Authorities have confirmed that a dog at a farm in Korea's Chungcheongnam-do province has been infected with the H5N8 strain of avian influenza.Korea's agriculture ministry said Friday that the dog had tested positive for having antibodies against the H5 strain, meaning its immune system is battling the virus.It's the first time in Korea that a mammal has come down with the AI virus.Authorities say the dog became infected after eating an infected chicken at the farm.Prior to this case, it was believed that the AI virus could only be transmitted among the same species."More studies need to be conducted on the possible affects of the H5N8 strain virus on mammals. There is no explanation yet as to why the dog was infected."It's raising concerns that humans could be susceptible to the H5N8 strain, but health authorities say that's very unlikely, although the farm's workers are being tested.Avian influenza cannot be transmitted through the air.All the poultry at the farm have already been culled.A fresh strain of the avian influenza virus broke out in mid-January at a duck farm in Jeollanam-do Province, and more than 70 cases of the virus have been confirmed since.Ji Myung-kil, Arirang News.