Bangladesh's authorities have culled about 13,000 chickens so far this year following fresh outbreak of bird flu last month, officials said Monday.

Ataur Rahman, a government's bird flu control room official, told Xinhua Monday, "Some 12,789 chickens were culled so far this year after detecting avian influenza in some commercial farms."

Of total, he said, "Some 9,526 birds, including 8,821 in a commercial firm in Dhaka, were culled in the first week of this month."

Fresh outbreak of bird flu was detected in Bangladesh in January with arrival of winter season when the authorities said that they culled 3,263 chickens in three commercial farms in the country's two northwestern districts -- Joypurhat and Sirajgonj.

Director General of Bangladesh's Fisheries and Live Stock Department, Habibur Rahman, had earlier told Xinhua that the department has strengthened its surveillance to contain further spread of the infectious disease.

"We've taken special steps like motivating farmers to adopt preventive measures since the disease found to reemerge last month to contain its outbreak," he said.

According to the control room information, bird flu has so far spread to four districts of the South Asian country including its capital Dhaka this year since its resurrection last month.

The control room official, however, expected that there will not be massive outbreak of the disease this time, saying, "We're near to the end of dangerous period meaning winter season which is the high time for outbreak of the disease."

With the rise of temperature in March and April, director of the government's Influenza Preparedness and Response Project Nazrul Islam said risk factors of bird flu disease will continue to ease off in Bangladesh.

The bird flu was first detected in Bangladesh in a poultry farm near capital Dhaka in March 2007. The situation deteriorated later on as the virus spread fast across the country which was reported in 47 districts between December 2007 and March 2008.

About 50 percent of the country's 150,000 poultry farms were closed and more than 1.5 million chickens, ducks and pigeons were culled as of the end of March, 2008 in which the Bangladesh Poultry Industries Association (BPIA) estimated a loss of about 75 billion taka (about 1.07 billion U.S. dollars).

Following fresh outbreak of the bird flu this year, an official of the BPIA on condition of anonymity said a number of poultry farmers in the country have already dwindled their production being afraid of incurring losses further.

Bangladesh's poultry industry suffered huge losses as bird flu caused over 1.98 million chickens' death since March 2007 in the country, the government's bird flu control room data showed.

The first bird flu in human body in Bangladesh was detected on May 21, 2008. The Center for Disease Control and Prevention in the United States, diagnosed a 16-month-old Bangladesh child as being infected with H5N1 who later recovered.