It looks like the center of the swineflu outbreak in Mexico may well end up being a filthy pig slaughter operation run by a subsidiary of the Virginia-based Smithfield Foods, so well known for its hams. The company denies there is anything wrong with its operations. But Tom Philpott of Grist Magazine has been writing about the connection, and his most recent article is well worth reading. He notes:
The disease emerged as early as February and infected 60 percent of the town’s 1,800 inhabitants, according to the widely cited blog Biosurveillance, run by the U.S. disease-tracking consultancy Veratract (which claims the CDC, the World Health Organization, and the Pan-American Health Organization as clients). Three children died during the outbreak, Veratract reports. Residents blamed the Granjas Carroll confinements for the outbreak; and local authorities evidently agreed. “Health workers soon intervened, sealing off the town and spraying chemicals to kill the flies [which grew in swarms on Granjas Caroll’s manure lagoons] that were reportedly swarming through people’s homes,” according to a Monday account in the Guardian.
Some commentators say flies on manure piles are not possible vectors for the flu, but Philpott writes that he “recently got my hands on a paper by an international team of scientists—including Jay Graham and Ellen Silbergeld of Johns Hopkins—published in the May-June 2008 Public Health Reports. The paper, “The Animal-Human Interface and Infectious Disease in Industrial Food Animal Production: Rethinking Biosecurity and Biocontainment,” points to a concrete example of flies acting as a flu vector” [at a Japanese poultry farm in 2004]. Philpott continues:
The public-health scientific community has been sounding the alarm for years about the potential for bio-catastrophe brewing on industrial animal farms. The Graham/Sibergeld paper crystallizes those concerns. I’ll tease out a few key themes.
Untreated manure in lagoons, pointed to by La Gloria residents as a health hazard, can indeed contain flu strains….
Regulatory regimes, in the U.S. and elsewhere, tend to be lax. Sanitary laws demand the treatment of human sewage; animal waste is a different story….
The amount of untreated waste allowed to fester in CAFOs [concentrated animal feeding operations–i.e. factory farms] globally is stunning….
And of course, this vast amount of manure is highly concentrated geographically. For example, the bulk of pork consumed in the United States comes from a handful of counties in Iowa and North Carolina. In Mexico, the Perote region of Vera Cruz carries the burden of intensive hog production. The relatively few workers who staff these industrial farms, as well as the residents who live nearby, are vulnerable to the pathogens—and can carry them to far-flung populations.
The paper’s authors note the significance of their findings to the avian flu threat–but it all applies equally well to our current swine flu crisis.
Understanding interactions between animals and humans is critical in preventing outbreaks of zoonotic disease. This is particularly important for avian influenza. Food animal production has been transformed since the 1918 influenza pandemic. Poultry and swine production have changed from small-scale methods to industrial-scale operations. There is substantial evidence of pathogen movement between and among these industrial facilities, release to the external environment, and exposure to farm workers, which challenges the assumption that modern poultry production is more biosecure and biocontained as compared with backyard or small holder operations in preventing introduction and release of pathogens….Data suggest that successful strategies to prevent or mitigate the emergence of pandemic avian influenza must consider risk factors specific to modern industrialized food animal production.