Division 1 AI in pigs

AI viruses readily infect pigs and although replication is in most cases relatively restricted, there is a potential that infected pigs could transmit the disease to poultry and other susceptible animals. To date, there is no evidence from the field that infected pigs transmit AI viruses of H5 and H7 subtypes.

Experience gained during the outbreak in the Netherlands in 2003 indicated that H7N7 infected pigs did not show clinical signs that could be attributed to the H7N7-infection. Moreover, apparently no diseased pigs have been reported to date during the H5N1 outbreak in Asia and elsewhere.

Therefore, clinical signs may not be relied upon to indicate whether pigs are infected although clinical presentation due to infection of pigs with other influenza viruses of avian origin, can occur once a virus has become adapted to the host. The diagnosis of AI virus infections of pigs is essentially similar to diagnosis for avian species, relying on virus isolation, molecular techniques and detection of specific antibodies using haemagglutination inhibition tests. There are, however, certain differences and none of the tests are fully validated for the use in pigs to confirm infection with AI viruses.