The bird flu scare on Thursday gripped Darjeeling where 38 chicken were found dead even as culling operations continued in the 13 affected districts of West Bengal.

Darjeeling Magistrate Rajesh Pandey said 38 chicken died at Takdah village of Darjeeling district in north Bengal on Wednesday night.

Blood samples have been sent to a laboratory for testing and the administration will chalk out an action plan after getting the result, he said.

As many as 5.80 lakh birds have been culled in Murshidabad district so far with 50,000 remaining to be eliminated, said District Magistrate Subir Bhadra.

Culling was mostly done in Samserganj, Beldanga and Kandi block areas.

Ninety per cent culling was over in West Midnapore district where bird flu was spotted in Debra block, district officials said.

However, rains and intense cold were hampering the culling work, they said.

Meanwhile, the state animal husbandry ministry has raised the culling target to 27 lakh following the death of about 4,000 chicken in North 24 Parganas district bordering Kolkata on Wednesday.

Although the district was not yet declared affected, culling operation has been undertaken as a preventive measure.

"As the target area is increasing every day it is impossible to say how many chicken will have to be killed," Animal Resources Development minister Anisur Rehman said.

The minister said so far there was no case of human infection. "We have sent more than 3,500 human samples and none have tested positive," Rehman added.