Nipah virus is a dangerous infection spread mainly by fruit bats, and sometimes through contaminated food or close contact with infected people. First identified in Malaysia in 1999, it has caused outbreaks in Bangladesh and India, including Kerala. Symptoms start with fever, headache and vomiting, and can progress to breathing trouble and brain swelling. The fatality rate in past outbreaks has been high, between 40 and 75 percent. There is no specific medicine or vaccine; treatment focuses on supportive care. The virus spreads when people eat fruit or drink sap contaminated by bats, or through close contact with an infected person’s body fluids. Precautions include avoiding raw date palm sap, washing fruit well, and isolating suspected cases quickly. Health workers use protective gear when handling patients. After two nurses tested positive in West Bengal this month, both later tested negative and improved. About 200 contacts were placed under observation. The WHO says travel restrictions are not needed.