More than 100,000 chickens and ducks have been be slaughtered over the weekend in around 20 villages, after one of them, just 35 km of Guwahati, was hit by bird flu.
Authorities are worried about a new outbreak after some poultry deaths were reported in Palasbari.
"It is around between two to three lakh. About two lakh more need to be culled," said S L Mewara, the state's commissioner of veterinary and animal husbandry department.
The virus has now spread to Barpeta and Nalbari districts besides Kamrup district.
Samples sent earlier to laboratories in Bhopal had tested positive or H5N1 avian influenza.
The State Government ordered culling operations and officers began going from house to house urging villagers to hand over their poultry.
Sale and movement of poultry in and around Guwahati has been prohibited and precautionary measures stepped up in other parts of the state.
Migratory birds from Siberia and Myanmar are believed to be the carrier agent of the flu to Assam. ndia has not reported any human infections so far, though the first outbreak in poultry was reported in 2006 in Maharashtra.