Out of every 100 Indians, who tested positive for swine flu recently, 22 were from Tamil Nadu. This marks a five-fold increase compared to around four per cent till about August 2010.

The Union Ministry of Health and Family welfare said that out of the 1,155 persons tested across India and found to be positive for H1N1 between September 20 to October 1,1 249 were from TN.

The primary reason for the spurt was the change in climate. “The onset of Twinter is normally conducive for transmission of the virus. The reporting system has also been strengthened resulting in more cases coming to light”, said R Porkaipandian, director for public health and preventive medicine.

Further, there are borderline cases of the flu that are not recognized as confirmed ones, as a result of which there is question mark on the credibility of figures said Porkaipandian.