Genetic Assessment of Swine Influenza Virus Isolates for Novel Strain

A novel H1N1 influenza virus (referred to as 2009 pandemic H1N1) emerged and caused clinical disease in the United States and other countries. Although human-to-human transmission was the main mode after initial outbreak, the potential and perception that pigs might have been the initial source of the novel strain had detrimental impact on both domestic and export markets of U.S. pigs and pork products. Although preliminary tests indicated otherwise, uncertainty existed as to whether or not the novel strain had been circulating undetected in the U.S. swine population. The evidence from this study found that evidence is lacking to show the novel H1N1 virus was circulating undetected in the United States prior to its emergence in humans. Cross-species transmission of the novel H1N1 strain from affected humans to animals including pigs was apparent, suggesting that good biosecurity measures and farm personnel management should be practiced when an influenza epidemic occurs in humans.

Source: NPB Research Review Newsletter