Swine Influenza Virus (SIV) is regarded as one of the major respiratory viruses of pigs. The clinical disease of "swine flu" can be caused by a number of different strains, which can be detected with polymerase chain reaction (PCR) tests, a fast and accurate testing method that in this case analyzes nasal swabs and oral fluid from individual animals as well as pen-based samples.
The variable genetic makeup of the different strains is a result of the ability of the virus to combine elements from different strains into a new strain, by a process called reassortment. The reassortment activity is not limited to pig influenza strains, but also includes elements from avian and human strains. The resulting new virus strains can be antigenically quite different than their origin strains, and animals will not have a pre-existing immune response to them even if they have been infected with SIV before.
Therefore, any newly reassorted strain will have a significant negative impact on the efficiency and profitability of swine production. Even though the mortality in SIV infections is moderate, the morbidity is usually 100% with rapid onset of illness. Additionally, the presence of SIV can significantly increase the effects of other respiratory infectious diseases on the farm. Control by vaccination is difficult due to the ever changing structure and antigenic makeup of SIV strains.
Symptoms in pigs are similar to flu symptoms in humans. In very rare cases SIV can be zoonotic. General turnaround time is next day testing from receipt.