Since December 2025, two confirmed cases of the virus have been reported in West Bengal, India’s health ministry said on Wednesday. Here’s what we know:What is the Nipah virus? The Nipah virus (NiV) is a zoonotic virus – a disease transmitted from animals such as fruit bats and flying foxes to humans. “The case fatality rate is high, between 40 percent and 75 percent, among people infected with the Nipah virus,” Abbas told Al Jazeera. AdvertisementThe University of Oxford has been conducting clinical trials in Bangladesh to test a Nipah virus vaccine and launched the second phase of trials in December 2025.