Dear Pablo: I have been following the media field day on the outbreak of swine flu but I can't help but wonder if factory farms are to blame for swine flu?
What Is Swine Flu?
First of all let me clarify that Swine Flu, or Swine Influenza Virus (SIV), is a strain of influenza that is endemic to pigs. You may recall the talk about the H5N1 strain last year, which refers to a human version of avian influenza. Luckily the H5N1 strain has, so far, not been transmissible from human to human, but H1N1 (swine flu) has. In a few past cases, such as in Wisconsin in 1988, swine flu was contracted by humans working in the swine industry, but the virus' ability to spread from human to human was limited and the outbreak quickly disappeared. An outbreak in 1976 resulted in one third of the US population getting vaccinated against swine flu, but the vaccine ended up killing more people than the swine flu itself. However, back in 1918, the "Spanish Flu" believed to be a strain of swine influenza swept around the world, infecting one third of the world's population and causing 50 million deaths.
The latest numbers on the US cases of H1N1 are available from the CDC. When compared to the CDC's estimate of annual influenza-related deaths of 36,000 in the US, it seems like the news media and public health systems are making a big deal out of nothing. But the current overabundance of caution is well justified considering that little is known about the current strain's mortality rate, infectiousness, resistance to medication, etc. The 2009 outbreak could fizzle away and be forgotten like Y2K or it could grow to "Spanish Flu" proportions.
But Are Factory Farms To Blame?
It is now widely believed, but not confirmed, that Édgar Hernández, a 5 year old Mexican boy from the village of La Gloria, is "Patient 0," or the first person to have contracted the current swine flue strain. Édgar has since fully recovered and has been visited by the global media, including CNN's Sanjay Gupta. While the villagers maintain that the source of the outbreak are the unsanitary conditions produced by a nearby factory hog farm, the farm's owners, Virgina-based Smithfield Foods maintains that none of its animals have tested positive for the strain. The allegations against Smithfield may turn out to be false, but may be based in legitimate health concerns by the villagers, 450 of whom say that they are suffering respiratory problems due to the farm.If the source of the current outbreak turns out to not be this particular factory farm, suspicion will undoubtedly fall on another factory farm. Bob Martin, senior officer at the Pew Environment Group and a member of the Pew Commission on Industrial Farm Animal Production believes that the current hog production system in the U.S. (and elsewhere) can act as a breeding ground for infections, including swine flu. The close proximity with which animals are held at these farms can encourage the spread of diseases such as swine flu. To counteract this, animals are given antibiotics, which make their way into our food, end up in factory effluent, and contribute to antibiotic resistant diseases. One article in the Daily Mail addresses this issue and talks specifically about the increase in drug resistant salmonella, campylobacter, MSRA (methicillin-resistant Staphylococcus aureus), and E. Coli. It is important to note that, unlike salmonella and E. coli, swine flu is not transmitted by eating pork and the USDA and CDC are emphasizing that eating pork is completely safe.Finally, agricultural workers, who serve as a "bridging population," can spread disease from the animals in their care and to the broader community. According to Dr. Anne Schuchat, interim Deputy Director for CDC Science and Public Health, American cases were found to be made up of "an unusually mongrelised mix of genetic sequences" from four different flu viruses – North American swine influenza, North American avian influenza, human influenza, and swine influenza virus typically found in Asia and Europe. So dense populations of pigs breed swine influenza, overuse of antibiotics breeds drug resistant strains, and close contact with humans creates hybridized strains of human and swine influenza genes that can be passed from swine to humans and between humans.Further information that became available at press time states that the current outbreak is related to a strain that was born on US hog farms in 1998.