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Communicable diseases, animal health and One Health
Infectious disease in people and animals and the surveillance that catches it: outbreaks, zoonoses, neglected tropical diseases, livestock disease, and the international rules for pandemics. Prelims has asked which disease the H1N1 virus is linked to and whether viruses spread only through vectors.
UPSC has asked
- Prelims 2013: whether viruses spread only through biological vectors
Showing 5 of 11 subjects, those that changed from 16 to 31 July 2026.Show all
Chandipura virus
Copy link to Chandipura virusPrelims and Mains
A sandfly bite in a village in Gujarat or Rajasthan can end in brain inflammation, and it is children who are affected. What is still unsettled is how the virus actually reaches them, which is why the investigation is running through animals as well as insects.
- Chandipura virus is spread mainly by sandflies, and causes a fever that can progress to acute encephalitis syndrome, brain inflammation.
- It falls mostly on children.
- At least 22 children had died in Gujarat and Rajasthan by 6 August 2026.
- Mosquitoes, ticks and mites are being tested alongside the sandfly as vectors.
- Cattle, buffaloes and goats are being tested as reservoir hosts, so the National Centre for Disease Control (NCDC), ICMR and the Department of Animal Husbandry went in as one team.
- Testing animals beside people is One Health in practice, the approach that also ties crowded, antibiotic dosed livestock farming to antimicrobial resistance and to the spillover of pathogens.
What changed
6 Aug 2026
The Hindu, 6 Aug 2026: Chandipura virus outbreak in Gujarat and Rajasthan (opens in a new tab)
26 Jul 2026Updatealso in news
- Rajasthan stepped up surveillance after two girls from Dungarpur and Sirohi who died tested positive. The virus is carried by sandflies and mainly affects children under 15, causing acute encephalitis.
Background reading: PIB, 5 Aug 2026: Chandipura virus outbreak: national response team deployed (opens in a new tab)
Influenza surveillance
Copy link to Influenza surveillancePrelims and Mains
The surge was the first real test of the surveillance India built after COVID-19. What it exposed is a system that watches continuously without ever having to declare that anything has begun.
- An integrated command structure was proposed to replace that split.
- Surges are compared fairly by incidence rather than by raw case counts.
- Wastewater surveillance can give early warning of a novel pathogen.
Testing
- Influenza like illness and severe acute respiratory infection (SARI) samples tested year round
- No alert thresholds
Coordination
- Split between ICMR, NCDC and the States
Treatment
- Under 10 per cent of admitted patients get antivirals
What changed
3 Sep 2026
21 Jul 2026Update
- The Viral Research and Diagnostic Laboratory network has grown to 163 laboratories, with four regional sequencing hubs and wastewater surveillance for early detection.
- Dengue is tracked through 887 sentinel hospitals and 27 apex laboratories, and a programme for leptospirosis strengthens surveillance and early antibiotic treatment.
PIB, 21 Jul 2026: Coordination mechanisms between Central and State health authorities during public health emergencies have been strengthened and tested through simulation exercises and mock drills (opens in a new tab) · PIB, 28 Jul 2026: Focused Interventions for Dengue, Malaria, Diarrhoea and Leptospirosis Supported by PPCL, STOP Diarrhoea Campaign and Flood Preparedness Measures (opens in a new tab)
Background reading: Frontline, 8 Sep 2026: Public health is political: Brian Wahl (opens in a new tab)
See also: Influenza A (H1N1)
Dengue serotypes in India
Copy link to Dengue serotypes in IndiaPrelims and Mains
Dengue has four serotypes, and where all four circulate together, a state called hyperendemicity, a person infected with two at once is more likely to develop severe dengue.
What changed
29 Jul 2026New subject
- A two year study by the Indian Council of Medical Research network analysed 6,889 confirmed samples from 25 States and Union Territories. Eight reported all four serotypes circulating together, a state called hyperendemicity, with DENV-2 predominant.
- About 7 per cent of patients carried two or more serotypes at once and were more likely to develop severe dengue.
Amoebic meningoencephalitis
Copy link to Amoebic meningoencephalitisPrelims
Amoebic meningoencephalitis is a rare and usually fatal brain infection caused by free living amoebae in warm fresh water that enter through the nose, reported in Kerala among people who bathe in ponds.
What changed
29 Jul 2026New subjectalso in news
- Kasaragod in Kerala reported a further case in a person who had bathed in a pond. The infection is caused by free living amoebae in warm fresh water that enter through the nose.
The Hindu, 29 Jul 2026