Monday, December 24, 2012
China - Pigs In China’s Guangdong Province Infected With Avian Flu
Scientists have made a startling discovery that pigs in China’s Guangdong province are infected with avian influenza viruses.
Scientists have made a startling discovery that pigs in China’s Guangdong province are infected with three strains of avian influenza viruses.
Led by Dr. Zhang Guihong, a team of scientists from the College of Veterinary Medicine, South China Agricultural University in Guangzhou published their findings recently in the Journal of Clinical Microbiology.
In the period from 2010 to 2012, the scientists examined serum from pigs for both the avian and swine types of influenza virus. In total, 1,080 21- to 25-week-old pigs were tested for the H3, H4, H5, and H6 subtypes of avian influenza virus, and the H1 and H3 subtypes of swine influenza virus.
Looking first at the avian influenza A virus, 0.93 percent of pigs were positive for the H3 subtype, 1.6 percent were positive for the H4 subtype, and 1.8 percent were positive for the H6 subtype.
Of the swine flu virus, 35 percent of pigs were positive for H1N1, and 19.7 percent were positive for H3N2.
None of samples were positive for the avian H5 virus, which meant that the pigs had most likely been sporadically infected with the H3, H4, and H6 subtypes.
Importantly, no serum samples collected in 2001 were positive for any of the avian viruses, indicating that transmission into swine was recent.
Influenza A virus is responsible both for pandemics that have killed millions worldwide, and for the much less severe annual outbreaks of influenza. Because pigs can be infected with both human and avian influenza viruses, they are thought to serve as “mixing vessels” for genetic reassortment that could lead to pandemics.
In the lab, pigs have been infected experimentally by all avian H1-H13 subtypes. However, natural transmission of avian influenza to pigs has been documented only rarely.
“We recommend strongly that the pork industry worldwide should monitor the prevalence of influenza in pigs, considering their important role in transmitting this virus to humans,” said Dr. Zhang.
The article can be found at: Su S et al. (2012) Seroepidemiological evidence of avian influenza A virus transmission in pigs in southern China.