UPDATE 2-Tests prove new bird flu cases in east India state

(Adds details, byline)

By Sujoy Dhar

KOLKATA, India, Dec 15 (Reuters) - Laboratory tests on dead birds have proven a new outbreak of the H5N1 bird flu virus in the eastern Indian state of West Bengal, a state government official said on Monday.

"The laboratory test in Bhopal has confirmed the presence of the H5N1 virus in the dead birds," Sridhar Ghosh, the senior official in West Bengal's Malda district, told Reuters.

Ghosh said the virus had been found in three dead birds tested in a laboratory in the central Indian city of Bhopal.

Indian authorities are already culling hundreds of thousands of birds in the northeastern state of Assam, where health authorities are also monitoring about 100 people who had shown signs of the virus.

Those patients in Assam's Guwahati, the main city in the region, were suffering from fever and respiratory infections, symptoms of the H5N1 bird flu virus in humans.

There have been no confirmed human cases of H5N1 among those patients being monitored nor at any other time in India.

But experts fear the H5N1 virus might mutate or combine with the highly contagious seasonal influenza virus and spark a pandemic that could kill millions of people.