Kozhikode, Malappuram, Wayanad and Kannur districts in Kerala state are currently grappling with a newly emerging zoonosis caused by Nipah virus (NiV) which has claimed 12 lives so far. The virus gets its name from the place called Kampung Sungai Nipah in Malaysia where it was first identified in 1998 in domestic pigs.
The disease first appeared in human beings in 2001 in Bangladesh and the infection was a result of consuming date palm sap that was contaminated by infected fruit bats. In India, the disease was first reported in 2001 and then in 2007. Seventy-one cases with 50 deaths were reported during the two outbreaks. Both the times, the disease was reported in areas of West Bengal bordering Bangladesh.
NiV outbreaks mostly occur between the period of December and May. The virus spreads through fruit bats (Pteropodidae Pteropus) and can both affect humans as well as domestic animals including dogs, cats, goats, horses and sheep. There is no vaccine for NiV and the primary treatment is intensive supportive care. The virus has a mortality rate between 40-70% and fatality has been as high as 100% in some outbreaks, according to World Health Organisation.
NiV infection is associated with encephalitis (inflammation of the brain). According to Centres for Disease control and Prevention, USA, after exposure and an incubation period of 5-14 days, illness presents with 3-14 days of fever and headache, followed by drowsiness, disorientation which can progress to coma within 24-48 hours and death. Some patients have a respiratory illness during the early part of their infections, and other patients showing severe neurological signs showed also pulmonary signs. The virus can be transferred from a human through close contact, body fluids, saliva and cough.
Indonesia, Thailand and Timor-Leste have identified antibodies against NiV in the bat population and the source of the virus has been isolated. NiV cases tend to occur in a cluster or as an outbreak, although 18% of cases in Bangladesh were isolated.
Though surveillance has been has been stepped-up in the states bordering Kerala and travel advisories to NiV infested areas have been issued by government agencies, readers are cautioned to seek immediate medical attention should they experience flu-like symptoms.
