Scientists spot reservoir of Nipah virus

Medical researchers have reported the discovery of the first reservoir of Nipah virus in the wild in India, weeks after the dreaded pathogen killed 17 people in Kerala.

The virus has been found in Cooch Behar — a district in the northern part of West Bengal — and Dhubri in western Assam, after a team from National Institute of Virology, Pune, sampled more than 100 fruit-eating bats from the region.

Between January 2001 and January 2013, there were 18 Nipah outbreaks in India and Bangladesh.

In three cases, each of the infected persons died and in five occasions, more than 80% infected individuals died.

Only in two outbreaks, the fatality was less than 40%.

With little evidence of a natural reservoir of the virus in India, the researchers decided to look into some of the districts bordering Bangladesh where Nipah appeared in regular periodicity.

They obtained permissions from the forest department and captured 107 bats — 60 from Dhubri (Assam), 39 from Cooch Behar and eight from Jalpaiguri — both in West Bengal.

Laboratory tests revealed the presence of the virus in nine of the 107 samples, confirming its presence in the wild in India.

"During the present study, it was observed that large colonies and roosts of Pteropus giganteus bats were present in close proximity of human settlements in Dhubri and Cooch Behar. This signifies higher and easier chances of virus spillover from bats to human population.

"The presence of Nipah virus in the bat population in a previously unexplored region is a matter of serious concern,” the scientists reported in the latest issue of the Indian Journal of Medical Research published by the Indian Council of Medical Research.

Pteropus bats are known to be a natural reservoir for Nipah virus. But in the two outbreaks in India in 2002 and 2007 in Nadia and Siliguri in West Bengal, the role of these bats couldn't be ascertained.

NIV's only previous success was to identify the virus in one bat out of 140 sampled from Maharashtra and West Bengal between 2009 and 2010.

The discovery coincided with ICMR's confirmation on fruit bats being the primary source of the Nipah outbreak in Kerala's Kozhikode and Malappuram districts.