Several airports across Asia have stepped up health surveillance and passenger screening measures following an outbreak of the Nipah virus in an Indian state, authorities and media reports said.

Five confirmed cases of the virus were reported in India’s West Bengal state, prompting countries and territories including Thailand, Nepal and Taiwan to strengthen precautionary measures at airports, according to a report by Asharq.

Nipah is a zoonotic virus that is primarily transmitted to humans from infected pigs or bats, but it can also spread through close person-to-person contact, the World Health Organization says.

Health authorities in the affected countries said no local cases have been detected so far, adding that the measures are aimed at prevention and early detection.