The institute said the bats died of some other reason.
Panic spread as several bats were found dead at Government Senior Secondary School in Barmapapri this week.
He has advised people not to panic about the Nipah virus, adding all medical colleges in the state are prepared to deal with the situation, if it occurs.
Get the latest election news, live updates and election schedule for Lok Sabha Elections 2019 on ndtv.com/elections. Like us on Facebook or follow us on Twitter and Instagram for updates from each of the 543 parliamentary seats for the 2019 Indian general elections. Election results will be out on May 23.