In a major relief to Kerala, all the six suspected Nipah cases whose samples were sent for tests on Wednesday were found to be negative.

Samples from two more persons were on Thursday sent for tests to the Pune National Institute of Virology and about 300 people are still under observation.

With Nipah recurring in the state for the second consecutive year, the Kerala government decided to conduct research to identify the exact reason for the disease in Kerala.

State Health Minister K K Shylaja will soon hold talks with Union Health Minister Harsh Vardhan seeking the Centre's support in this regard as well as for setting up a virology institute with advanced facilities in Kerala.

The infection source could not be traced yet.

Meanwhile, the lone person who was so far confirmed to be infected by the Nipah virus is recovering at a private hospital in Kochi.

He reportedly spoke to his relatives over the intercom facility of the hospital.

Health department officials hope to get vital information from him regarding the sources of the virus.

Chief Minister Pinarayi Vijayan, who held a meeting with top officials and people's representatives to review the situation in the state, said that Kerala would be on high alert until it is fully ensured that there is no chance of anyone getting infected.

He also said that the recurrence of the viral infection was a cause of concern and research would be initiated to find the exact cause, even as the preliminary assumption is that the disease is spread through fruit bats and added that research would also be initiated to find the cause for the recurrence of the disease in Kerala.