New Analysis of H1N1 and Swine: Separating Fact From Fear

Last spring when “swine flu,” now referred to as the H1N1 virus outbreak first occurred, internet journalists suggested that one or more Mexican swine CAFO’s (Concentrated Animal Feeding Operations) may have been the source. See Tom Philpott’s posts on Grist and David Kirby’s on Huffington Post. Smithfield, the owner of the CAFOs strongly denied the allegations, citing their own internal testing. Due to the rapid replication of viral strains, there is no way to find out where the outbreak actually originated.

Questions swirled about why it was called “swine flu,” pork sales plummeted, and the pork industry went on a massive public relations campaign. There was never any link between eating pork and getting the flu - H1N1 is a respiratory virus. The connection to pigs, however, goes all the way back to the flu pandemic of 1918. It is not known whether humans first infected pigs or pigs infected humans, but as pigs can survive infection, they have been "a reservoir for the virus ever since."

A new article, Swine CAFOs and Novel H1N1 Flu: Separating Facts from Fears, by Charles W. Schmidt, just published in Environmental Health Perspectives Volume 117, Number 9, September 2009 addresses these issues and provides a thoughtful, point by point discussion.

While some rumors are dispelled, other fears are reaffirmed. The article notes that public health scientists continue to express concerns about whether enough effort is being made to study the role of CAFOs and the animal-to-human transmission that occurs through the farm workers in such a concentrated environment. The article discusses these concerns, including the lack of research and testing about human viruses in swine CAFOs, despite our knowledge of the easy transmission between the two species. Research from Iowa in 2007 “strongly suggests that CAFO workers and veterinarians can infect other people with H1N1 viruses,” showing that “CAFO workers were 50 times more likely to have elevated H1N1 antibodies than nonexposed controls.” Their spouses were “25 times more likely to harbor these antibodies.” Nevertheless, we do not have required reporting or a coordinated, effective government effort in this area. Testing now is almost exclusively in the hands of those in the pork industry, with great disincentives for reporting human health problems; research is largely funded by the same industry; OSHA workplace standards exempt most CAFO workers; and workers are widely dispersed, with no regional or national network.

I recommend the article to anyone interested in either public health or the pork industry.