Another case of avian influenza was found in a dead bird in the southeastern city of Gyeongsan, quarantine officials said Thursday, as they struggled to contain the virus that has ravaged poultry farms across the country since mid-November.

According to the Veterinary Service Laboratory affiliated with the government of North Gyeongsang Province, the highly pathogenic

H5N6 strain of the bird flu was discovered in the dead body of a swan found on Sunday in the city some 331 kilometers southeast of Seoul.

Immediately after the finding, the quarantine authorities restricted the movement of poultry being raised within 10 km of the location where the swan was found, officials said.

Still, the authorities assume AI might not yet have spread to the region, which had been considered safe from the virus, given that swans are migratory birds that are not raised in the province.

The first outbreak of bird flu in nearly seven months was reported at a chicken farm in Haenam, about 420 kilometers south of Seoul, on Nov. 16.

It was caused by the highly pathogenic H5N6 strain of bird flu, a new type of virus that was first detected in South Korea. (Yonhap)