January 8, 2010
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I was intrigued (and disturbed) by a book I just read online -- www.BirdFluBook.org -- by Michael Greger, M.D. about the potential of a deadly flu pandemic, the likes of which we have never seen. Greger very clearly delineates how a virus begins, mutates, and becomes dangerous. As with so many problems we are seeing lately -- environmental or health -- factory farmed meat seems to be a big part of the cause. A graduate of the Cornell University School of Agriculture and the Tufts University School of Medicine, Michael Greger, M.D., serves as Director of Public Health and Animal Agriculture at The Humane Society of the United States. An internationally recognized lecturer, he has presented at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, and was an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial. His recent scientific publications in American Journal of Preventive Medicine, Biosecurity and Bioterrorism, Critical Reviews in Microbiology, and the International Journal of Food Safety, Nutrition, and Public Health explore the public health implications of industrialized animal agriculture.
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.
KF: How does a virus like that kill? What does it do to the body?
MG: Most often it starts with standard flu-like symptoms--fever, cough, and muscle aches. Instead of just infecting the respiratory tract, though, H5N1 may spread throughout the body and infect the brain, for example, leaving victims in a coma. Other early symptoms atypical of regular seasonal flu include vomiting, diarrhea, abdominal pain, chest pain, and bleeding from the nose and gums. Death is usually from acute fulminant respiratory distress, in which one basically drowns in one's own blood-tinted respiratory secretions.