At least 10 people have died in the Nipah virus outbreak in the southern Indian state of Kerala, doctors say.
Two others who have tested positive for the virus are critically ill. Some 40 people have been put into quarantine following the deaths.
The virus is hard to diagnose. Symptoms of infection include fever, vomiting and headaches.
Nipah has a mortality rate of 70% and there is no vaccine. It can be transmitted to humans from animals.
Nipah virus is also “top of the list” of 10 priority diseases that the World Health Organization has identified as a potential next major outbreak.
Authorities have ordered emergency measures to control the spread of the infection in Kozhikode, , previously known as Calicut, where the deaths have taken place.
Some 60 blood and body fluid samples of suspected cases have been sent for confirmation to the National Institute of Virology in the western city of Pune, officials said.
Among the dead are three members of one family. A nurse who treated them was among the victims, and is now being hailed as a hero by authorities and in social media.
Lini Puthussery, a mother of two, wrote a note for her husband in a hospital isolation unit saying: “I don’t think I will be able to see you again. Sorry. Please take care of our children.”
The letter is being widely shared on social media.
“Saji Chetta, I am almost on my way. I don’t think I will be able to see you. Sorry. Take care of our children properly. Our innocent child, take him to the gulf. They shouldn’t be alone like our father. Lots of love…” she wrote in the note that has been widely shared on social media and has moved many to tears.