Alimentarius Commission based on JECFA assessments.


  • Onchocerciasis, commonly known as “river blindness”, is caused by the parasitic worm Onchocerca volvulus.
  • It is transmitted to humans through exposure to repeated bites of infected blackflies of the genus Simulium
  • Symptoms include severe itching, disfiguring skin conditions, and visual impairment, including permanent
  • More than 99% of infected people live in 31 African countries. The disease also exists in some foci in Latin America and
  • Community-directed treatment with ivermectin is the core strategy to eliminate onchocerciasis in In the Americas the strategy is biannual large-scale treatment with ivermectin.


  • Plague is caused by the bacteria Yersinia pestis, a zoonotic bacterium usually found in small mammals and their
  • People infected with Y. pestis often develop symptoms after an incubation period of one to seven
  • There are two main clinical forms of plague infection: bubonic and pneumonic. Bubonic plague is the most common form and is characterized by painful swollen lymph nodes or ‘buboes’.
  • Plague is transmitted between animals and humans by the bite of infected fleas, direct contact with infected tissues, and inhalation of infected respiratory
  • As an animal disease, plague is found in all continents, except Oceania. There is a risk of human plague wherever the presence of plague natural foci (the bacteria, an animal reservoir and a vector) and human population co-exist.
  • There are two main forms of plague infection, depending on the route of infection: bubonic and pneumonic.
  • Bubonic plague is the most common form of plague and is caused by the bite of an infected flea. Plague bacillus, Y. pestis, enters at the bite and travels through the lymphatic system to the nearest lymph node where it replicates itself.
  • The lymph node then becomes inflamed, tense and painful, and is called a ‘bubo’.
  • At advanced stages of the infection the inflamed lymph nodes can turn into open sores filled with pus.
  • Human to human transmission of bubonic plague is rare.
  • Bubonic plague can advance and spread to the lungs, which is the more severe type of plague called pneumonic
  • Pneumonic plague, or lung-based plague, is the most virulent form of plague. Incubation can be as short as 24 hours. Any person with pneumonic plague may transmit the disease via droplets to other humans. Untreated pneumonic plague, if not diagnosed and treated early, can be fatal. However, recovery rates are high if detected and treated in time (within 24 hours of onset of symptoms).


  • Pneumonia can be caused by viruses, bacteria, or
  • Pneumonia can be prevented by immunization, adequate nutrition, and by addressing environmental factors.
  • Pneumonia caused by bacteria can be treated with antibiotics, but only one third of children with pneumonia receive the antibiotics they
  • Pneumonia can be spread in a number of ways. The viruses and bacteria that are commonly found in a child’s nose or throat, can infect the lungs if they are They may also spread via air-borne droplets from a cough or sneeze. In addition, pneumonia may spread through blood, especially during and shortly after birth.


  • Rabies is a vaccine-preventable viral disease which occurs in more than 150 countries and
  • Dogs are the main source of human rabies deaths, contributing up to 99% of all rabies transmissions to humans.
  • Rabies elimination is feasible through vaccination of dogs and prevention of dog
  • Infection causes tens of thousands of deaths every year, mainly in Asia and
  • WHO, the World Organisation for Animal Health (OIE), the Food and Agriculture Organization of the United Nations (FAO) and the Global Alliance for Rabies Control (GARC) have established a global “United Against Rabies” collaboration to provide a common strategy to achieve “Zero human rabies deaths by 2030”
  • People are usually infected following a deep bite or scratch from an animal with rabies, and transmission to humans by rabid dogs accounts for 99% of cases.
  • Africa and Asia have the highest rabies burden in humans and account for 95% of rabies deaths, worldwide.
  • Transmission can also occur when infectious material – usually saliva – comes into direct contact with human mucosa or fresh skin wounds. Human-to-human transmission through bites is theoretically possible but has never been confirmed.
  • Contraction of rabies through inhalation of virus-containing aerosols or through transplantation of infected organs is rare. Contracting rabies through consumption of raw meat or animal-derived tissue has never been confirmed in humans.
  • Post-exposure prophylaxis (PEP) is the immediate treatment of a bite victim after rabies exposure. This prevents virus entry into the central nervous system, which results in imminent death. PEP consists of:
  • extensive washing and local treatment of the wound as soon as possible after exposure;
  • a course of potent and effective rabies vaccine that meets WHO standards; and
  • the administration of rabies immunoglobulin (RIG), if
  • Effective treatment soon after exposure to rabies can prevent the onset of symptoms and death.


  • Rift Valley fever (RVF) is a viral zoonosis that primarily affects animals but can also infect
  • The majority of human infections result from contact with the blood or organs of infected
  • Human infections have also resulted from the bites of infected
  • To date, no human-to-human transmission of RVF virus has been
  • The incubation period (the interval from infection to onset of symptoms) for RVF varies from 2 to 6
  • Outbreaks of RVF in animals can be prevented by a sustained programme of animal
  • The majority of human infections result from direct or indirect contact with the blood or organs of infected animals. The virus can be transmitted to humans through the handling of animal tissue during slaughtering or butchering, assisting with animal births, conducting veterinary procedures, or from the disposal of carcasses or
  • Certain occupational groups such as herders, farmers, slaughterhouse workers, and veterinarians are therefore at higher risk of
  • The virus infects humans through inoculation, for example via a wound from an infected knife or through contact with broken skin, or through inhalation of aerosols produced during the slaughter of infected animals.
  • There is some evidence that humans may become infected with RVF by ingesting the unpasteurized or uncooked milk of infected animals.
  • Human infections have also  resulted  from  the  bites  of  infected  mosquitoes,  most  commonly  the Aedes and Culex mosquitoes and the transmission of RVF virus by hematophagous (blood- feeding) flies is also
  • To date, no human-to-human transmission of RVF has been documented, and no transmission of RVF to health care workers has been reported when standard infection control precautions have been put in place.
  • There has been no evidence of outbreaks of RVF in urban areas.


  • Rubella is a contagious, generally mild viral infection that occurs most often in children and young adults.
  • Rubella is the leading vaccine-preventable cause of birth defects. Rubella infection in pregnant women may cause fetal death or congenital defects known as congenital rubella
  • There is no specific treatment for rubella but the disease is preventable by
  • The rubella virus is transmitted by airborne droplets when infected people sneeze or Humans are the only known host.


  • Salmonella is 1 of 4 key global causes of diarrhoeal
  • Most cases of salmonellosis are mild; however, sometimes it can be life-threatening. The severity of the disease depends on host factors and the serotype of Salmonella.
  • Antimicrobial resistance is a global public health concern and Salmonella is one of the microorganisms in which some resistant serotypes have emerged, affecting the food
  • Basic food hygiene practices, such as “cook thoroughly”, are recommended as a preventive measure against
  • Salmonella bacteria are widely distributed in domestic and wild animals. They are prevalent in food animals such as poultry, pigs, and cattle; and in pets, including cats, dogs, birds, and reptiles such as turtles.
  • Salmonella can pass through the entire food chain from animal feed, primary production, and all the way to households or food-service establishments and
  • Salmonellosis in humans is generally contracted through the consumption of contaminated food of animal origin (mainly eggs, meat, poultry, and milk), although other foods, including green vegetables contaminated by manure, have been implicated in its
  • Person-to-person transmission can also occur through the faecal-oral
  • Human cases also occur where individuals have contact with infected animals, including pets. These infected animals often do not show signs of disease.


  • Schistosomiasis is an acute and chronic disease caused by parasitic
  • People are infected during routine agricultural, domestic, occupational, and recreational activities, which expose them to infested
  • Lack of hygiene and certain play habits of school-aged children such as swimming or fishing in infested water make them especially vulnerable to
  • Schistosomiasis control focuses on reducing disease through periodic, large-scale population treatment with praziquantel; a more comprehensive approach including potable water, adequate sanitation, and snail control would also reduce
  • People become infected when larval forms of the parasite – released by freshwater snails – penetrate the skin during contact with infested
  • Transmission occurs when people suffering from schistosomiasis contaminate freshwater sources with their excreta containing parasite eggs, which hatch in water.


  • Schizophrenia is a chronic and severe mental disorder affecting more than 21 million people
  • Schizophrenia is characterized by distortions in thinking, perception, emotions, language, sense of self and behaviour. Common experiences include hallucinations – hearing voices or seeing things that are not there and delusions – fixed, false
  • Worldwide, schizophrenia is associated with considerable disability and may affect educational and occupational
  • People with schizophrenia are 2-3 times more likely to die early than the general This is often due to preventable physical diseases, such as cardiovascular disease, metabolic disease and infections.
  • Stigma, discrimination and violation of human rights of people with schizophrenia is
  • Schizophrenia is treatable. Treatment with medicines and psychosocial support is
  • Facilitation of assisted living, supported housing and supported employment are effective management strategies for people with schizophrenia.


  • Sepsis arises when the body’s response to an infection injures its own tissues and organs, potentially leading to death or significant
  • The global epidemiological burden of sepsis is difficult to ascertain. It is estimated to affect more than 30 million people worldwide every year, potentially leading to 6 million deaths (1). The burden of sepsis is most likely highest in low- and middle-income
  • Anyone affected by an infection can progress to sepsis conditions but some vulnerable populations such as elderly people, pregnant women, neonates, hospitalized patients, and people with HIV/AIDS, liver cirrhosis, cancer, kidney disease, autoimmune diseases and no spleen, are at higher risk.


  • Soil-transmitted helminth infections are caused by different species of parasitic
  • They are transmitted by eggs present in human faeces, which contaminate the soil in areas where sanitation is
  • Infected children are nutritionally and physically
  • Control is based on periodical deworming to eliminate infecting worms, health education to prevent re-infection, and improved sanitation to reduce soil contamination with infective
  • Safe and effective medicines are available to control
  • Soil-transmitted helminths are transmitted by eggs that are passed in the faeces of infected people. Adult worms live in the intestine where they produce thousands of eggs each day. In areas that lack adequate sanitation, these eggs contaminate the soil. This can happen in several ways:
  • eggs that are attached to vegetables are ingested when the vegetables are not carefully cooked, washed or peeled;
  • eggs are ingested from contaminated water sources;
  • eggs are ingested by children who play in the contaminated soil and then put their hands in their mouths without washing
  • In addition, hookworm eggs hatch in the soil, releasing larvae that mature into a form that can actively penetrate the People become infected with hookworm primarily by walking barefoot on the contaminated soil.
  • There is no direct person-to-person transmission, or infection from fresh faeces, because eggs passed in faeces need about 3 weeks to mature in the soil before they become infective.
  • Since these worms do not multiply in the human host, re-infection occurs only as a result of contact with infective stages in the environment.


  • Taeniasis is an intestinal infection caused by adult
  • Three tapeworm species cause taeniasis in humans, Taenia solium, Taenia saginata and Taenia Only T. solium causes major health problems.
  • solium taeniasis is acquired by humans through the ingestion of tapeworm larval cysts (cysticerci) in undercooked and infected pork.
  • Human tapeworm carriers excrete tapeworm eggs in their faeces and contaminate the environment when they defecate in open
  • Humans can also become infected with T. solium eggs by ingesting contaminated food or water or as a result of poor
  • Ingested solium eggs develop to larvae (called cysticerci) in various organs of the human body. When they enter the central nervous system, they can cause neurological symptons (neurocysticercosis), including epileptic seizures.
  • solium is the cause of 30% of epilepsy cases in many endemic areas where people and roaming pigs live in close proximity.
  • Taeniasis is an intestinal infection caused by 3 species of tapeworm: Taenia solium (pork tapeworm), Taenia saginata (beef tapeworm) and Taenia asiatica.
  • Humans can become infected with T. saginata or asiatica when they consume infected beef meat or pig liver tissue, respectively, which has not been adequately cooked, but taeniasis due to T. saginata or T. asiatica has no major impact on human health. Therefore, this factsheet refers to the transmission and health impacts of T. solium only.
  • solium cysticercosis was added by WHO to the list of major Neglected Tropical Diseases (NTDs) in 2010 with NTD roadmap goals of  making  available  a  validated  strategy  for   control   and   elimination   of T.   solium taeniasis/cysticercosis and those interventions to be scaled up in selected countries by 2020.


  • Tetanus is acquired through infection of a cut or wound with the spores of the bacterium Clostridium tetani, and most cases occur within 14 days of infection. Tetanus cannot be transmitted from person to person.
  • Tetanus can be prevented through immunization with tetanus-toxoid-containing vaccines (TTCV). However, people who recover from tetanus do not have natural immunity and can be infected
  • The majority of reported tetanus cases are birth-associated among newborn babies and mothers who have not been sufficiently vaccinated with
  • The Maternal and Neonatal Tetanus Elimination (MNTE) Initiative was launched by UNICEF, WHO and the United Nations Population Fund (UNFPA) in 1999, revitalizing the goal of MNTE as a public health problem.


  • Trachoma is a disease of the eye caused by infection with the bacterium Chlamydia
  • Blindness from trachoma is
  • Infection spreads through personal contact (via hands, clothes or bedding) and by flies that have been in contact with discharge from the eyes or nose of an infected person. With repeated episodes of infection over many years, the eyelashes may be drawn in so that they rub on the surface of the eye, with pain and discomfort and permanent damage to the
  • The World Health Assembly adopted resolution WHA51.11 in 1998, targeting the global elimination of trachoma as a public health
  • The elimination strategy is encapsulated by the acronym “SAFE”: Surgery for advanced disease, Antibiotics to clear C. trachomatis infection, Facial cleanliness and Environmental improvement to reduce transmission.


  • Sleeping sickness occurs in 36 sub-Saharan Africa countries where there are tsetse flies that transmit the
  • The people most exposed to the tsetse fly and therefore the disease live in rural areas and depend on agriculture, fishing, animal husbandry or
  • Human African trypanosomiasis takes 2 forms, depending on the parasite involved: Trypanosoma brucei gambiense accounts for more than 98% of reported
  • Diagnosis and treatment of the disease is complex and requires specifically skilled staff.


  • Tuberculosis (TB) is one of the top 10 causes of death
  • Multidrug-resistant TB (MDR-TB) remains a public health crisis and a health security Ending the TB epidemic by 2030 is among the health targets of the Sustainable Development Goals.
  • Tuberculosis (TB) is caused by bacteria (Mycobacterium tuberculosis) that most often affect the Tuberculosis is curable and preventable.
  • TB is spread from person to person through the air. When people with lung TB cough, sneeze or spit, they propel the TB germs into the air. A person needs to inhale only a few of these germs to become infected.
  • About one-quarter of the world’s population has latent TB, which means people have been infected by TB bacteria but are not (yet) ill with the disease and cannot transmit the disease.


  • Typhoid fever is a life-threatening infection caused by the bacterium Salmonella Typhi. It is usually spread through contaminated food or
  • Symptoms include prolonged fever, fatigue, headache, nausea, abdominal pain, and constipation or diarrhoea. Some patients may have a rash. Severe cases may lead to serious complications or even death.
  • Typhoid fever can be treated with antibiotics although increasing resistance to different types of antibiotics is making treatment more
  • Two vaccines have been used for many years to prevent typhoid. A new typhoid conjugate vaccine with longer lasting immunity was prequalified by WHO in December
  • In December 2017, WHO prequalified the first conjugate vaccine for typhoid. This new vaccine has longer-lasting immunity than older vaccines, requires fewer doses and can be given to children from the age of 6
  • This vaccine will be prioritized for countries with the highest burden of typhoid disease. This will help reduce the frequent use of antibiotics for typhoid treatment, which will slow the increase in antibiotic resistance in Salmonella Typhi.


  • Vectors are living organisms that can transmit infectious diseases between humans or from animals to humans.
  • Many of these vectors are bloodsucking insects, which ingest disease-producing microorganisms during a blood meal from an infected host (human or animal) and later inject it into a new host during their subsequent blood meal.
  • Mosquitoes are the best-known disease vector. Others include ticks, flies, sandflies, fleas, triatomine bugs and some freshwater aquatic snails.


  • Aedes
    • Chikungunya
    • Dengue fever
    • Lymphatic filariasis
    • Rift Valley fever
    • Yellow fever
    • Zika
  • Anopheles
    • Malaria
    • Lymphatic filariasis
  • Culex
    • Japanese encephalitis
    • Lymphatic filariasis
    • West Nile fever
  • Sandflies
    • Leishmaniasis
    • Sandfly fever (phelebotomus fever)


  • Crimean-Congo haemorrhagic fever
  • Lyme disease
  • Relapsing fever (borreliosis)
  • Rickettsial diseases (spotted fever and Q fever)
  • Tick-borne encephalitis
  • Tularaemia

Triatomine bugs

  • Chagas disease (American trypanosomiasis)

Tsetse flies

  • Sleeping sickness (African trypanosomiasis)


  • Plague (transmitted by fleas from rats to humans)
  • Rickettsiosis

Black flies

  • Onchocerciasis (river blindness)

Aquatic snails

  • Schistosomiasis (bilharziasis)


  • Typhus and louse-borne relapsing fever


  • West Nile virus can cause a fatal neurological disease in
  • However, approximately 80% of people who are infected will not show any
  • West Nile virus is mainly transmitted to people through the bites of infected
  • The virus can cause severe disease and death in
  • Vaccines are available for use in horses but not yet available for
  • Birds are the natural hosts of West Nile
  • Human infection is most often the result of bites from infected Mosquitoes become infected when they feed on infected birds, which circulate the virus in their blood for a few days. The virus eventually gets into the mosquito’s salivary glands. During later blood meals (when mosquitoes bite), the virus may be injected into humans and animals, where it can multiply and possibly cause illness.
  • The virus may also be transmitted through contact with other infected animals, their blood, or other tissues.
  • A very small proportion of human infections have occurred through organ transplant, blood transfusions and breast milk. There is one reported case of transplacental (mother-to-child) WNV
  • To date, no human-to-human transmission of WNV through casual contact has been documented, and no transmission of WNV to health care workers has been reported when standard infection control precautions have been put in place.


  • Yaws is a chronic disfiguring and debilitating childhood infectious disease caused by Treponema pallidum subspecies
  • It is one of the first diseases targeted for eradication by WHO and UNICEF in the 1950s. WHO renewed global efforts to eradicate yaws in
  • The disease affects skin, bone and Humans are currently believed to be the only reservoir, and transmission is from person to person.
  • Yaws is cured with a single oral dose of an inexpensive antibiotic called azithromycin.


  • Yellow fever is an acute viral haemorrhagic disease transmitted by infected The “yellow” in the name refers to the jaundice that affects some patients.
  • Symptoms of yellow fever include fever, headache, jaundice, muscle pain, nausea, vomiting and
  • A small proportion of patients who contract the virus develop severe symptoms and approximately half of those die within 7 to 10
  • The virus is endemic in tropical areas of Africa and Central and South
  • The yellow fever virus is an arbovirus of the flavivirus genus and is transmitted by mosquitoes, belonging to the Aedes and Haemogogus species.
  • The different mosquito species live in different habitats – some breed around houses (domestic), others in the jungle (wild), and some in both habitats (semi-domestic). There are 3 types of transmission cycles:
  • Sylvatic (or jungle) yellow fever: In tropical rainforests, monkeys, which are the primary reservoir of yellow fever, are bitten by wild mosquitoes of the Aedes and Haemogogusspecies, which pass the virus on to other monkeys.
  • Occasionally humans working or travelling in the forest are bitten by infected mosquitoes and develop yellow
  • Intermediate yellow fever: In this type of transmission, semi-domestic mosquitoes (those that breed both in the wild and around households) infect both monkeys and people. Increased contact between people and infected mosquitoes leads to increased transmission and many separate villages in an area can develop outbreaks at the same time.
  • This is the most common type of outbreak in
  • Urban yellow fever: Large epidemics occur when infected people introduce the virus into heavily populated areas with high density of Aedes aegypti mosquitoes and where most people have little or no immunity, due to lack of vaccination or prior exposure to yellow fever.
  • In these conditions, infected mosquitoes transmit the virus from person to person.


  • Zika virus disease is caused by a virus transmitted primarily by Aedes
  • People with Zika virus disease can have symptoms including mild fever, skin rash, conjunctivitis, muscle and joint pain, malaise or headache. These symptoms normally last for 2-7
  • There is scientific consensus that Zika virus is a cause of microcephaly and Guillain-Barré syndrome. Links to other neurological complications are also being
  • Zika virus is primarily transmitted to people through the bite of an infected mosquito from the Aedes genus, mainly Aedes aegypti in tropical
  • Aedes mosquitoes usually bite during the day, peaking during early morning and late afternoon/evening. This is the same mosquito that transmits dengue, chikungunya and yellow
  • Sexual transmission of Zika virus is also possible. Other modes of transmission such as blood transfusion are being investigated.


  • A zoonosis is any disease or infection that is naturally transmissible from vertebrate animals to humans
  • Zoonoses comprise a large percentage of new and existing diseases in humans
  • Some zoonoses, such as rabies, are 100% preventable through vaccination and other methods
  • A zoonosis is an infectious disease that has jumped from a non-human animal to humans.
  • Zoonotic pathogens may be bacterial, viral or parasitic, or may involve unconventional agents and can spread to humans through direct contact or through food, water or the environment.
  • They represent a major public health problem around the world due to our close relationship with animals in agriculture, as companions and in the natural environment.
  • Zoonoses can also cause disruptions in the production and trade of animal products for food and other uses.
  • Zoonotic pathogens can spread to humans through any contact point with domestic, agricultural or wild animals.
  • As part of the One Health approach, the World Health Organization collaborates with the Food and Agriculture Organization of the United Nations (FAO) and the World Organisation for Animal Health (OIE) on the Global Early Warning System for Major Animal Diseases (GLEWS).
  • Prevention methods for zoonotic diseases differ for each pathogen; however, several practices are recognized as effective in reducing risk at the community and personal levels.
  • Antimicrobial resistance is a complicating factor in the control and prevention of zoonoses.


  • Any disease that is required by law to be reported to government authorities.
  • The collation of information allows the authorities to monitor the disease, and provides early warning of possible outbreaks.
  • The WHO’s International Health Regulations, 1969 require disease reporting to the WHO in order to help with its global surveillance and advisory role.
  • Registered medical practitioners need to notify such diseases in a proper form within three days, or notify verbally via phone within 24 hours depending on the urgency of the situation.
  • Every government hospital, private hospital, laboratories, and clinics will have to report cases of the disease to the government.
  • The Centre has notified several diseases such as cholera, diphtheria, encephalitis, leprosy, meningitis, pertussis (whooping cough), plague, tuberculosis, AIDS, hepatitis, measles, yellow fever, malaria dengue, Covid-19, Black Fungus etc.
  • Any failure to report a notifiable disease is a criminal offence and the state government can take necessary actions against defaulters.


  • A contagious disease in goats and sheep, characterised by exudative inflammation followed by necrosis of the epidermal tissues, causing separation of the hoof from the underlying soft tissue.
  • The affected animals exhibit lameness, loss of body condition due to a fall in diet, causing reduced wool and meat production, apart from decreased fertility.
  • The disease is not just painful for the animals but also a nightmare for the cattle rearers, as it results in huge fall in returns on their investment.
  • The disease caused by ‘ Dichelobacter nodosus ’ bacteria. The bacteria generally infests in muddy soil and spreads to the flock during the rainy season
  • In India, the disease is predominantly reported from Tamil Nadu, Karnataka and Andhra Pradesh, though its first confirmed outbreak was found in the Jammu & Kashmir.


  • A serious viral disease affecting many marine, brackishwater and freshwater fishes resulting in 100% mortality in larval and early juvenile stages.
  • Red-spotted grouper nervous necrosis virus (RGNNV) is the only genotype prevalent in India and most other tropical countries. Infected adults remain as carriers and transmit the virus to offspring through eggs.
  • The disease is caused by nervous necrosis virus (NNV).
  • The practical way to control the disease and prevent vertical transmission is to vaccinate fingerlings and adult fish.
  • The new vaccine, Nodavac-R, developed by Central Institute of Brackishwater Aquaculture (CIBA) can be injected to fingerlings. It was the first vaccine to be released for aquaculture in India.


  • A disease affecting cattle, caused by a ‘capripox virus’.
  • Causes fever, depression, skin nodules and oedema, enlarged lymph nodes, milk drop, swelling in the legs and lameness.
  • There is no treatment for LSD.
  • It is not fully understood how lumpy skin disease virus is transmitted between animals.
  • It is believed that LSD virus is mainly transmitted by blood-sucking insect vectors like mosquitoes, flies and ticks or by contaminated needles.
  • Can be found in the blood for up to 21 days post-infection but shedding in semen may continue for at least 42 days post-infection.
  • The LSD has remained confined to Africa, where it was first discovered in 1929, after that it has seen in many countries of Asia and Europe.


  • It is a disease which infects animals that come in contact with contaminated water or soil by a contagious bacterium (Pasteurella multocida).
  • In this disease the respiratory tract and lungs of the animals are affected, leading to severe pneumonia.
  • It mainly affects water buffalo, cattle and bison with a high mortality rate in infected animals.
  • Generally, spreads in the period right before and after the monsoons.


  • A fungal disease caused by Rhizoctonia solani. Infected leaves senesce or dry out and die more rapidly, young tillers can also be destroyed.
  • Sheath blight occurs in areas with high temperature (28−32°C), high levels of nitrogen fertilizer, and relative humidity of crop canopy from 85−100%.
  • Plants are more vulnerable to sheath blight during the rainy season.
  • Sheath blight is predominantly controlled by spraying of fungicides and we end up spending profusely on fungicides, which add to the cost of rice production. Also, the residual level of fungicides adds negative trade value, as beyond certain permissible level, the rice is considered not suitable for international trade.
  • Moreover, beside rice, the pathogen is known to cause disease on a wide range of agriculturally important crops, including tomato.


  • Neglected tropical diseases (NTDs) are a diverse group of tropical infections which are common in low-income populations in developing regions of Africa, Asia, and the Americas. Neglected Tropical Diseases: Progress and Challenges for the Post-2015 Development Era - Science in the News
  • They are caused by a variety of pathogens such as viruses, bacteria, protozoa and parasitic worms (helminths).
  • These diseases are contrasted with the big three infectious diseases (HIV/AIDS, tuberculosis, and malaria), which generally receive greater treatment and research funding.
  • These diseases generally receive less funding for research and treatment than malaises like tuberculosis, HIV-AIDS and malaria. Some examples of NTDs include snakebite envenomation, scabies, yaws, trachoma, Leishmaniasis and Chagas disease.


  • Referred to as ‘banana cancer’.
  • Fungal disease called Fusarium oxysporum f. Sp cubense.
  • Afflicts banana plants
  • affects the Cavendish variety or the G9 Banana cultivar
  • Its strains is called ‘Tropical Race 4’ or ‘TR4’
  • For the first time, Indian scientists have brought out a biopesticide that can control the disease.
  • In India, more than 60 per cent of bananas are of the G9 variety.
  • They go by names like ‘Grand Naine’, ‘Robusta’, ‘Bhusaval’, ‘Basrai’ and ‘Shrimanth’.


  • The current outbreak of African Swine Fever (ASF) in India (in Assam and in Arunachal Pradesh) is the first time that the disease has been reported in the country.
  • African Swine Fever (ASF) does not affect humans but can be catastrophic for pigs.
  • ASF is a severe viral disease that affects wild and domestic pigs typically resulting in an acute haemorrhagic fever. The disease has a case fatality rate (CFR) of almost 100 per cent.
  • It is less infectious than other animal diseases such as foot-and-mouth disease.
  • There is no approved vaccine
  • it is differentiated from Classical Swine Fever (CSF), whose signs may be similar to ASF, but is caused by a different virus for which a vaccine exists.
  • Its routes of transmission include direct contact with an infected or wild pig (alive or dead), indirect contact through ingestion of contaminated material such as food waste, feed or garbage, or through biological vectors such as ticks.


  • It affects children.  a syndrome of unknown cause that results in a fever and mainly affects children under 5 years of age.
  • Its symptoms include red eyes, rashes, and a swollen tongue with reddened lips — often termed strawberry tongue — and an inflamed blood vessel system all over the body.
  • There is constant high fever for at least five days.
  • The disease also affects coronary functions in the heart.
  • The disease derives its name from a Japanese paediatrician, Tomisaku Kawasaki, who reported the first case in 1961 — a four-year-old boy — and later found similar cases in other children.


  • Canine distemper is a contagious viral disease that attacks the respiratory, gastrointestinal and nervous systems of a wide variety of animal species, including dogs, coyotes, foxes, pandas and wolves.
  • It is also known as hardpad disease.
  • It is caused by a single-stranded RNA virus of the family Paramyxoviridae (the same family of the viruses that causes measles, mumps, and bronchiolitis in humans).
  • This virus is similar to the measles virus in humans and the rinderpest virus which affects cattle.
  • The disease is highly contagious via inhalation. The virus can also be transmitted by shared food and water bowls and equipment.
  • There is no cure for canine distemper infection. Treatment typically consists of supportive care and efforts to prevent infections.


  • It is well known that while people of all age groups are susceptible to the disease, those above 60 years of age and with co-morbidities are especially vulnerable to it.
  • Even so, there have been reports of some young people, including teenagers, also succumbing to the disease.
  • Earlier in April, research suggested that the disease might induce what is known as a “cytokine storm” in some patients.
  • Such a storm is characterised by the overproduction of immune cells and cytokines themselves, which can be harmful since an excess of immune cells can damage the healthy tissue.
  • Ideally, once the immune system is triggered after the body is infected by a pathogen, the immune cells will reach the site of infection or injury and start the repair.
  • But in case of a CSS, the excess of immune cells start to damage the healthy tissue as well.
  • CSS is seen as a likely major cause of mortality in both the 1918-20 Spanish Flu, which killed more than 50 million people worldwide, and the H1N1 (swine flu) and H5N1 (bird flu) outbreaks in recent years. If the clinical features of CSS are not identified on time, the syndrome can lead to multiple organ failure, sepsis and even death.


  • Holoendemic Diseases:
    • This kind of endemic disease affects mostly children. This infection is highly prevalent in the early years of life. The adult population do not show traces of diseases as much as children do. Malaria is a type of holoendemic disease.
  • Hyperendemic Diseases:
    • These types of endemic diseases are constantly present at a high rate and are found among all age groups equally. E.g. African Sleeping Sickness and Chicken Pox.


  • It is a progressive genetic disorder which affects the brain.
  • It causes uncontrolled movements, impaired coordination of balance and movement, a decline in cognitive abilities, difficulty in concentrating and memory lapses, mood swings and personality changes.
  • The HTT genes are involved in the production of a protein called huntingtin.
  • They provide the instruction for making the protein.
  • Mutated genes provide faulty instructions leading to production of abnormal huntingtin proteins and formation of clumps.
  • These clumps disrupt the normal functioning of the brain cells, which eventually leads to death of neurons in the brain, resulting in Huntington disease.
  • No cure exists, but drugs, physiotherapy and talk therapy can help manage some symptoms.


  • It is a respiratory disease of pigs, which is caused by type A influenza virus that regularly causes outbreaks of influenza in pig populations.
  • According to the US Centers for Disease Control and Prevention (CDC), while the swine flu causing virus leads to a high number of infections in pig herds, the disease is not as fatal and causes few deaths.
  • Specific swine influenza vaccines are available for pigs.
  • The swine flu viruses are spread among pigs through close contact and through contaminated objects moving between infected and uninfected pigs.
  • Symptoms include fever, depression, coughing, discharge from the nose and eyes, eye redness or inflammation.


  • It is a rare illness that causes inflammation of the blood vessels leading to low blood pressure. It affects the entire body as it causes a build-up of fluid in the lungs and other organs.
  • Patients suffering from it require intensive care to support the lungs, heart and other organs.
  • Symptoms:
    • Abdominal and gastrointestinal symptoms.
    • Cardiac inflammation.
    • Overlapping symptoms of Toxic Shock Syndrome (TSS) and Kawasaki disease as well.


  • Detected in the wheat crop which drop in the crop’s yield.
  • Yellow rust or stripe rust is a fungal disease which attacks the leaves, affects their photosynthes.
  • It is a disease of cool weather in North India.
  • The recent rains, increase in the temperature and humid conditions are favourable for yellow rust.


  • Merriam-Webster says yada yada is “boring or empty talk”, a way to recount words that are “too dull or predictable to be worth repeating”. The Cambridge dictionary says yada yada is only “blah blah blah”.
  • Yada Yada is an alphavirus, a group of viruses that the researchers described as “small, single-stranded positive-sense RNA viruses (that) include species important to human and animal health, such as Chikungunya virus and Eastern equine encephalitis virus… (and which) are transmitted primarily by mosquitoes and (are) pathogenic in their vertebrate hosts”.
  • Unlike some other alphaviruses, Yada Yada does not pose a threat to human beings.
  • The virus was detected in mosquitoes trapped as part of the Victorian Arbovirus Disease Control Programme in Encephalitis Virus Surveillance traps set up overnight in three locations in Victoria, Australia, for seven weeks in late 2016, the researchers reported.


  • Broadly, a ‘rare disease’ is defined as a health condition of low prevalence that affects a small number of people when compared with other prevalent diseases in the general population.
  • While there is no universally accepted definition of rare diseases, countries typically arrive at their own descriptions, taking into consideration disease prevalence, its severity and the existence of alternative therapeutic options.
  • India does not have a definition of rare diseases because there is a lack of epidemiological data on their incidence and prevalence.
  • According to the policy, rare diseases include genetic diseases, rare cancers, infectious tropical diseases, and degenerative diseases.
  • As per the policy, out of all rare diseases in the world, less than five per cent have therapies available to treat them.
  • In India, roughly 450 rare diseases have been recorded from tertiary hospitals, of which the most common are Haemophilia, Thalassemia, Sickle-cell anemia, auto-immune diseases, Gaucher’s disease, and cystic fibrosis.


  • It is a rare disease that occurs in 1 out of 700-1,000 individuals.
  • Globally, there are over 12.5 million such cases, but only a fourth of them are believed to be aware of their condition.
  • Even so, as inherited kidney disorders go, ADPKD is among the most common.
  • It is also one of the most common causes of end-stage kidney disease (when kidneys can no longer function properly).
  • Numerous cysts grow in the kidneys, and the most common symptoms include pain in the back and between the ribs and hips, headaches, blood in the urine, high blood pressure, and kidney insufficiency.
  • Though a kidney disease, ADPKD can affect other organ systems leading to a multisystem disorder.
  • Organs that can be affected include the liver, pancreas, prostrate and glands of the male reproductive tract.


  • It is a progressive brain disorder that typically affects people older than 65. When it affects younger individuals, it is considered early onset.
  • The disease destroys brain cells and nerves, and disrupts the message-carrying neurotransmitters.
  • Eventually, a person with Alzheimer’s loses the ability to perform day-to-day activities.
  • There is no cure for Alzheimer’s, because its exact causes are not known. Most drugs being developed try to slow down or stop the progression of the disease.
  • China recently announced that a new drug, meant to potentially treat Alzheimer’s disease, will be available to Chinese patients by the end of this year.
  • Called GV-971 or “Oligomannate”, it is a seaweed-based drug, administered orally.


  • An insect-transmitted viral disease of domestic and wild ruminants that includes the camelid species.
  • The disease is widespread among the sheep, goats, cattle, buffaloes and camels in the country.
  • With the help of the Kit “Bluetongue: Sandwich ELISA for detection of Antigen”, the Bluetongue Virus can be controlled with the vaccination of susceptible animals, vector control and quarantine of infected animals with the good management practices.
  • Apart from the vaccination, the early diagnosis and isolation of the infected animals are one of the commonly suggested preventive methods for controlling the spreading of the disease.


  • Elephant Endotheliotropic Herpesvirus (EEHV) is a rare disease that has killed five elephants in Odisha.
  • EEHV is as a type of herpes virus that can cause a highly fatal hemorrhagic disease in young Asian elephants between the ages of 1 and 12.
  • If a young elephant dies before reproducing, it affects the population of the species as a whole in the concerned geography.
  • When EEHV is triggered, the elephant dies of massive internal bleeding and symptoms which are hardly visible, like reduced appetite, nasal discharge, and swollen glands.
  • The disease is usually fatal, with a short course of 28-35 hours.
  • There is no cure for herpes viruses in animals or in humans


  • ‘Human Papilloma Virus (HPV)’ causes penile cancer in men and cervical, vaginal, anal & vulvar cancer in women.
  • It can also cause throat or rectum cancer in both men and women.
  • The virus is transmitted through intimate contact like – sexual intercourse, oral or anal sex.
  • It poses a higher risk for HIV-infected persons, smokers, and people dependent on hormonal contraceptives.
  • The Vaccine – In India, two vaccines namely “Gardasil” & “Cervarix” are available.



  • The virus can be transmitted to humans from animals (such as bats or pigs). The disease spreads through fruit bats or ‘flying foxes,’ of the genus Pteropus, who are natural reservoir hosts of the Nipah and Hendra viruses.
  • Nipah virus infection is an emerging zoonotic disease of public health importance in the WHO South East Asia region with a high case fatality rate estimated to range between 40 and 75 per cent.
  • It was first recognised in 1998-99 during an outbreak among pig farmers in Malaysia and Singapore.
  • Human-to-human transmission of this virus has also been reported among family and care givers of infected patients.
  • The virus is present in bat urine and potentially, bat faeces, saliva and birthing fluids.
  • Furthermore, transmission between farms may be due to fomites – or carrying the virus on clothing, equipment, boots, and vehicles.


  • Also known as Asperger’s, is a neurodevelopmental disorder characterized by significant difficulties in social interaction and nonverbal communication, along with restricted and repetitive patterns of behavior and interests.
  • It is an autism spectrum disorder (ASD), but differs from other ASDs by relatively unimpaired language and intelligence.


  • Rotavirus is a leading cause of severe diarrhoea and death among children less than five years of age.
  • It is responsible for around 10% of total child mortality every year.
  • Rotavirus-Signs and Symptoms:
  1. Kids with a rotavirus infection have fever, nausea, and vomiting, often followed by abdominal cramps and frequent, watery diarrhea.
  2. Kids may also have a cough and runny nose.
  3. Sometimes the diarrhea that accompanies a rotavirus infection is so severe that it can quickly lead to dehydration.
  4. As with all viruses, though, some rotavirus infections cause few or no symptoms, especially in adults.
  5. Rotavirus is transmitted by the faecal-oral route, via contact with contaminated hands, surfaces and objects, and possibly by the respiratory route. Viral diarrhea is highly contagious.
  6. Currently, two vaccines are available against rotavirus:
    1. Rotarix (GlaxoSmithKline): is a monovalent vaccine recommended to be orally administered in two doses at 6-12 weeks.
    2. Rota Teq (Merck) is a pentavalent vaccine recommended to be orally administered in three doses starting at 6-12 weeks of age.


  • It is caused by Kyasanur Forest disease Virus (KFDV), a member of the virus family Flaviviridae.
  • It was first identified in 1957 in a sick monkey from the Kyasanur Forest in Karnataka. Since then, between 400-500 humans’ cases per year have been reported.
  • KFD is endemic to the Indian state of Karnataka.
  • Rodents, shrews, and monkeys are common hosts for KFDV after being bitten by infected Hard ticks (Haemaphysalis Spinigera). KFDV can cause epizootics (outbreak of disease in animals) with high fatality in primates.
  • Transmission: To humans, it may occur after a tick bite or contact with an infected animal (a sick or recently dead monkey).
  • Signs and Symptoms: After an incubation period of 3-8 days, the symptoms like chills, fever, headache, severe muscle pain, vomiting, gastrointestinal symptoms and bleeding may occur. Patients may experience abnormally low blood pressure, and low platelet, red blood cell, and white blood cell counts.
  • Diagnosis: It can be diagnosed in the early stage of illness by molecular detection by Polymerase Chain Reaction (PCR) or virus isolation from blood. Later, serologic testing using enzyme-linked immunosorbent serologic assay (ELISA) can be performed.
  • Treatment and Prevention: There is no specific treatment for KFD although a vaccine is available.


  • A lesser-known disease that mainly affects children and is more common in East Asia, particularly Japan.
  • It is a rare cause of stroke among children.
  • Moyamoya disease is a rare blood vessel (vascular) disorder in which the carotid artery in the skull becomes blocked or narrowed, reducing blood flow to the brain. Tiny blood vessels then develop at the base of the brain in an attempt to supply it with blood.
  • This may cause a ministroke or a transient ischemic attack, stroke, or bleeding in the brain.
  • It can also affect how your brain functions and cause cognitive and developmental delays or disabilities.
  • While it may occur at any age, most symptoms commonly occur between 5 and 10 years of age in children and between 30 and 50 years of age in adults.
  • However, it causes different symptoms in adults and children. In children, the first symptom is usually a stroke or recurrent transient ischemic attack, while adults may experience bleeding in the brain (hemorrhagic stroke) from abnormal brain vessels, along with stroke.
  • Spotting symptoms early is very important to prevent serious complications such as a stroke.
  • Moyamoya syndrome is also associated with certain conditions, such as Down syndrome, sickle cell anemia, neurofibromatosis type 1 and hyperthyroidism.
  • Since it has genetic factors involved it is not possible to completely prevent this disease, however when symptoms develop in children they should be investigated and treatment should be started early to prevent complications. Surgical treatment can be done to bypass blood to the area of the brain where narrowed or blocked blood vessels are not able to supply blood.
  • Countries like Korea, Japan and China are most affected due to “certain genetic factors in those populations.


  • It is a rare but serious fungal infection.
  • Also known as mucormycosis.
  • The disease often manifests in the skin and also affects the lungs and the brain.
  • Caused by a group of moulds known as mucormycetes present naturally in the environment.
  • It mainly affects people who are on medication for health problems that reduces their ability to fight environmental pathogens.
  • It enters through the nose and then spreads to the eyes, paralyses the muscles around the pupils which might lead to blindness.
  • It may also cause meningitis if it spreads to the brain.
  • Mucormycosis is of several types, of which the commonest is rhino-orbital-cerebral mucormycosis.
  • Other forms of mucormycosis include the pulmonary form in which the lungs are mainly involved and less common cutaneous mucormycosis or disseminated mucormycosis, where it spreads throughout the body. The last two are also associated with very poor prognosis.
  • Symptoms: Sinuses or lungs of such individuals get affected after they inhale fungal spores from the air. Warning signs include pain and redness around the eyes or nose, with fever, headache, coughing, shortness of breath, bloody vomits, and altered mental status.


  • A rare, inherited disorder where fatty cells build up in areas including the liver, spleen and bone tissue and marrow.
  • The organs enlarge—sometimes as much as 50 times its normal size for the spleen—and bones are affected, which increases the risk of fracture and severe bone pain (called a “bone crisis”) that requires joint replacement.
  • The disease is caused by the body not having enough of an important enzyme (glucocerebrosidase), which breaks down a fatty chemical (glucocerebroside).
  • Gaucher disease is divided into three main categories:
  • Type 1 is the most common form of the disorder in Western countries, constituting approximately 95 percent of patients.
  • Type 2 is rare and is associated with severe neurological abnormalities and is usually fatal within the first two years of onset.
  • Type 3 is rare in the United States and Europe, but it is the most common form of the disease around the world. It has the same symptoms as type 1, plus some neurological damage.
  • Symptoms of Gaucher disease type 1 can differ vastly and can range from severe to none at all. Some signs include:
  • Swollen belly (from spleen and liver enlargement)
  • Bone pain and easily fractured bones
  • Anemia (low red blood cell counts) and fatigue
  • Bleeding (frequent nosebleeds, gum bleeding) and bruising problems (caused by decrease in blood platelets)
  • To have Gaucher disease, you must have two mutations of a gene called GBA: one from your mother and one from your father. But you can be a carrier and have just one mutation related to the disorder and not have Gaucher disease.
  • If both parents are carriers, each pregnancy has a 1 in 4 chance that the baby will have the disease. Today, prenatal testing can be done early in the pregnancy, which people with a family history of the disease may want to consider.
  • Type 1 Gaucher disease, as well as the non-neurological symptoms of type 3, are treatable. Available therapies include:
    • Enzyme replacement therapy (ERT): This balances the low levels of glucocerebrosidase, which is the underlying cause of Gaucher disease. Patients receive intravenous infusions of the enzyme every two weeks.
    • Substrate reduction therapy (SRT): This is an oral medication that decreases the rate of formation of glucocerebroside in the body so that excess buildup is reduced.


  • Wilson disease is a rare inherited disorder in which the body is unable to rid itself of extra copper.
  • Copper is found in many foods, including meat (liver), seafood (shellfish), nuts, seeds, grain, and cocoa products.
  • Typically, the body stores some copper in the liver, but under normal circumstances, excess copper is excreted into the gut through bile formed by the liver.
  • But if you have Wilson disease, the copper accumulates in your liver and then is released directly into your bloodstream—thereby damaging your liver, brain, and other organs. 
  • Wilson disease is an inherited disease and is present at birth.
  • Symptoms typically arise in childhood or adolescence though sometimes may not even be noticeable until well into adulthood. Some of the oldest patients to be diagnosed were in their 80s, but most patients present by age 45. 
  • The disease first attacks the liver and then the central nervous system—but both may be affected simultaneously, causing liver, neurological, and psychiatric problems.
  • A rusty brown halo around the eye’s cornea known as a Kayser Fleischer ring is a common sign of the disease but may not be present early on.
  • Treatment is geared around removing the extra copper from your body and preventing it from accumulating again. The first step is to take chelating agents, which are medications that force your organs to release copper into the bloodstream.


  • In a patient with Parkinson’s, specific groups of brain cells are affected: the dopamine-producing cells. Dopamine is a chemical that is essential for motor control, balance, and muscle movement.
  • While the exact cause of this cell type depletion is unknown, age is the greatest risk factor. The typical age range for onset is between 55 and 65.
  • Parkinson’s diseaseis one of the most common neurological disorders which prevails most in the elderly age group.
  • It is a condition in which a patient holds limited or no control over his movements and body balance.
  • It occurs and progresses with ageing, but in rare cases, it is also witnessed among children and teenagers as well. Also, men are more prone to Parkinson’s disease than women.
  • Parkinson’s is a progressive disease though the rate of deterioration may vary in different individuals.
  • The two main types of Parkinson’s include the following:
  • Akineticrigid: In this type of the disease, a patient will move slowly and experience muscle stiffness throughout their body. 
  • Tremor-dominant: Patients with this subtype experience shaking or tremors, and milder muscle stiffness. 
  • Parkinson’s disease is a progressive disease, and patients are sometimes not treated with medication initially.


  • Caused by the gradual buildup of cholesterol or plaque, which makes the arteries stiffen and narrow. The result is reduced blood flow to the heart.
  • Multiple causes of coronary artery disease include:
  • Genetics: Having a family history of heart disease
  • Lifestyle: Eating unhealthy, high-fat foods and being sedentary
  • Medical conditions: Including diabetes, high cholesterol and high blood pressure
  • Many people with heart disease have more than one of those risk factors.
  • People with coronary artery disease are at higher risk for a heart attack and other heart conditions that can be debilitating or even fatal. This leads to symptoms such as cardiac angina, the clinical term for shortness of breath and chest pain.
  • A sudden heart attack may be caused by a blood clot that forms on the surface of the plaque.


  • Lyme disease, a common vector-borne condition in the United States, is transmitted through infected deer ticks.
  • Also known as Lyme borreliosis, it is a bacterial disease caused by the borrelia bacterium which is spread by the black-legged, Ixodes ticks which are usually of the Ixodes scapularis type.
  • Lyme disease is rare in India, although some cases have been reported in the past.
  • How do people contract the disease?
    • The small ticks feed on blood of birds and mice, and then bite humans, contaminating their blood.
    • After the tick injects the bacteria into the blood, the bacteria grows locally which is called Early-localised disease. When it spreads into the blood it is called disseminated disease, which causes damage to various organs.
    • Later, it causes various complication of the lymes disease.
    • These ticks are found in shrubs, bushes and on wooded areas, and may get attached to the human host when they come in contact during outdoor activities.
    • All ticks do not carry the organism, but when they do, they need to be attached to the host for a period of at least 36 to 48 hours, in order to transmit the bacterium.
    • Causes
      • The cause is only one – a bite from deer tick.
      • There is no other cause.
    • Who does it affect?
      • From a child to an adult and an elderly, lyme disease can affect anyone. Anyone who gets bitten by a tick carrying the virus can be infected.
      • Symptoms:
        • Early manifestations are flu-like, including fever, fatigue, myalgia, viral fever, body pain, headache, joint pains and swollen lymph nodes. The most specific symptom is a rash that is called erythema migrans.
      • Precautions
        • Prevention is the best way to avoid lyme disease. It is wise to shower after coming indoors.
        • Watch out for ticks on the body (which are the size of poppy seeds) and put clothes in a hot dryer to get rid of ticks.
        • Antibiotics, oral and injections, both are available. The treatment takes about three to four weeks. This condition is completely treatable.
        • There is no vaccine to prevent lyme disease
        • One can also apply insect repellents containing DEET or diethyltoluamide.


  • Recently, Odisha reported its first-ever case of a baby born with Harlequin Ichthyosis, a rare genetic skin condition.
  • India’s first recorded case of a baby born with harlequin ichthyosis was in 2016, at a private hospital in Nagpur, Maharashtra.
  • Harlequin Ichthyosis is a rare genetic skin disorder to a newborn infant.
  • It’s a type of ichthyosis, which refers to a group of disorders that cause persistently dry, scaly skin all over the body.
  • It is inherited in an autosomal recessive pattern.
  • It can be caused by changes (mutations) in the ABCA12 gene.
  • ABCA12 Gene gives instructions for making a protein that is necessary for skin cells to develop normally.
  • It plays a key role in the transport of fats (lipids) to the most superficial layer of the skin (epidermis), creating an effective skin barrier.
  • When this gene is mutated, the skin barrier is disrupted.
  • Newborn infants are covered with plates of thick skin that crack and split apart and can restrict breathing and eating.
  • Premature birth is typical, leaving the infants at risk for complications from early delivery.


  • There are several different types of vaccines. Each type is designed to teach your immune system how to fight off certain kinds of germs—and the serious diseases they cause.
  • When scientists create vaccines, they consider:
    • How your immune system responds to the germ
    • Who needs to be vaccinated against the germ
    • The best technology or approach to create the vaccine
  • Based on a number of these factors, scientists decide which type of vaccine they will make. There are several types of vaccines, including:
    • Inactivated vaccines
    • Live-attenuated vaccines
    • Messenger RNA (mRNA) vaccines
    • Subunit, recombinant, polysaccharide, and conjugate vaccines
    • Toxoid vaccines
    • Viral vector vaccines

Inactivated vaccines

  • Inactivated vaccines use the killed version of the germ that causes a disease.
  • Inactivated vaccines usually don’t provide immunity (protection) that’s as strong as live vaccines. So you may need several doses over time (booster shots) in order to get ongoing immunity against diseases.
  • Inactivated vaccines are used to protect against:
    • Hepatitis A
    • Flu (shot only)
    • Polio (shot only)
    • Rabies

Live-attenuated vaccines

  • Live vaccines use a weakened (or attenuated) form of the germ that causes a disease.
  • Because these vaccines are so similar to the natural infection that they help prevent, they create a strong and long-lasting immune response. Just 1 or 2 doses of most live vaccines can give you a lifetime of protection against a germ and the disease it causes.
  • But live vaccines also have some limitations. For example:
    • Because they contain a small amount of the weakened live virus, some people should talk to their health care provider before receiving them, such as people with weakened immune systems, long-term health problems, or people who’ve had an organ transplant.
    • They need to be kept cool, so they don’t travel well. That means they can’t be used in countries with limited access to refrigerators.
    • Live vaccines are used to protect against:
      • Measles, mumps, rubella (MMR combined vaccine)
      • Rotavirus
      • Smallpox
      • Chickenpox
      • Yellow fever

Messenger RNA vaccines—also called mRNA vaccines

  • Researchers have been studying and working with mRNA vaccines for decades and this technology was used to make some of the COVID-19 vaccines. mRNA vaccines make proteins in order to trigger an immune response. mRNA vaccines have several benefits compared to other types of vaccines, including shorter manufacturing times and, because they do not contain a live virus, no risk of causing disease in the person getting vaccinated.
  • mRNA vaccines are used to protect against COVID-19

Subunit, recombinant, polysaccharide, and conjugate vaccines

  • Subunit, recombinant, polysaccharide, and conjugate vaccines use specific pieces of the germ—like its protein, sugar, or capsid (a casing around the germ).
  • Because these vaccines use only specific pieces of the germ, they give a very strong immune response that’s targeted to key parts of the germ. They can also be used on almost everyone who needs them, including people with weakened immune systems and long-term health problems.
  • One limitation of these vaccines is that you may need booster shots to get ongoing protection against diseases.
  • These vaccines are used to protect against:
    • Hib (Haemophilus influenzae type b) disease
    • Hepatitis B
    • HPV (Human papillomavirus)
    • Whooping cough (part of the DTaP combined vaccine)
    • Pneumococcal disease
    • Meningococcal disease
    • Shingles

Toxoid vaccines

  • Toxoid vaccines use a toxin (harmful product) made by the germ that causes a disease. They create immunity to the parts of the germ that cause a disease instead of the germ itself. That means the immune response is targeted to the toxin instead of the whole germ.
  • Like some other types of vaccines, you may need booster shots to get ongoing protection against diseases.
  • Toxoid vaccines are used to protect against:
    • Diphtheria
    • Tetanus

Viral vector vaccines

  • For decades, scientists studied viral vector vaccines. Some vaccines recently used for Ebola outbreaks have used viral vector technology, and a number of studies have focused on viral vector vaccines against other infectious diseases such as Zika, flu, and HIV. Scientists used this technology to make COVID-19 vaccines as well.
  • Viral vector vaccines use a modified version of a different virus as a vector to deliver protection. Several different viruses have been used as vectors, including influenza, vesicular stomatitis virus (VSV), measles virus, and adenovirus, which causes the common cold.
  • Adenovirus is one of the viral vectors used in some COVID-19 vaccines being studied in clinical trials. Viral vector vaccines are used to protect against: COVID-19


  • This disease usually affects animals and can spread to human beings if they are travelling through waterlogged areas.
  • “Bacteria called leptospira which present in the excreta and urine of animals can infect human beings if they are exposed to it – they can be exposed if they are wading through contaminated water, if there is a cut in the skin which has been exposed to the bacteria.”
  • The common symptoms of leptospirosis include fever, rash, body ache, and vomiting. This can be treated with antibiotics.
  • However, if leptospirosis is left untreated, it can cause kidney damage and even prove to be fatal.
  • To prevent contracting this disease, here are some precautions the doctor recommends:
    • Avoid walking through stagnant water
    • Wear closed footwear
    • Dress all your wounds and cuts
    • If you have walked through stagnant water, wash your arms and legs with soap and water.


  • A rare (estimated at 1 in every 40,000 births), inherited and often fatal disorder that disables the heart and skeletal muscles.
  • It is caused by mutations in a gene that makes an enzyme called acid alpha-glucosidase (GAA).
  • Pompe disease is a genetic disorder in which complex sugar called glycogen builds up in the body’s cells.
  • Since this is a genetic condition, the people who get this disease inherit it from a parent.
  • Enzyme replacement therapy (ERT) is an approved treatment for all Pompe patients.


  • Also known as the winter vomiting bug
  • A group of highly contagious viruses that cause vomiting and diarrhoea.
  • Transmitted through contaminated food, water or surface.
  • A direct contact with an infected person will also result in the transmission.
  • No specific medicines to treat the infection, experts are recommending the intake of large amounts of fluid to relieve symptoms and prevent dehydration.
  • Also causes stomach pain and nausea.
  • No vaccines are available for the disease.
  • It is the most common pathogen implicated in outbreaks of gastrointestinal disease.


  • A highly contagious viral disease that can also be life-threatening in puppies and dogs
  • Affects the intestinal tract of canines with puppies being more susceptible
  • Virus has reported a 90 per cent mortality rate
  • Spreads through direct contact with an infected dog or by indirect contact
  • Indirect transmission occurs when a person who has recently been exposed to an infected dog touches the puppy
  • Parvovirus has no cure and inoculating a puppy or a dog gives them a fighting chance against the infection.


  • Trachoma caused by bacteria, damages the eyelids, causes the eyelashes to turn inwards
  • If not corrected with surgery, it can lead to irreversible vision loss and blindness.
  • One of Neglected tropical diseases (NTDs).
  • In News: Gambia becomes 2nd African State to Eliminate Trachoma after Ghana did in 2018.


  • Highly virulent disease that causes hemorrhagic fever and is in the same family of viruses that cause Ebola
  • Carried by bats and has a fatality rate of up to 88 per cent.
  • Usually associated with exposure to caves or mines housing colonies of Rousettus bats
  • Can spread through human-to-human transmission
  • Symptoms: High fever, severe headache and severe malaise accompanied by Muscle aches and pains
  • Treatment
    • no proven treatment or vaccine available
    • difficult to clinically distinguish Marburg virus disease from other infectious diseases
    • diagnostic of the virus can be done using antigen detection tests, serum neutralization tests, virus isolation by cell culture or through RT-PCR.
    • rehydration with oral or intravenous fluids can be analysed to delay the outcomes.


  • Broadly defined as diseases that infrequently occur in a population, and three markers are used:
    • the total number of people with the disease,
    • its prevalence, and
    • the availability/non-availability of treatment options.
  • WHO defines rare disease as having a frequency of less than 6.5-10 per 10,000 people.
  • As per an estimate, there are 7,000 known rare diseases with an estimated 300 million patients in the world; 70 million are in India.
  • According to the Organization for Rare Diseases India, these include inherited cancers, autoimmune disorders, congenital malformations, Hirschsprung’s disease, Gaucher disease, cystic fibrosis, muscular dystrophies and Lysosomal Storage Disorders (LSDs).


  • An alphaherpesvirus enzootic in macaques of the genus Macaca.
  • B virus is the only identified old-world-monkey herpes virus that displays severe pathogenicity in humans.
  • Infection can be transmitted via direct contact and exchange of bodily secretions of monkeys
  • B virus can survive for hours on surfaces, particularly when moist.
  • Humans can get infected if they are bitten or scratched by an infected monkey.
  • Symptoms: Flu-like fever and chills, muscle ache, fatigue and headache, causes inflammation (swelling) of the brain and spinal cord, leading to neurologic and inflammatory symptoms
  • There are no vaccines.


  • With the threat of Yellow Leaf Disease spreading to vast
    tracts of arecanut plantations looming large, farmers in the State’s coastal belt have now begun commercial cultivation of bamboo in a small way.
  • Abnormal yellowing of leaf tissue is called chlorosis.
  • Leaves lack the essential green pigment chlorophyll.
  • Possible causes include poor drainage, damaged roots,
    compacted roots, high soil pH, and nutrient deficiencies in the plant.


  • A regular, affordable penicillin treatment can prevent the
    risk of underlying rheumatic heart disease (RHD) progression in children and adolescents, according to a new study.
  • RHD is serious heart damage caused by rheumatic fever a condition arising from poorly treated, repeat infections of streptococcus bacteria.
  • RHD remains a public health concern in low-resource countries like Uganda, where it is the most common cause of heart disease in young adults.


  • The World Health Organization (WHO) released fresh
    guidelines for treating children who developed multisystem inflammatory syndrome (MIS-C) after being exposed to the novel coronavirus disease (COVID-19) infection.
  • MIS-C is a condition where various organs of the body are affected by inflammation. The patient develops heart problems, the severity of which may determine the line of treatment. In severe cases, children need intensive care and pacemakers.


  • In picking a name for the newest variant of SARS-CoV-
    2, Omicron, the World Health Organization (WHO) has
    skipped two letters of the Greek alphabet.
  • Omicron, for example, is also known by its more scientific
    designation B.1.1.529, which shows that it has evolved from the B.1 lineage.


  • “Ankylosing Spondylitis (AS) — a disease often confused with mechanical back pain — can show signs in young adults as early as in their 20s or 30s.
  • Contrary to the popular belief, AS is not a man’s disease and impacts both the genders equally.
  • Yet, women continue to overlook the symptoms, which leads to an extremely delayed diagnosis.
  • Early signs could be pain and stiffness in the lower back, especially in the morning or after prolonged inactivity.
  • Prevalent amongst 1 in 500 adults, AS is an irreversible, inflammatory, and autoimmune condition that leads to spinal fusion. The absolute cause of AS is still unknown; however, experts believe that most people with AS have a common gene called HLA-B27.
  • Treatment options and protocols are similar for AS patients of both genders, with (NSAIDs) and physiotherapy being the first line of treatment.


  • Adenovirus causes wide variety of illness in humans. This includes from gastrointestinal infections to common cold.
  • The Adenoviral vector is made by removing the genetic material that could allow the virus to replicate or spread disease. This adenoviral shell is then inserted with genetic instructions on how to target another virus (like COVID-19 virus).
  • An adenovirus looks like a serious vector to the immune system of human body. Thus, the immune system responds seriously. This is why people have been reporting fatigue, fever or sore arm after receiving vaccine dose.
  • The Adenovirus infections are common in humans. Thus, human immune system would have already developed certain antibodies against them. This limits the number of administered doses. This is why several Adenovirus based COVID-19 vaccines are stopped with single shot.




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