Lucknow, Aug 12 - Three more people tested positive for swine flu in Uttar Pradesh Wednesday, taking the toll of those affected by the viral disease in the country's most populated state to 15.

'The three fresh cases were detected out of the 17 samples we received on Tuesday afternoon,' disclosed T.N. Dhole, head of microbiology at the Sanjay Gandhi Post-Graduate Institute of Medical Sciences in Lucknow, the state's only authorised centre for testing the HINI virus.

While one of these patients belongs to Lucknow, the other two are from Kanpur, about 80 km from here.

As many as 11 of the 50 samples referred to the centre on Tuesday had also tested positive, with eight being from a single household.

'The fact that eight of the 11 positive cases were from the family of a former Congress leader, whose five-year-old grandson was the first case to be detected positive, shows how infectious and contagious is the virus,' Dhole pointed out.