A swine flu outbreak in India has claimed 12 lives since the beginning of this month and more than a hundred people have been infected so far.

The source of the outbreak has not yet been determined, but India's Health Ministry has said it is being contained and urged people not to panic.

The health ministry is monitoring the situation, and there is no cause for worry. The states where cases had been reported have been advised to step up surveillance to control the further spread of the virus, Health Secretary P.K. Pradhan told the Press Trust of India news agency, BBC News reported.

This is the second outbreak of the H1N1 virus, which last emerged in India in 2009. The first epidemic there claimed more than 450 lives, and over 13,000 people were infected.

Health Ministry officials are still trying to determine why the virus has re-emerged, but medical professionals say the outbreak could eventually die down after surging.

Last year globally, swine flu was at an ebb, National Institute of Virology director Dr. A.C. Mishra told the Indian Express newspaper, BBC reported. While short spurts are being recorded in other countries this year, it could well be a short spell where the virus will surge and then die down.

The H1N1 virus originated in Mexico around April 2009, and it spread globally, taking 17,000 lives, the Telegraph reported. The World Health Organization declared an end to the pandemic in August 2010.

A number of cases have been reported around the globe during the past couple of years, but India's recent outbreak has been the largest since the 2009 pandemic.