KOCHI: Are fruit bats alone to be blamed for the recent spread of Nipah virus in Kerala?
While initial findings on last year’s Nipah outbreak in North Kerala and this year’s case reported from central Kerala blame fruit bats for the spread of the deadly disease, new findings by scientists from leading institutions across the world reveal that two species of insect bats are also likely to be carriers of the virus. The two species were identified as the yellow bat (scotophilus kuhlii) and the roundleaf bat (hipposideros pomona).
Speaking to Express, Thrissur-based researcher P O Nameer of the Centre for Wildlife Studies, Kerala Agricultural University (KAU), the lone Indian scientist in the global research team on Nipah, said that out of 112 bat species in India, 11 were identified through serological tests (serum-based tests) as carriers of Nipah virus.
“Out of the 11, seven species are present in Kerala, of which five are fruit bats and two insect bats. Since diversity-wise, insect bats are large in number, one cannot rule out the possibility of that species being responsible for the recent Nipah case,” he said.
Nameer has been researching on ecological aspects of bats for over two decades. “As far as Kerala is concerned, since most of the virus detected bat species are present, there should be a systematic and broader study to firmly conclude the source and route of spread of virus to humans,” said Nameer. “PCR-based tests conducted using genes of bats revealed Nipah presence only in fruit bat or the Indian Flying Fox (Pteropus medius).
National Institute of Virology (NIV) has collected samples from only the Indian Flying fox in Kerala. Samples of these 11 bat species were tested globally but it is yet to be done in India. For conclusive results, PCR tests must be conducted on more samples collected from within India to know whether other species in India are also carriers of the Nipah virus,” said Nameer.
The team has conducted literature-based studies on Nipah outbreaks in Malaysia, Bangladesh, West Bengal and Kerala.“We intend to conduct a detailed monitoring of bats from within Indian subcontinent, with particular emphasis on those found in Kerala. We have submitted a proposal to the state Health Department, for collecting samples and conducting further research,” he said.
The global research team includes Raina K Plowright, Daniel E Crowley and Alex D Washburne of Montana State University, Daniel J Becker, University of Georgia, Athens, Barbara A Han and Tao Huang of Cary Institute of Ecosystem Studies, P O Nameer, Kerala Agricultural University, and Emily S Gurley, John Hopkins Bloomberg School of Public Health.
Key findings