Communicable diseases, animal health and One Health

Prelims and Mains

Chandipura virus is a rhabdovirus related to rabies, carried mainly by sandflies.

• It causes fever that can turn into acute encephalitis, inflammation of the brain, in children, killing within days.
• Outbreaks recur in summer in Gujarat, Maharashtra and Rajasthan.
• Testing animals beside people in an outbreak is One Health in practice.

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.

Prelims 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.

Prelims

Kerala faces recurrent water borne disease: shigellosis, hepatitis A, norovirus, acute diarrhoeal disease and amoebic meningoencephalitis, linked to faecal contamination of domestic wells and ponds.

• Shigella is a rod shaped, gram negative bacterium that spreads by the faeco oral route, and multi drug resistant Shigella is present across India.
• Amoebic meningoencephalitis is a rare and usually fatal brain infection caused by free living amoebae in warm fresh water that enter through the nose.

Prelims and Mains

The Bundibugyo strain is one of several species of Ebola, with a fatality rate of up to 40 per cent and no approved vaccine or treatment.

• The Zaire strain has an approved vaccine, Ervebo, built on the rVSV platform.
• Candidate vaccines against Bundibugyo reuse proven platforms: rVSV, and ChAdOx1, the platform of the Oxford AstraZeneca COVID 19 vaccine.
• Oxford and the Serum Institute of India are developing the ChAdOx1 Bundibugyo vaccine.
• Confirmation needs a strain specific polymerase chain reaction (PCR) test available in few laboratories.
• Rapid tests built for the Zaire species miss cases until viral load is very high, which delays diagnosis and isolation.

Prelims

Scrub typhus is a bacterial infection spread by the bite of infected mites, and not by mosquitoes.

• The bacterium is *Orientia tsutsugamushi, and the carriers are larval mites called chiggers*.
• It does not pass from person to person, and it has no vaccine.
• Its sign is an eschar, a dark scab at the bite, and it is treated with doxycycline or azithromycin.

Prelims and Mains

Disease surveillance is how India watches for outbreaks, through three networks; biological disaster preparedness is how it responds to an epidemic, a pandemic or a deliberate release.

• Influenza A subtypes are named for two surface proteins, haemagglutinin (H) and neuraminidase (N); H1N1 caused the 2009 pandemic and settled into the seasonal mix.

Prelims and Mains

The National Action Plan for Prevention and Control of Zoonoses is built on the One Health approach and names ten priority zoonoses.

• The ten run from anthrax and brucellosis to Nipah, rabies and Zika.
• Each State is to write its own plan on the same lines.

Prelims

Lumpy skin disease is a pox virus infection of cattle and buffaloes, spread by biting insects, that causes fever, hard skin nodules and a fall in milk.

• It does not infect people.
• It reached India in 2019 in West Bengal and Odisha and has not left.
• Control works on the vector as much as the sick animal: ring vaccination around an outbreak, and insect control.
• The vaccine, Lumpi ProVacInd, is indigenous, developed by the Indian Council of Agricultural Research's National Research Centre on Equines at Hisar.

Prelims and Mains

The National Viral Hepatitis Control Programme, launched in 2018, aims to eliminate viral hepatitis as a public health threat by 2030.

• It works through free screening and treatment and the hepatitis B birth dose.

Prelims

The Pathogen Access and Benefit Sharing system links the sharing of pathogens with pandemic potential to the sharing of the vaccines, tests and treatments made from them.

• It is the annex left unfinished when the WHO Pandemic Agreement was adopted in May 2025.

Prelims

India eliminated leprosy as a public health problem nationally in 2005 (prevalence below one per 10,000), but transmission continues in endemic districts.

• The programme's strategy is periodic case detection campaigns, contact tracing and post exposure prophylaxis with single dose rifampicin for healthy contacts.
• Disability is prevented through reconstructive surgery and protective footwear.

Prelims and Mains

The intensified 100 day TB Mukt Bharat Abhiyaan, a campaign against tuberculosis (TB), moves from waiting for patients to active case finding in villages, urban wards and congregate settings.

• It screens through Ayushman Arogya Shivirs, handheld X ray, Truenat and cartridge based nucleic acid amplification tests (CBNAAT).
• Nikshay Mitras give community support, and nutritional support is stressed to cut mortality.