The culling of poultry birds began near India’s eastern border on Tuesday as locals began implementing an order after an epidemic of a strain of bird flu, or avian influenza, was declared by officials in the state of West Bengal.

“Around 51,000 hens and ducks will be culled within a 3-km radius of the affected zone,” said A K Agarwal, secretary of the ARD department, according to the Times of India.

Surveillance will also continue within a 10 kilometer radius of the area, according to the report. The area affected includes 13 villages in the rural Tehatta I subdivision of Nadia district.

The death of 850 birds was reported to local officials on September 14. Samples of the birds tested positive for the H5 strain of avian influenza.

Culling was ordered on Monday after epidemic bird flu was declared.

“There is a huge waterbody in Tehatta which is flocked by migratory birds around this time of the year. They may have brought the virus,” said Nure Alam Chowdhury, the state animal resources development minister, according to the report.

On August 29, the Food and Agriculture Organization of the United Nations warned of a possible major resurgence of the H5N1 Pathogenic Avian Influenza, adding that signs of a mutant strain were spreading in Asia and beyond.

The H5N1virus has infected over 550 people since it first appeared in 2003, killing 331, the agency said citing the World Health Organization.

The 2003 H5N1 has killed or forced the culling of more than 400 million domestic poultry and caused an estimated $20 billion of economic damage, the FAO said.

The peak infection period took place in 2006, when it affected 63 countries. At its peak there were 4000 outbreaks per year. That number dipped to just over 300 in 2008, although that number rose to almost 800 cases in 2010-2011.

"Wild birds may introduce the virus, but peoples' actions in poultry production and marketing spread it," said FAO Chief Veterinary Officer Juan Lubroth at the time of the FAO report.

Recently affected areas have included Israel, the Palestinian Territories, Bulgaria, Romania, Nepal and Mongolia.