With six more deaths of children reported since Tuesday, the toll in the viral fever outbreak in Andhra Pradesh on Wednesday mounted to 116.

The state government, meanwhile, has launched a massive sanitation drive to prevent the spread of the disease. Anti-mosquito drives have been launched on a large scale, state government sources said.

So far 209 cases of suspected viral encephalitis have been reported, official sources said.

Andhra Pradesh Minister for Medical and Health Dr Sivaprasada Rao visited the worst affected districts and was touring Guntur to oversee the sanitation works.

Departments of medical and health, panchayat raj, revenue, animal husbandry and others will evolve coordination programmes to tackle the spread of the virus. The state has earmarked Rs 2.5 million per district to carry out the action plan.

Warangal recorded the highest 82 cases and 42 deaths, while Karimnagar accounted for 43 deaths of the 67 cases reported, the sources said.

Experts from the National Institute of Virology, Pune and National Institute of Communicable Diseases, Delhi have drawn a blank and could not pinpoint the cause of the disease, they added.