New Delhi, Feb. 4: The “worst” phase of Bengal’s bird flu outbreak may be over, the Centre said today.

But officials added that mopping up birds that escaped culling could take a month and affected districts would need to be poultry-free for 90 days.

“Perhaps, the worst is over,” said animal husbandry secretary Pradip Kumar. “We haven’t seen new districts affected nor have any blocks been added to already affected districts. There is no evidence of avian influenza from any other part of the country.”

Teams are now combing households in villages for chickens and ducks that have survived the culling. In some areas, the number of residual birds could run into hundreds, he said.

But even after the mop-up and disinfection, no poultry would be allowed in the zones where culling has been done for three months.

The 90-day ban on poultry in the affected areas will prevent any virus that might be lingering in the environment from getting a fresh chance to infect and multiply in birds, a senior microbiologist said.

However, during this period, processed (cooked) chicken could be bought and consumed, said S. Bandopadhyay, the animal husbandry commissioner. Unlike bacteria, a virus cannot infect dead organisms.

Poultry consumption has been hit even outside the affected zones. But public health and animal husbandry officials have asserted since the beginning of the outbreak that poultry products cooked at temperatures above 70°C could be consumed.

Kumar said the Centre had released an additional Rs 5 crore for compensating poultry owners and for culling operations in Bengal. The Centre had earlier provided Rs 3.5 crore.

Officials said nearly 2.1 million birds would have to be culled in neighbouring states to create a 5km zone depopulated of poultry in adjoining Bengal districts.

Assam today began culling poultry in two districts bordering Bengal, but culling has yet to begin in Jharkhand, Bihar and Orissa.

There have been concerns about resistance in Orissa to culling of healthy birds.