Avian influenza was found in a dog on a farm in South Gyeongsang Province amid growing concerns that the disease could spread to other animals, officials said Monday.

The dog ― one of three at a duck farm in Goseong-gun, South Gyeongsang Province ― had antigens for the highly pathogenic H5N8 strain of bird flu, the Ministry of Agriculture, Food and Rural Affairs said. The farm was affected by the disease on Jan. 23.

This is the first time bird flu has been found in a dog in Korea through the detection of antigens, but antibodies for the virus were found in a dozen dogs at virus-affected farms in March last year. The detection of antibodies suggests an immune response to the virus, the ministry said.

“None of these dogs had shown symptoms. No antigens or antibodies for the virus were found in the two other dogs, which means that dog-to-dog transmission is unlikely to have happened,” quarantine officials said.

The ministry suspected that the dog may have eaten infected animals at the farm.

All poultry and dogs at the concerned farm were slaughtered as part of the preventive measures right after the farm was reported to have been infected with the disease, officials said.

Meanwhile, quarantine officials rejected the possibility of viral transmission to humans.

According to the ministry’s report, about 450 workers at infected farms across the country had been given an antigen test, with none showing signs of infection. None of Korea’s 20,000 farm workers have reported any symptoms so far, officials added.

“It is thought that infected dogs do not show symptoms of the disease as they are naturally resistant to bird flu,” the ministry said.

Meanwhile, the Agriculture Ministry has toughened the quarantine measures in Goseong-gun. The region is a frequented by migratory birds, which are suspected to have spread the viral disease.

As of Monday, more than 1.8 million poultry had been slaughtered since the first outbreak in September last year in South Jeolla Province.

By Lee Hyun-jeong (rene@heraldcorp.com)