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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<http://www.fao.org/ag/AGAinfo/projects/en/pplpi/docarc/rep-hpai_indus...>."
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:
"It is curious, therefore, that changing the way humans treat animals—most
basically, ceasing to eat them or, at the very least, radically limiting the
quantity of them that are eaten—is largely off the radar as a significant
preventive measure. Such a change, if sufficiently adopted or imposed, could
still reduce the chances of the much-feared influenza epidemic. It would be
even more likely to prevent unknown future diseases that, in the absence of
this change, may result from farming animals intensively and from killing
them for food. Yet humanity does not consider this option. Insofar as the
focus is not on cures for the resultant diseases, attention is only given to
lesser preventive measures."
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<http://jama.ama-assn.org/cgi/content/full/298/16/1945>in this
week's issue of
*JAMA*, the most widely-circulated medical journal in the world:
*[image: JAMA: The Journal Of the American Medical Association. To Promote
the Science and Art of Medicine and the Betterment of the Public
Health]<http://jama.ama-assn.org/>
*
*Vol. 298 No. 16, October 24/31, 2007***
*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
xavbo...@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
