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Communicable diseases, animal health and One Health

Infectious diseases in people and animals: outbreaks, surveillance, India's disease programmes, and the One Health approach that joins human, animal and environmental health. Prelims has asked which disease the H1N1 virus is linked to and whether viruses spread only through vectors.

Foundation note: The diseases Prelims asks: pathogen, vector, programme

Showing 1 of 13 articles, those that changed from 1 to 31 August 2026.Show all

Outbreaks in people

Leptospirosis

Prelims and Mains

Leptospirosis is a bacterial zoonosis caused by Leptospira from the urine of rodents and other animals.

The bacteria survive in standing water and soil and enter through cuts or mucous membranes, so the disease peaks after monsoon floods among farmers, cleaners and construction workers.
It does not pass from person to person.
Treated early with antibiotics it is mild; diagnosed late it goes on to pulmonary haemorrhage and multi organ failure, which is what kills.

What changed

3 Aug 2026BriefIt killed 50 people in Kerala in July 2026, the State's deadliest communicable disease that month, and late diagnosis was named as the cause. The Hindu, 3 Aug 2026: Why is Kerala facing high leptospirosis mortality? | Explained (opens in a new tab)

Lumpy skin disease: A viral disease of cattle and buffaloes that causes fever and hard nodules in the skin.

Ring vaccination: Vaccinating every susceptible animal in a ring around an outbreak, building a barrier of immunity that stops the disease spreading outward.

One Health: Treating human, animal and environmental health as one linked problem rather than three separate ones.

Incidence: New cases in a population over a set period, which allows fair comparison between places of different size.

Biological disaster: A disaster caused by living organisms or their toxins: an epidemic, a pandemic, or a deliberate release of a pathogen.

National Disaster Management Plan: The country's plan under the Disaster Management Act, 2005, setting out who does what in prevention, mitigation, response and recovery.

BSL 3: A Biosafety Level 3 laboratory, built to handle dangerous airborne pathogens.

Shigellosis: A diarrhoeal disease caused by Shigella bacteria, marked by fever, cramps and bloody diarrhoea.

Eschar: A dark scab at the site of the mite's bite.

Chigger: The larval mite that spreads scrub typhus.

Also filed elsewhere

Dengue vaccines: Qdenga, DengiAll and antibody dependent enhancement · on Vaccines and immunisation
Dengue has four serotypes, and antibodies from a first infection can help a different serotype enter cells in a second, which is antibody dependent enhancement and is why dengue vaccines are hard to design: vaccination raises type specific antibodies, which block one serotype, and cross reactive antibodies, which block all four only at high levels and can enhance a new infection into severe dengue once they wane.