Friday, May 1, 2009
When I was a boy, my school sent my class on a field trip to a chicken processing plant.
I was astonished at the blood and guts, as chickens were conveyed on an assembly line to be zapped, beheaded, de-feathered, cleaned, and then packaged for sale.
The facility was highly sanitary, all gleaming stainless steel surfaces, with efficient catch-basins to instantly whisk the blood away.
While the plant was clean, the facility where the chickens were raised wasn't. However, that was before the meat industry started using giant "confined animal feeding operations" (CAFOs ), like the one in Mexico which may have spawned the swine flu outbreak.
CAFOs are not only inhumane - animals are usually packed in so tightly they can't even turn around, and the conditions are so unhealthy that the animals usually have to be pumped with huge amounts of medicines just to keep them alive - but they are also notorious incubators for diseases that can harm people.
As David Kirby - who is writing a new book on industrial animal production - writes this week:
Pigs are nature's notorious "mixing bowls" for inter-species infections, and many swine flu viruses have long contained human influenza genetic components...
For years, leading scientists around the world have worried that large-scale, indoor swine "factories" would become breeding grounds for new pathogens that could more easily infect humans and then spread out rapidly in the general population - threatening to become a global pandemic.
We know that hog workers in Europe and North America are far more likely than others to be infected with potentially lethal pathogens such as MRSA (Methicillin-resistant Staphylococcus aureus), drug-resistant E. coli and Salmonella, and of course, swine influenza. Many scientists also believe that people who work inside CAFOs are more at risk of contracting and spreading these and other "zoonotic" diseases than those working in smaller-scale operations, with outdoor pens or pasture and far lower animal density...
Last year, the Pew Commission on Industrial Farm Animal Production issued a lengthy report on factory farming that included research on emerging forms of avian-swine-human influenza viruses[:]The continual cycling of swine influenza viruses and other animal pathogens in large herds or flocks provides increased opportunity for the generation of novel viruses through mutation or recombinant events that could result in more efficient human-to-human transmission of these viruses. In addition, agricultural workers serve as a bridging population between their communities and the animals in large confinement facilities. This bridging increases the risk of novel virus generation in that human viruses may enter the herds or flocks and adapt to the animals.
Reassortant influenza viruses with human components have ravaged the modern swine industry. Such novel viruses not only put the workers and animals at risk of infections, but also potentially increase zoonotic disease transmission risk to the communities where the workers live. For instance, 64% of 63 persons exposed to humans infected with H7N7 avian influenza virus had serological evidence of H7N7 infection following the 2003 Netherlands avian influenza outbreak in poultry. Similarly, the spouses of swine workers who had no direct contact with pigs had increased odds of antibodies against swine influenza virus. Recent modeling work has shown that among communities where a large number of CAFO workers live, there is great potential for these workers to accelerate pandemic influenza virus transmission.
"We met with a team of researchers from the University of Iowa who are studying avian flu, and their real concern was the very scenario that may have happened in Mexico - that avian flu may get into a swine CAFO and rapidly mutate and then get passed to workers, and then on to other people very quickly," Bob Martin, who was executive director of the now-disbanded commission and currently a Senior Officer at the Pew Environmental Group, told me.
"Their concern was that new strains of avian flu combining with swine flu could make the swine flu more deadly," he said. "And because viruses pass so easily between pigs and people, the new avian component could make swine flu more virulent."
Researchers such as Gregory Gray, MD, a University of Iowa professor of international epidemiology and expert in zoonotic infections, warned that CAFO workers could serve as a "bridging population" to rural communities sharing viruses with the pigs, and vice-versa. Other scientists suggested that CAFO workers could theoretically spread disease quickly to great distances. An outbreak of infectious avian flu on the Eastern Shore of Maryland, for example, could reach the Rocky Mountains within 36 hours.
The Iowa team was also worried that CAFO production could lead to another 1918-style global pandemic. One theory behind that calamity is that waterfowl cross-infected U.S. pigs with a new type of avian-swine super-virus that was quickly transmitted to farm workers, possibly in Iowa, who went off to military training camps for WWI, and then spread the pathogen worldwide
"One very big concern was that swine flu mixed with wild bird flu, or bird flu in a chicken CAFO, tended to be ripe for incubating new types of viral infections, especially since the animals are so densely packed together," Bob Martin said...