Question
Nipah virus
Answer
Nipah virus is a highly pathogenic, emerging zoonotic paramyxovirus (genus Henipavirus), causing severe encephalitis and respiratory illness with a high case-fatality rate, of particular regional significance given recurrent outbreaks in Kerala, India and Bangladesh.
Natural reservoir and transmission: fruit bats (Pteropus species, “flying foxes”) are the natural reservoir; transmission to humans occurs via:
- Intermediate amplifying hosts — classically pigs in the original 1998–99 Malaysia outbreak (direct contact with infected pigs).
- Contaminated food — consumption of raw date palm sap contaminated by bat excreta/saliva, the predominant route in Bangladesh and the Kerala outbreaks.
- Direct bat-to-human contact or human-to-human transmission — via close contact with infected patients’ bodily secretions, an important route in some outbreaks (including in Kerala), of particular concern for nosocomial spread among healthcare workers.
Clinical features: presents with fever, headache, and rapidly progressive encephalitis — altered consciousness, seizures — with a high case-fatality rate (up to 40–75% in various outbreaks); can also cause severe respiratory illness/ARDS.
Laboratory diagnosis: RT-PCR (on throat/nasal swab, CSF, urine, or blood) — the primary diagnostic method; serology (IgM/IgG ELISA); viral isolation requires high-biosafety-level (BSL-4) laboratory facilities given the severity and transmissibility of the virus.
Management/prevention: no specific antiviral treatment or licensed vaccine is currently widely available (though ribavirin and monoclonal antibody therapies have been explored); management is supportive; strict barrier nursing/isolation precautions for suspected/confirmed cases, given the risk of human-to-human transmission; avoiding consumption of raw date palm sap and unprotected contact with bats/sick pigs in endemic areas; robust outbreak surveillance and rapid containment response, given the virus’s high mortality and pandemic-potential concern (it is on the WHO’s priority pathogen list for pandemic preparedness).