Tests have ruled out bats being behind the spread of the Nipah virus that took 12 lives in Kerala's Kozhikode and Malappuram districts, officials said on May 25.

A total of 21 samples from bats and pigs were sent to the High Security Animal Diseases laboratory at Bhopal but all turned out negative according to the results, obtained late May 25 evening, said officials. Early this week, a team led by Central Animal Husbandry Commissioner S.P. Suresh, after examination of animals in the affected areas near here, said no incidence of Nipah virus had been identified in animals and it was the humans who had been affected.

The samples sent to Bhopal included those taken from bats found in the house of a disease victim in the worst-affected Perambara village. His two sons and another relative also succumbed. All the 21 samples were collected from in and nearby Perambara. Transmission of NiV takes place through direct contact with infected bats, pigs or from other NiV-infected people. With the results showing that this virus has not come from bats, the authorities have now decided to conduct more tests to locate its source.