The ongoing outbreak of Swine Flu / novel influenza A (H1N1) highlights one of the many serious public health risks that industrial food animal production (IFAP) poses on a global scale. It is known that pigs are “mixing vessels” for influenza viruses (for swine, avian and human flu), and it is believed that the last two flu pandemics, in 1957 and 1968, broke out when avian flu and human flu viruses mixed genetically with pig viruses to create a new flu virus that was transferred back to people. It has also been suggested that the 1918 Spanish Flu originated from pigs (Chasing the Fickle Swine Flu, March 7, 2003, Science).

Insufficient evidence is available to definitively determine whether the current swine flu outbreak originated from IFAP swine operations. However, through analyses of genome sequences generated by the Centers for Disease Control and Prevention (CDC) from current virus isolates, Columbia University researchers have proposed two swine-related genetic ancestors of the current virus. Of these, one that accounts for six of the eight genetic segments of the virus has been identified as the H3N2 virus, a triple reassortment of swine, avian and human virus first isolated in pigs on a North Carolina swine operation in August of 1998. (Evolution of Swine H3N2 Influenza Viruses in the United States, Journal of Virology, September 2000) The other two segments are believed to be from swine viruses of Eurasian origin (Trifonov, 2009).

One feature of IFAP is the intensive confinement of large numbers of animals in facilities that serve as breeding grounds for new and potentially more infectious agents. In its report, “Putting Meat on the Table: Industrial Farm Animal Production in America,” the Pew Commission on Industrial Farm Animal Production warned that “the continual cycling of viruses and other animal pathogens in large herds or flocks increases the opportunities for the generation of novel viruses through mutation or recombinant events that could result in more efficient human-to-human transmission.” In light of the current swine flu outbreak and the favorable conditions found in IFAP swine operations for the development and transmission of novel viral strains, improved surveillance, not only for IFAP facilities, but also for facility workers, is needed to safeguard the health of the world’s population from future viral outbreaks and pandemics.

Some useful resources on swine flu outbreak
For the latest on the outbreak of Swine Flu novel influenza A (H1N1), please see this collection of links from Johns Hopkins Bloomberg School of Public Health. The Johns Hopkins Center for a Livable Future is also tracking news about the outbreak on the Livable Future Blog.