Workers at the emergency response headquarters for the avian influenza outbreak are busy tracking the spread of the bird flu, at the Gyeonggi Provincial Government in Suwon, south of Seoul, South Korea, on Feb. 11. Facing its worst avian influenza outbreak, South Korea has culled more than 33 million poultry since the first reported case last November. Photo by Yonhap/EPA
Feb. 22 (UPI) -- About 90,000 birds have been killed in South Korea as a precautionary measure against avian influenza, or bird flu.
The slaughter comes after local authorities determined they might have been exposed to a strain of bird flu spreading from migratory birds, Yonhap news agency reported.
About 100 chickens perished on one farm in central South Korea, in South Chungcheong Province. Fecal samples from three of the chickens tested positive for a strain of bird flu, provincial authorities said Wednesday.
In response to the findings, 90,000 birds being raised at the farm, and 1,108 chickens and ducks being raised within a 1.9-mile radius of the infected birds were slaughtered, according to the report.
A mobile control center has also been set up to monitor more than 1 million birds at 295 farms within a 6-mile radius of the infection.
South Korea's provincial authority says the source of the virus is migratory bird feces that could have spread across the region through water sources.
No cases of the virus have been reported at farms for 40 days, and it is unlikely there was a transmission by feed systems at the farms, according to the report.
South Korea has destroyed more than 33 million birds since November because of one of the worst avian flu outbreaks in its history, according to Yonhap.
In January, the country tackled a shortage of shell eggs by shipping in more than 1 million eggs from the United States.