Kolkata: Bird flu has come knocking at Kolkata's doorstep as the avian flu has spread to Hoogly and Cooch Behar districts, taking the number of affected districts in the state to nine.

Hoogly is just an hour away from the West Bengal capital city.

Meanwhile, the Bihar Government has ordered culling of chicken in six panchayat areas of Katihar district adjacent to bird flu-affected Malda district of West Bengal The Bihar government has already banned import of poultry from the neighbouring state.

"We have put a blanket ban on import of birds from West Bengal in the wake of reports of the dreaded H5N1 virus spreading there," Deputy Chief Minister Sushil Kumar Modi, who is also holding the portfolio of Animal and Fishery Resources, said.

In West Bengal, the authorities have now set a target of culling three lakh chicken daily. Over the last couple of days avian flu has been confirmed in North and South 24 Parganas, Nadia, West Midnapur, Birbhum, Malda and Dinajpur.

Around 20 million people live in these infected areas. "Samples of chicken sent from Cooch Behar and Hooghly districts on Tuesday tested positive at the Highrisk Security Disease Laboratory (HSDL) in Bhopal," West Bengal Animal Resources Development Minister Anisur Rahaman said.

"We have been informed by the Centre. Steps will be taken accordingly," he said.

The situation is increasingly becoming worrisome in West Bengal, with a large backyard poultry population that mingles freely with ducks and wild birds. "Steps are being taken to officially notify both Cooch Behar and Hooghly districts bird flu affected, for the next course of action including culling," Rahaman said.

The samples which tested positive were from Dinhata in Cooch Behar district and Balagarh in Hooghly district, he said. There was, however, no case of humans beings being affected, the minister said. The target of culling which was set at 20 lakh was also likely to increase, he said.

Culling has begun in Hooghly's Balagarh and culling teams have been increased from 60 to 400. The daily target now stands at three lakh, he said. About 150 technical teams from eight states, including Haryana, Assam, Maharashtra, Orissa and Jharkhand would soon join to monitor the culling.

West Bengal's border with neighbouring states has already been sealed, the minister said.