Roosters are displayed at a wholesale market in the eastern Indian city of Kolkata, January 17, 2008. Bird flu spread to two new districts in an eastern Indian state, officials confirmed on Saturday, as veterinary staff struggled to cull thousands of birds in the face of resistance from farmers. [Photo: Reuters]

Bird flu spread to two new districts in an eastern Indian state, officials confirmed on Saturday, as veterinary staff struggled to cull thousands of birds in the face of resistance from farmers.

The H5N1 virus was found in dead birds in Burdwan and Nadia, taking to five the number of infected districts in West Bengal state.

The virus was also spreading to new areas within already infected districts.

India, which is witnessing its fourth bird flu outbreak in poultry since 2006, has not reported any human infection.

Officials said they were immediately extending culling operations to the newly affected areas. West Bengal began culling more than 400,000 chickens and ducks in three districts this week.

So far, only about 50,000 birds had been culled.

"This news is indeed distressing and we are looking to intensify culling in both districts from tomorrow," Anisur Rahaman, West Bengal's animal resources minister, said.

But containment efforts continued to be hampered because farmers insisted that their chickens and ducks were healthy and refused to hand them over for culling.

Scant respect for hygiene among poor and illiterate villagers was also a stumbling block, said veterinary volunteers who collected dead birds dumped in village wells and ponds by villagers ignorant about the risks from the H5N1 virus.

Rahaman asked health workers to intensify an awareness drive.

Health workers were watching for people with flu symptoms in the affected areas.

The virus has killed more than 45,000 chickens and birds in West Bengal in the past two weeks.

Bird flu has begun taking a toll on India's poultry business with Oman banning the import of all Indian poultry products. Domestic sales have also been affected.