At least two people in West Bengal have been infected with the Nipah virus.
The cases were identified in the North 24 Parganas district of the state.
Over 120 people have been kept in quarantine following the outbreak.
A wedding in the Nadia district of WB is considered the likely source of the exposure.
One of the affected persons, a nurse, reportedly consumed raw date palm sap, also called khejurer rosh, at the event.
It's a traditional winter drink, but it is susceptible to fruit bat saliva, urine or droppings of fruit bats.
Palm sap has been a cause of the Nipah cases in the region in 2007 as well.
Authorities have stepped up surveillance and containment measures, urging the public to stay vigilant and report symptoms early.