A swine flu outbreak in Rajasthan has killed 76 people so far this year, government officials said on Wednesday.

Colder weather has worsened the seasonal outbreak of the H1N1 virus, with Rajasthan recording more than a third of all swine flu deaths in India, officials said.

Rajasthan's cities, with their imposing fortresses and palaces, attract many overseas tourists, although officials said there no reports of any of them catching the virus.

More than 8,700 people in Rajasthan have been screened for H1N1 this year, and 1,976 had tested positive by Tuesday, a state health department spokesman told Reuters.

The worst affected area was Jodhpur district, which recorded 23 of the 76 deaths in the state so far this month.

Rajasthan reported 705 cases of swine flu and 53 deaths in the month of January last year.

A team from the National Centre for Disease Control (NCDC) arrived in Jodhpur on Tuesday and will spend two days to investigate the outbreak, the spokesman said.

Nationwide, 4,571 cases of H1N1 virus and 169 deaths were reported by Jan. 27, according to NCDC data.

Doctors said that the severity of the current outbreak in Rajasthan was partly due to colder than normal weather.

"It's a seasonal disease and the weather is conducive to viral multiplication," said Raman Sharma, senior professor at SMS Medical College in Jaipur.