*Dr. Greger's Pandemic Update: October 2007*
Speaking Tour
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Dr. Greger's Pandemic Update: October 2007
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CONTENTS
I. U.S. agribusiness responds to FAO report
II. American Journal of Public Health editorial offers radical solution
III. Highly pathogenic avian influenza outbreak in North America
IV. Journal of the American Medical Association reviews Bird Flu
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I. U.S. agribusiness responds to FAO report
In my last update, I noted that recent reports by the World Health Organization and the Food and Agriculture Organization (FAO) of the United Nations implicated the industrialization of animal agriculture in the escalating emergence of animal-to-human diseases with potentially tremendous public health implications like H5N1. (At the International Bird Flu Summit where I presented last month, risk analysis and global strategy firms Marsh and the Albright Group released their pandemic toll estimate of perhaps 140 million people dead at a cost exceeding $4 trillion.) I am often asked how the livestock industry responds to these kinds of official pronouncements of the public health risks associated with its enterprises.
Feedstuffs is the leading U.S. agribusiness trade weekly. In a recent issue, an op-ed was published in response to the FAO report, in association with scientists at Johns Hopkins, entitled "Industrial Livestock Production and Global Health Risks." The op-ed reads: "FAO claims to use scientists to generate its reports, but I wonder if those scientists don't resemble a bearded guy living in a cave in Pakistan who wants the U.S. on its knees."[1]
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II. American Journal of Public Health editorial offers radical solution
The public health community has a different response. The American Journal of Public Health is the official publication of the American Public Health Association (APHA)—the oldest, largest, and most diverse organization of public health professionals in the world. (I'm looking very much forward to presenting at their annual conference next week!). In its September 2007 issue, an op-ed was published that went beyond the recommendations to de-intensify poultry production that I mentioned in my last update and questions the necessity of eating so many chickens in the first place. Noting the level of human suffering caused by diseases that originated from animals such as AIDS, SARS, and mad cow disease, which "probably could have been avoided had humans treated animals better," the editorial states:
Dr. Benatar's American Journal of Public Health editorial concludes:
"Humans have suffered a great deal as a result of the mistreatment of animals…In any event, those humans who suffer are not just the ones responsible for animal mistreatment. Innocents are often adversely affected. When the (infected) chickens come home to roost, it may be another person, possibly from the next generation, who suffers or dies from avian influenza. Those who consume animals not only harm those animals and endanger themselves, but they also threaten the well-being of other humans who currently or will later inhabit the planet. To switch avian images, it is time for humans to remove their heads from the sand and recognize the risk to themselves that can arise from their maltreatment of other species."[2]
The entire editorial can be read here: http://birdflubook.com/resources/ajph1545.pdf
In 2003, the APHA passed a "Precautionary Moratorium on New Concentrated Animal Feed Operations" in which it urged all U.S. federal, state, and local authorities to impose an immediate moratorium on the building of new large-scale industrial livestock facilities out of concern for the health of local communities given the associated land, air, and water pollution. The prudence of such a proposal grows with our increasing understanding of the dangers potentially posed by these operations to the global population in terms of the emergence of new human infectious diseases.
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III. Highly pathogenic avian influenza outbreak in North America
Last month's emergence of a highly pathogenic H7N3 virus in a Canadian poultry facility reportedly confining more than 50,000 chickens once again underscores the threat these operations may pose. The Chicken Farmers of Canada assured the public that the strain poses no danger to human health,[3] but highly pathogenic H7 viruses have shown the capacity to cause serious human infections, killing a veterinarian in the Netherlands in 2003[4] and hospitalizing three people in Wales earlier this year with respiratory illness, one who became so ill, the patient become a candidate for intensive care.[5]
Jonathan Nguyen-Van-Tam, a senior lecturer at Public Health Laboratory Services in London, presented the Welsh cases at a special late-breaker session at the major annual scientific influenza conference this summer. "I think we need to reconsider the H7 strain on the basis of this outbreak," he concluded.[5] Recalls one victim, "I thought was going to die."[6]
Although H5N1 has the highest documented human lethality of any flu virus in history, its human transmissibility is extremely limited. The highly pathogenic H7N7 virus in the Netherlands outbreak infected 33 of 56 (58.9%) household members of infected poultry workers with no known exposure to infected birds[7] with plausible second-generation human-to-human transmission.[8] This suggested an ease of intrafamilial avian influenza transmission on par with seasonal flu.[9] Based on the seroprevalence of H7 antibodies, it was estimated that at least 1,000 and perhaps as many as 2,000 people were infected in the outbreak.[10] According to World Health Organization bird flu expert Michael Perdue, "There may be a bit of complacency when it comes to recognizing the pandemic potential of H7 viruses."[11]
In my Foreword (http://birdflubook.com/a.php?id=115), University of Hong Kong Professor Emeritus Dr. Kennedy Shortridge, credited with discovering H5N1 in Asia, compares the factory farming of chickens with the cannibalistic feeding practices that likely led to the emergence of mad cow disease. It is "profitable in the short term for animal agriculture," he wrote, "but with the potential for unforeseen and disastrous consequences. Intensified, industrial poultry production has given us inexpensive chicken, but at what cost to the animals and at what heightened risk to public health?"
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IV. Journal of the American Medical Association reviews Bird Flu
I am excited to report that my book Bird Flu was reviewed in this week's issue of JAMA, the most widely-circulated medical journal in the world:
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Vol. 298 No. 16, October 24/31, 2007 |
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Book and Media Reviews |
Bird Flu: A Virus of Our Own Hatching
By Michael Greger, 416 pp, $30.
New York, NY,
Lantern Books, 2006.
ISBN-13 978-1-5905-6089-1.
JAMA. October 24-31, 2007;298:1945-1946.
Worries about a forthcoming influenza pandemic have a solid historical foundation. Although the timing remains uncertain, flu pandemics have a relapsing pattern and incur enormous human and economic costs. Of the three 20th-century influenza pandemics, that of 1918-1919 is considered the most deadly disease event in human history.
The US Centers for Disease Control and Prevention (CDC) estimates that in a normal flu season some 200,000 individuals in the United States are hospitalized and 38,000 die of influenza, mostly elderly persons, with annual direct medical costs and lost productivity calculated at $12 billion. However, these figures pale before the catastrophe implied by a severe influenza pandemic. The CDC predicts that a medium-level epidemic would affect a third of the US population, hospitalize 734,000, and kill almost 210,000. With failure to produce an effective vaccine and with a virus untouched by anti-influenza drugs, an epidemic of the H5N1 avian influenza via person-to-person transmission could wreak havoc. With a probable 80 million disease episodes, a 20% mortality rate would result in 16 million deaths. The human tragedy and economic upheaval would be unprecedented.
The first cases of human infection by the highly contagious H5N1 avian influenza virus in Hong Kong in 1997 reinvigorated influenza research. This is an aggressive disease in fowl, with domestic chickens and turkeys being most severely affected (mortality exceeds 50%).
In Asia, the economic importance of poultry and poultry products has increased dramatically over the last 10 years, becoming a staple food that provides approximately 30% of total dietary protein, especially in rural households. Yet in several affected countries, up to 80% of poultry production occurs in backyard holdings and small rural farms.
Although outbreaks in poultry affect economies and food security, the greatest concern is that present conditions could trigger an influenza pandemic. However, the small number of human cases to date (approximately 150) suggests that H5N1 is not currently easily transmitted from birds to humans. Two mechanisms could change this. Effective interhuman transmission could follow the exchange of gene segments (ie, reassortment) when humans or pigs are simultaneously infected with H5N1 and a currently circulating human influenza virus is adapted for efficient transmission. The second mechanism is mutation during human infection, with only a small number of mutational changes thought to be needed.
What has happened for this innocuous intestinal bug, which has affected wild ducks for millions of years, to become a killer? In Bird Flu: A Virus of Our Own Hatching, Michael Greger, MD, depicts the human role in the evolution of the virus into a lethal mutant strain.
Greger, Director of Public Health and Animal Agriculture at the Humane Society of the United States, discusses how human mistreatment of animals has actually backfired, with factory farming making livestock more susceptible to disease. He explains how modern livestock production facilitates the transmission and evolution of avian influenza and argues convincingly that the right environment for a virus such as H5N1 to thrive now exists.
The message is that pandemics are not born but rather are man-made—and that there is a price to pay for the modern poultry industry, in which fowl are raised in closed, stressful, unhealthy facilities, facilitating mutation and dissemination of the bird flu virus. Greger writes that "[It] may take a pandemic with a virus like H5N1 before the world realizes the true cost of cheap chicken."
The Foreword is by Kennedy Shortridge, PhD, credited with discovering the H5N1 virus in Asia. The book subsequently contains 5 logically organized sections: an introduction to the history and biology of influenza ("Storm Gathering"), a discussion of the socioeconomic factors responsible for the increased threat of animal viruses to humans ("When Animal Viruses Attack"), an explanation of the antipandemic measures instigated in response to the emergence of H5N1 ("Pandemic Preparedness"), an overview of the individual measures available to combat a pandemic ("Surviving the Pandemic"), and a section entitled "Preventing Future Pandemics."
Greger also discusses other animal pathogens that may become human threats and argues that the environment that caused the emergence of the H5N1 virus can also trigger these transformations.
There remains room for hope. As Greger states in the Introduction, "[if] changes in human behaviour can cause new plagues, changes in human behaviour may prevent them in the future." A radical change from factory farming to less intensive methods including free-range farming is needed, especially in the poultry industry, in which "humanity must shift toward raising poultry in smaller flocks, under less stressful, less crowded and more hygienic conditions, with outdoor access."
Greger paints the science behind the bird flu virus, explaining recent theories on the evolution, pathogenesis, mutation, and spread of the virus. He discusses polemic issues such as the household storage of influenza antiviral agents and class differences in access to potentially scarce supplies of antivirals during a pandemic.
The book is timely, well-researched, and particularly incisive on farming methods worldwide, especially those for poultry. Although the repetition of the unavoidable horrors to come and our responsibility for them is sometimes wearying, this is a valuable resource for scientists and the public alike.
Financial Disclosures: None reported.
Xavier Bosch, MD, PhD, Reviewer
Department of Internal Medicine
University of Barcelona
Barcelona, Spain
xavb...@clinic.ub.es
Book and Media Reviews Section Editor: John L. Zeller, MD, PhD, Contributing Editor.
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REFERENCES
[1] Loos T. 2007. Here's something to crow about. Feedstuffs. September 24:8.
[2] Benatar D. 2007. The chickens come home to roost. Am. J. Public Health 97(9):1545-6.
[3] 2007. 2nd Saskatchewan farm under quarantine over avian flu worries. CBC News, September 29. http://www.cbc.ca/canada/saskatchewan/story/2007/09/29/avian-flu.html
[4] Fouchier, R.A., et al. 2004. Avian influenza A virus (H7N7) associated with human conjunctivitis and a fatal case of acute respiratory distress syndrome. Proc. Natl. Acad. Sci. USA
10 1, 1356–1361.
[5] Susman E. 2007. Analysis: Bird flu fears reignited. United Press International, June 19.
[6] Traynor L. 2007. We thought we would die from bird flu. Liverpool Echo, May 31.
[7] Du Ry van Beest Holle, et al. 2005. Human-to-human transmission of avian influenza A/H7N7, The Netherlands, 2003. Euro. Surveill. 10, 264–268.
[8] van Boven, M., et al. 2007. Detecting emerging transmissibility of avian influenza virus in human households. PLoS Comput. Biol. 3, e145.
[9] Jennings, L.C., and Miles, J.A. 1978. A study of acute respiratory disease in the community of Port Chalmers. II. Influenza A/Port Chalmers/1/73: Intrafamilial spread and the effect of antibodies to the surface antigens. J. Hyg. (Lond.) 81, 67–75.
[10] Bosman, A., Meijer, A., and Koopmans, M. 2005. Final analysis of Netherlands avian influenza outbreaks reveals much higher levels of transmission to humans than previously thought. Euro. Surveill. 10, E050106.2.
[11] Associated Press. 2007. Mild bird flu in Britain has pandemic potential, experts say. International Herald Tribune, May 29.
Michael Greger, M.D.
Director, Public Health and Animal Agriculture
The Humane Society of the United
States
2100 L St., N.W.
Washington, DC 20037
direct line: (202) 676-2361
fax: (202) 676-2372
http://www.birdflubook.org