Abstract: Pigs serve as major reservoirs of H1N1 and H3N2 influenza viruses which are endemic in pig populations world-wide and are responsible for one of the most prevalent respiratory diseases in pigs. Furthermore, swine H9N2 influenza viruses might be a potential threat to human health and continuing to carry out swine influenza virus surveillance in China is of great significance. From March 2010-2011, researchers carried out serological surveillance of swine influenza in seven cities located Guangdong province in South China. The serological results indicated that antibodies to H1N1 swine influenza virus in the swine population were high with a 34.6% (226/653) positive rate whereas antibodies to H3N2 swine influenza virus were low with a 16.4% (107/653) positive rate. Antibodies to H9N2 swine influenza virus were very low with a 1.4% (9/653) positive rate. H1N1 influenza viruses were more dominant in the pig population than H3N2 influenza viruses in South China. H9N2 influenza virus in the pigs only send out the phenomenon in South China. According to reports in the virology and molecular epidemiological studies, the South China coastal areas of the global influenza research in key areas is the region of finding new influenza subtypes in the world and influenza outbreak. Therefore, the presence of H9N2, H1N1 and H3N2 subtypes in pigs of China and the potential public health significance have become the focus of attention of the global influenza research. After the outbreak of the flu pandemic in 2009, researchers had done a serological survey of large-scale farms in seven cities in Guangdong province. The results showed that swine influenza virus infections are more common in the surveyed farms: all farms were infected by swine influenza virus infection and more than half of the pigs present antibody-positive.
Fei-Xia Gu, Wen-Bao Qi, Shuo Su, Ji-Dang Chen, Hai-Tao Qi, Wan-Jun Zhu, Zhen Huang, Li-Kai Tan and Gui-Hong Zhang, 2012. Serological Surveillance of Swine Influenza Virus Infection in Seven Cities Located in Guangdong Province, South China in 2010. Journal of Animal and Veterinary Advances, 11: 3068-3072.