NEW DELHI, Sept. 14 (Xinhua) -- The mystery fever death toll in the northern Indian state of Uttar Pradesh has risen to 42, officials said Friday.

"With six more deaths in the last three days, the number of dead due to mystery fever in the state now stands at 42," a senior health official said.

"All these deaths were reported from the state's Bareilly and Badaun districts in the past fortnight. And now three more deaths have been reported from each of these districts," he added.

The state government has formed high-level medical teams to look into the cases and a central team is also looking into the deaths.

State Health Minister Sidharth Nath Singh recently said the government has ordered a "death audit" in Uttar Pradesh.

"Preventive and remedial actions have been initiated," the state's health director Mithilesh Chaturvedi told the media Tuesday.