As the death toll in the virus-induced fever in north Kerala rises to nine, the National Virology Institute in Pune has confirmed that the deceased were infected with Nipah virus (NiV). This is the first time the virus, which has high fatality rate and spreads mainly through bats, pigs and other animals, has been detected in the state.
The Union Health Ministry has rushed a team of experts to assist the state that is struggling to cope with the outbreak. Here’s all you need to know about the virus:
Nipah virus (NiV) infection is a newly-emerging zoonosis (a disease which can be transmitted to humans from animals) that causes severe disease in both animals and humans. The natural host of the virus are fruit bats of the Pteropodidae Family, Pteropus genus.
NiV was first identified during an outbreak of disease that took place in Kampung Sungai Nipah, Malaysia in 1998. On this occasion, pigs were the intermediate hosts. However, in subsequent NiV outbreaks, there were no intermediate hosts. In Bangladesh in 2004, humans became infected with NiV as a result of consuming date palm sap that had been contaminated by infected fruit bats.
OUTBREAKS IN INDIA
Human-to-human transmission has also been documented, including in a hospital setting. India confirmed its first Nipah outbreak in Siliguri, West Bengal, in 2001, with 66 cases and 45 deaths. A second outbreak in Nadia district in 2007 led to the deaths of all the five persons infected. The death rate in India is a high 70%, with 50 of the 71 people infected dying during the two outbreaks in West Bengal.
This is the first Nipah outbreak in Kerala.
The viruses jump the species barrier and infect a secondary animal host, transmission takes place through direct contact with infected bats, pigs, or from other NiV-infected people and people have been also cautioned that they should not consume fruits that have fallen on to the ground.
NiV infection in humans has a range of clinical presentations, from asymptomatic infection to acute respiratory syndrome and fatal encephalitis. NiV is also capable of causing disease in pigs and other domestic animals. Nipah virus primarily causes an encephalitic syndrome with a high mortality rate. The characteristic MRI abnormalities are multiple, small (less than 5 mm), asymmetric focal lesions in the subcortical and deep white matter without surrounding edema.
There is no vaccine for either humans or animals. The primary treatment for human cases is intensive supportive care
Nipah virus infection can be prevented by avoiding exposure to sick pigs and bats in endemic areas and not drinking raw date palm sap and not consuming fruits that have fallen from trees.