With the source of the Nipah virus outbreak that has caused 14 deaths in Kerala's Kozhikode and Malappuram districts yet to be ascertained, a batch of fresh five samples from fruit bats will be sent on May 30 to the Bhopal-based National Institute of High Security Animal Diseases, said officials.

"The samples of fruit bats have been taken from the place where four deaths on account of Nipah virus from one family took place near here. These samples are being sent through a special messenger," said an official on May 29. The move comes after 21 samples from bats and pigs were sent to the Bhopal lab last week but all tested negative as per the results which came out on May 25.

Those samples were taken from bats, found in the house of a victim from Perambara near here. The victim as well as two of his sons and another relative died after testing positive for Nipah virus. Both sets of samples have been collected from the same place, but from different varieties of bats that are found in common near Moosa's house.

While the number of fresh fever cases have come down, three more patients who tested positive are under treatment at the Kozhikode Medical college hospital. In a related development, Kozhikode police have registered a case after the district medical officer filed a complaint that a fake letter under her name and style is being widely circulated indicating that no one should eat chicken, as it has been found to spread Nipah virus.