US confirms H5N1 bird flu in swine for first time
The Avian influenza H5N1 virus has been detected in at least one pig at a backyard farm in Oregon (Crook County), marking the first identification of the H5N1 virus in swine in the United States. The genotype is D1.2. different that the B3.13 genotype circulating in US dairy cattle. This discovery raises significant concerns among scientists and public health officials, as pigs are classified as "mixing vessels." They can become co-infected with both avian and human viruses, which facilitates genetic reassortment and the potential emergence of a new, more virulent strain that could more easily infect humans.
Bird flu was initially detected in poultry on this noncommercial farm. In response, state and federal agricultural authorities euthanized 70 infected backyard birds last week to prevent further spread of the virus. One of the farm's five pigs tested positive for the virus; however, it did not exhibit any signs of illness. While the infected swine were euthanized, other animals on the farm, including sheep and goats, remain under surveillance.
In 2004, a researcher from China's Harbin Veterinary Research Institute presented initial evidence indicating that pigs from farms in certain regions of China have been infected with the H5N1 strain of avian influenza. These findings were presented today at an international symposium on SARS and avian influenza held in Beijing.
