(...) Kathy Freston: How likely are we to have a bird or swine flu that turns into something really deadly and widespread?
Michael Greger: Unfortunately we don't know enough about the biology of these viruses to make accurate predictions, but influenza is definitely the disease to keep an eye on. AIDS has killed millions but is only fluid-borne. Malaria has killed millions but is relatively restricted to equatorial regions. Flu viruses are the only known pathogen capable of infecting literally billions of people in a matter of months. Right now we are in the midst of a flu pandemic caused by the swine-origin influenza virus H1N1. Millions of people have become infected and thousands have died, but H1N1 is not particularly virulent. There are other flu viruses that have emerged in recent decades such as the highly "pathogenic" (disease-causing) bird flu H5N1 that may have the potential to cause much greater human harm.
KF: What kind of damage could it do in terms of population mortality?
MG: Currently H5N1 kills approximately 60% of those it infects, so you don't even get a coin toss chance of survival. That's a mortality rate on par with some strains of Ebola. Thankfully, only a few hundred people have become infected. Should a virus like H5N1 trigger a pandemic, though, the results could be catastrophic. During a pandemic as many as 2 or 3 billion people can become infected. A 60% mortality rate is simply unimaginable. Unfortunately, it's not as far-fetched as it sounds. Both China and Indonesia have reported sporadic outbreaks of the H5N1 bird flu in pigs and sporadic outbreaks of the new pandemic virus H1N1 in pigs as well. Should a pig become co-infected with both strains, a hybrid mutant could theoretically arise with human transmissibility of swine flu and the human lethality of bird flu. That's the kind of nightmare scenario that keeps virologists up at night.
(...) Most of the damage is actually done by one's own immune system. H5N1 seems to trigger a "cytokine storm," an overexuberant immune reaction to the virus. These cytokine chemical messengers set off such a massive inflammatory reaction that on autopsy the lungs of victims may be virus-free, meaning that your body wins, but in burning down the village in order to save it you may not live through the process. (...)
KF: Why do we have this potential disaster on our hands?
MG: The industrialization of the chicken and pork industries is thought to have wrought these unprecedented changes in avian and swine influenza. No one even got sick from bird flu for eight decades before a new strain, H5N1, started killing children in 1997. Likewise, in pigs here in the U.S. swine flu was totally stable for 8 decades before a pig-bird-human hybrid mutant virus appeared in commercial pig populations in 1998. It was that strain that combined with a Eurasian swine flu virus ten years later to spawn the flu pandemic of 2009, sickening millions of young people around the world.
The first hybrid mutant swine flu virus discovered in the United States was at a factory farm in North Carolina in which thousands of pregnant sows were confined in "gestation crates," veal crate-like metal stalls barely larger than their bodies. These kind of stressful, filthy, overcrowded conditions can provide a breeding ground for the emergence and spread of new diseases. (...)
KF: How do we stave off this viral apocalypse?
MG: We need to give these animals more breathing room. The Pew Commission on Industrial Farm Animal Production, which included a former U.S. Secretary of Agriculture, concluded that industrialized animal agriculture posed "unacceptable" public health risks and called for gestation crates for pigs to be banned as they're already doing in Europe, noting that "practices that restrict natural motion, such as sow gestation crates, induce high levels of stress in the animals and threaten their health, which in turn may threaten human health."
Studies have shown that measures as simple as providing straw for pigs so they don't have the immune-crippling stress of living on bare concrete their whole lives can significantly cut down on swine flu transmission rates.
Rise of the Superbugs: Why We Are Increasingly at Risk From Antibiotic-Resistant Diseases
The evidence is overwhelming that these new superbugs are at least partially a result of dosing farm animals with subtherapeutic doses of antibiotics added to their feed.
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