Fresh cases of bird flu have been detected in two Murshidabad villages, weeks after the Bengal government said culling operations were over and lifted the state-wide ban on selling chickens and ducks.

District magistrate Subir Bhadra confirmed tonight that samples sent to the National Animal Research Laboratory in Bhopal from the two villages, Nayamukundapur and Bothra, had tested positive.

Bhadra said about 60 rapid response teams would be trained tomorrow so they could start culling chickens and ducks in the affected areas from Monday morning.

The samples were sent three days back after 600 chickens died in Nayamukundapur in Raghunathgunj Block II, about 50km from Behrampore, and over 300 perished in Bothra in Murshidabad-Jiagunj block, about 20km from the district headquarters.

In Calcutta, animal resource development minister Anisur Rahman said he had heard about the fresh outbreak.

"We didn´t carry out culling operations in two freshly affected blocks of Murshidabad in January when bird flu first hit Bengal. We shall begin culling there in full swing from Monday."

The minister said he would visit the affected blocks tomorrow or on Monday after briefing the chief minister. "The situation is indeed worrisome," he added.

The state government had ordered culling operations from mid-January after 16 of Bengal’s 19 districts were found to have been affected by the deadly H5N1 strain of avian influenza.

Nearly 40 lakh chickens and ducks were culled till February 5. The administration lifted the ban on sale of chickens and ducks seven days later, though mop-up operations are still on in pockets.

On February 22, the government resumed culling in Murshidabad and Birbhum after a central government report said the job was incomplete in parts of the two districts.

An official in Murshidabad, about 220km from Calcutta, said the administration launched a campaign tonight over loudspeakers, asking people to cooperate and hand over their poultry when culling teams visit their homes on Monday.