Is the swine flu outbreak related to the industrial food system?

Let's get one thing straight: swine flu is caused by a virus -- NOT by eating pork or pork products.  Here's a useful FAQ from the CDC.

But this article from Grist (and plenty of others) poses interesting questions about how swine flu could be linked to a major pork producer with hog farms in Mexico.  Here's the gist: hog waste attracts flies, and an early investigation suggested that a swine flu virus vector was a particular fly that reproduces in hog waste.

This article from the UK Guardian also provides a good timeline of events and possible links to hog farming.

Is it true?  

This quote from a biosurveillance professional puts things in perspective: "[we] simply flagged an event as worthy of closer scrutiny and higher awareness, as there was absolutely no proof of true involvement of this company in the outbreak- a proper epidemiological investigation is required to prove such links."  

The pork producer has an official statement here.

Writer David Lawrence warns about why we shouldn't jump to conclusions.  He writes: "A researcher has to reject all alternative hypotheses before being able to accept, or at least get other researchers to accept, his or her preferred hypothesis. Journalists covering scientific and medical matters should keep this fact in mind."

More food for thought: 

According to the CDC, "no formal national surveillance system exists to determine what viruses are prevalent in the U.S. swine population. Recent collaboration between the U.S. Department of Agriculture and CDC has led to development of a pilot swine influenza virus surveillance program to better understand the epidemiology and ecology of swine influenza virus infections in swine and humans."

Are CAFOs a problem for human health?

CAFOs are Confined Animal Feeding Operations.

The CDC says that possible pollutants from CAFOs include viruses, among other things, and "[we] do not yet know whether or how these or other substances from CAFOs may affect human health."

But research suggests otherwise. 

*"The North American swine flu virus has jumped onto an evolutionary fast track, churning out variants every year. Changes in animal husbandry, including increased vaccination, may be spurring this evolutionary surge. And if one of this slew of swine strains gains the ability to spread among people--as has apparently happened at least twice before--the consequences could be deadly." Source: Bernice Wuethrich, "Chasing the Fickle Swine Flu", Science, Vol. 299, 2003

*"Because CAFOs tend to concentrate large numbers of animals close together, they facilitate rapid transmission and mixing of viruses." Source: "The Potential Role of CAFOs in Infectious Disease Epidemics and Antibiotic Resistance," Journal of Environmental Health Perspectives, 14 November 2006

*The United Nations Food and Agriculture Organization states that the "concentration of livestock production in circumscribed areas generates significant animal and public health risks." Source: FAO Industrial Livestock Production and Global Health Risks