Nipah virus is a deadly virus transmitted from bats to humans that causes respiratory illness and fatal encephalitis. The virus was first identified during an 1998 outbreak in Malaysia. It typically has an incubation period of 3-14 days with initial symptoms including fever, headache and drowsiness that can progress to coma within 48 hours. There is no approved vaccine or treatment. Outbreaks have occurred in Malaysia, Singapore, Bangladesh and India with high mortality rates. The natural host is fruit bats and it can be transmitted via contaminated food or bodily fluids.