INDIA began a fresh round of tests to trace the origin of a rare brain-damaging virus that has killed 13 people, a health official said on Monday (28), as initial tests on animals suspected of carrying the Nipah virus showed no sign of the disease. All animal samples, including those from bats, cattle, goats and pigs from the southern state of Kerala, which were sent to the National Institute of High Security Animal Diseases, in Bhopal, Madhya Pradesh, were negative for Nipah, said animal husbandry officer A Mohandas. The department was now collecting samples of fruit bats from Perambra, the suspected epicentre of the infection and nearby areas, Mohandas added. Separately, tests run on dead bats in the northern state of Himachal Pradesh were negative for Nipah, an official there said. Of some 116 suspected cases sent for testing in recent weeks, 15 have been confirmed as Nipah, the Kerala government said on its website on Monday. Thirteen of those 15 people have died and two are undergoing treatment. No confirmed cases of the virus have yet been found outside Kerala, despite fears it has spread. Some neighbouring states including Maharashtra, Telangana and Karnataka have sent samples for testing of people who reported Nipah-like symptoms in the last few days. There is no vaccine for the virus, which is spread through body fluids and can cause encephalitis, or inflammation of the brain, the World Health Organization said. The usual treatment is to provide supportive care. The Coalition for Epidemic Preparedness Innovations (CEPI) said last week that Profectus BioSciences and Emergent BioSolutions would receive up to $25 million to accelerate work on a vaccine against Nipah virus.