by Michael Greger, M.D., 28 Feb 2007

• Free-range and/or backyard chicken flocks are mainly to blame for the emergence and spread of  deadly bird flu viruses. 
  All bird flu viruses start out harmless to both birds and people. However, if they find their way into a filthy, football field-sized animal production shed crammed with tens of thousands of chickens, some strains can mutate into highly pathogenic forms.^[1]  The United Nations has publicly called on governments to fight what they call “factory farming”—industrialized animal agribusiness facilities, also known as Confined Animal Feeding Operations or CAFOs—which, combined with live bird markets, provide the “ideal conditions for the virus to spread and mutate into a more dangerous form.” ^[2]
  
  
• Birds in modern chicken factories are fully protected by “biosecurity.”
  Industry authorities admit high biosecurity is still “wishful thinking” in many areas of intensive poultry production. ^[3] A Virginia outbreak of bird flu in 2002 led to the deaths of millions of birds and found its way into 200 chicken sheds, highlighting just how wishful the thinking is that birds are protected inside industrial facilities.^[4] According to a leading poultry virologist with the U.S. Department of Agriculture (USDA), “[T]hat level of biosecurity does not exist in U.S. poultry production and I doubt that it exists in other parts of the world.” ^[5]
  
  
• Wild birds are the main vectors for spreading the virus.
  Although wild birds play some role in the spread of bird flu, the consensus reached at the International Scientific Conference on Avian Influenza and Wild Birds, jointly sponsored by the United Nations’ Food and Agriculture Organization (FAO) and the World Organization for Animal Health (OIE), was that the international trade in commercial poultry was the main means by which the virus has spread around the world. ^[6]
  
  
• Bird flu is only an Asian problem.
  Before the emergence of H5N1, the biggest outbreak of bird flu in history was not in China—it was in Pennsylvania. In the 1980s, the United States suffered the most costly and extensive disease eradication in its history, an outbreak of H5N2 that led to the deaths of 17 million chickens at a cost to taxpayers and consumers exceeding $400 million. ^[7] There have also been clinical cases of human infection with bird flu viruses in Virginia, New York, and Canada. ^[8]
  
  
• Infected chicken that is cooked properly poses no risk.
  Each year, 76 million Americans come down with food poisoning caused by bugs that are likewise killed by proper cooking. ^[9] Poultry products are not often brought into the home precooked, though, so infected fresh or frozen raw poultry may infect members of the household though cross-contamination of kitchen surfaces, utensils, or even hands. ^[10]
  
  
• If H5N1 could spark a pandemic, it would have happened by now.
  Though the Asian strain of H5N1 emerged nearly ten years ago in 1997, evidence suggests that the 1918 flu virus—which triggered the greatest medical disaster in history—was “smouldering” for at least 11 years before it went pandemic. ^[11] We simply don’t know enough about the ecology of these viruses to accurately estimate a timeline. H3N8, for example, circulated in horses in North America for nearly 40 years before jumping into dog populations and triggering the canine flu that grabbed headlines last fall.^[12] With regard to H5N1, a World Health Organization (WHO) and USDA research team has concluded that “[i]t is probably dangerous to rely on the ‘if it were going to happen it already would have’ argument’” ^[13]
  
  
• This is another Chicken Little story like the “swine flu debacle” of 1976.
  The critical difference is the current global scientific consensus that H5N1 may represent a genuine pandemic threat. Three decades ago in 1976, authorities throughout the world—including the World Health Organization—disagreed with the United States that the death of a single soldier from a swine influenza virus warranted universal vaccination. They thought America was overreacting. ^[14] With the H5N1 avian influenza virus, however, the world’s authorities are in agreement. As summarized by Lee Jong-wook, the late Director-General of the World Health Organization, H5N1 is a “grave danger for all people in all countries.” ^[15]
  
  
• With modern medicine, pandemics are less of a threat than in the past.
  Although modern medicine has made far-reaching and significant strides in the last several decades, these advances do not protect us from pandemics. For example, in terms of pharmaceuticals, production of a vaccine matched to the pandemic strain is expected to take six to eights months after a pandemic strikes. ^[16] And, of the two classes of anti-flu treatment drugs, one was rendered useless by farmers spiking their chickens’s water supply with the drugs, ^[17] and there is only enough supply of the remaining treatment for 2 percent of the American public. ^[18] Both venitilators ^[19] and hospital beds ^[20] are also in short supply. Given the population explosion, speed and volume of global air travel, and current human lethality of H5N1, the next pandemic may in fact be worse than 1918, which claimed 50 to 100 million lives.
  
  
• Young people with healthy immune systems need not be concerned.
  Unlike seasonal influenza, which tends only to kill the elderly and infirm, pandemic influenza can strike those in the prime of life. During the pandemic of 1918, mortality peaked in the 20- to 34-year-old age group. ^[21] Likewise, the average (median) age of those currently dying from H5N1 is 20 years old. ^[22] In both cases, the viruses seem to trigger a phenomenon known as a “cytokine storm,” in which the virus turns the victim’s immune system against itself, triggering a massive inflammatory overreaction in the lungs, which leads the victims to drown in their own bloody secretions. ^[23]
  
  
• The last two pandemics were mild; why expect the next to be any different?
  While around half of America’s youth fell ill during the flu pandemics of 1957 ^[24] and 1968, ^[25] each pandemic only killed about a million people worldwide. ^[26] This may relate to the fact that they both were triggered by half-and-half bird/human hybrid viruses to which the world’s population may have had some partial immunity. H5N1, like the virus of 1918, is wholly bird-like, ^[27] and, as such, according to the World Health Organization, the global human population may be especially vulnerable. ^[28]
  
  
• Nothing can be done to prevent future pandemics.
  The number of outbreaks of highly pathogenic bird flu viruses—H5N1 and others—in the first few years of this century already exceeds the total number recorded for the entire 20^th century. ^{[29] , [30] , [31] , [32]} As one leading flu scientist quipped, “We’ve gone from a few snowflakes to an avalanche.” ^[33] The United Nations’ Food and Agriculture Organization blames this recent, rapid emergence of increasingly dangerous flu viruses on the industrialization of the poultry sector. ^[34] By following the U.N.’s advice to “combat” the role of factory farming, we may reduce the likelihood of the emergence of at least hypervirulent strains like H5N1. If humanity stopped repopulating broiler chicken sheds that can hold tens of thousands of birds in each individual warehouse-like building, within weeks there would be billions fewer opportunities within which viruses like H5N1 could mutate.
  
  
• We’ve always had flu pandemics and we always will.
  Our current understanding is that human beings didn’t start getting the flu until they started domesticating birds like ducks. Natives of the Western hemisphere were likely not exposed to any of the killer scourages humanity acquired through the domestication of farm animals—such as tuberculosis, smallpox, and measles—until Europeans landed and brought these diseases with them. ^[35] Based on evidence from human influenza B and C viruses, if the domestication of birds for food ended, the pandemic cycle might be broken.
  
  
• There is nothing individuals can to do prepare.
  On the contrary, the Centers for Disease Control and Prevention and the U.S. Department of Health and Human Services have set up an excellent pandemic preparedness website, pandemicflu.gov, which details what businesses, communities, families, and individuals can do now to prepare for the next pandemic.