Bird Flu Coming Home to Roost
The Satya Interview with Michael Greger
Photo courtesy of Michael Greger
The avian flu—the deadly H5N1 virus that has killed millions of
birds and at least 74 humans—has been a hot topic for discussion
recently. But there has been very little attention drawn to the root
causes of such highly pathogenic viruses. Michael Greger, M.D., the
director of public health and animal agriculture for the Humane
Society of the U.S., lays the blame on the rise of industrial animal
Dr. Greger is a general practitioner, founding member of the
American College of Lifestyle Medicine, and served as an expert
witness in defense of Oprah Winfrey at the infamous “meat
defamation” trial. In his upcoming book Bird Flu: A Virus of Our Own
Hatching (forthcoming from Lantern Books in 2006), Dr. Greger
explores the dangers of factory farming on public health and its
role in the emergence of new infectious diseases.
Sangamithra Iyer had a chance to ask Dr. Michael Greger about all
the buzz around bird flu.
Can you tell us a little bit about the current avian
Avian influenza has existed in nature for a million years as an
innocuous intestinal water- borne virus of wild ducks. It doesn’t
hurt the ducks and the ducks don’t hurt the virus. Human influenza
started just a few thousand years ago particularly with the
domestication of poultry—wild ducks in China.
Every year there is a global influenza outbreak, but it tends to
only kill the elderly, infirm and infants, because they don’t have
well developed immune systems. Although in the U.S., the influenza
may kill tens of thousands of people every year, every few decades a
strain arrives that can kill people in the prime of their lives. The
1918 pandemic killed between 50 and 100 million people around the
globe. And now we are looking down the barrel of perhaps an even
worse pandemic, with the current bird flu H5N1 virus.
What is the current death toll from this virus?
The human death toll stands at less than 100 people. So while it
has ferocity, it still has not mutated into easy human
transmissibility via a handshake or a sneeze. But essentially every
leading public health authority on the planet, from the World Health
Organization to the Centers for Disease Control, view this as
inevitable, a pandemic of influenza triggered by bird flu killing
millions of people—between two million and a billion people across
What role do you see factory farming as contributing to
When you have tens of thousands of chickens overcrowded in filthy
football field size sheds, beak-to-beak in their own waste, one
should not be surprised that these are veritable breeding grounds
for emerging infectious diseases.
One can trace H5N1 to the explosion of intensive poultry
production in Southeast Asia and the developing world in general.
Over the last few decades, meat and egg consumption has really
exploded and led to mass industrial animal agriculture and
transport—the perfect environment for breeding a super flu virus
like this one.
Once this harmless duck virus gets into a broiler shed, all of a
sudden the virus is faced with a problem. It is used to being an
intestinal virus, spread through pond water. But now the virus can
no longer transmit through the pond, and has to find another way to
travel. This virus being RNA-based—as opposed to DNA-based—has a
very sloppy replicating mechanism and mutates at a high rate. It
stops being an intestinal virus and starts spreading throughout the
entire bodies of these land-based fowl, eventually finding the
lungs, and continues to mutate until it’s a virus capable of
airborne transmission. That means it has to be resistant to
dehydration, it has to start killing cells of the respiratory tract
to trigger coughing so it can spread from one chicken to another.
Once you have an airborne virus in one of these broiler sheds, all
of a sudden you have tens of thousands of hosts for this virus to
continue to mutate and get better at killing these animals.
Unfortunately for the human race there is an evolutionary quirk
in that on a molecular level, the respiratory tract of chickens
looks surprisingly like the respiratory tract of humans. As the
virus gets better at killing chickens, the virus gets better at
killing human beings as well. Once that virus makes that final jump
to human-to-human transmission, it will trigger the next global
pandemic of disease.
The blame can really be laid at the feet of intensive poultry
production. This is truly a virus of our own hatching coming back to
Why do you think this started in Asia rather than the
factory farms here in the U.S.?
The reservoir of avian influenza is in domesticated waterfowl.
China produces 90 percent of the goose meat and two-thirds of the
duck meat in the world, and that is [why] all of the last four
pandemics probably originated from southern China. That’s where this
fecal soup of virus is.
Particularly now with industrial agriculture, there is an
unparalleled re-assortment laboratory—a billion people, billions of
domesticated fowl, and the pig population is also such that we have
this nexus for influenza viruses to breed and explode out of.
In Asia, have most of the reported cases been linked to
small family farms or animal factories?
There has never been a case of an outbreak of highly pathogenic
avian influenza (HPAI) on any free-range poultry flock. These
high-grade influenza viruses only seem to be created within these
intensive poultry production environments. So for example in
Minnesota, with the migration south of wild ducks, the free-range
turkey populations would be infected with influenza, but it doesn’t
produce a problem. These are low-grade viruses, and though it might
decrease egg production and growth rates, it doesn’t kill the
turkeys. It cannot spread effectively because it is outdoors.
Sunlight kills influenza. There is good ventilation. They aren’t
living in their waste like they would be when they are crowded
When you have these monocrop chickens bred for carcass quality
and growth rates, and not bred for disease resistance, living in
unsanitary conditions, then these low-grade viruses have the ability
to mutate to high grade which can then go on to kill mammals—pigs,
This new form of industrial agriculture is breeding viruses like
H5N1 and once this factory farmed virus gets created, it can then
re-infect migratory birds. You do have birds flying this virus
potentially across every continent in the world. It didn’t originate
in these birds, or backyard flocks.
There have been measures employed in Europe like
separating birds and pigs, and bringing poultry indoors, to protect
domestic birds from migratory birds. Rather than tackle Concentrated
Animal Feeding Operations (CAFOs), it appears the response is
targeting “free-range” and small family farms. What are your
thoughts and concerns?
Now that the virus is out and is in migratory species, the
rationale is that we have this highly pathogenic species, so we
should take birds indoors. We are assuming a kind of biosecurity
that doesn’t exist around the world. It is very difficult to keep
this virus out of these intensive confinement operations. Once the
virus gets inside, unlike a free-range or pasture setting, it can
mutate at unparalleled rates because it has these hosts crammed in
There has been talk of intensifying surveillance,
stockpiling anti-virals, and vaccine development in the U.S. But is
there any serious discussion about changing how we raise livestock?
At this point, we don’t think it is possible to eradicate H5N1,
since it has spread into wild bird populations. Right now the focus
is on mediating the impact of the current pandemic.
There has been a real negligence in discussing some of the
factors that led to the emergence of this virus in the first place.
Hopefully in the aftermath, there will be real serious consideration
and political will—kind of like a post-9/11 situation, [where] all
of a sudden America sat back and was like wait a second, people
don’t like us? There was some serious consideration of the root
There are other things that aren’t being talked about that could
potentially mediate the spread: eliminate the transport of gaming
cocks, eliminate cock fighting in general, regulate poultry
transport, use less inhumane methods of slaughter and eliminate the
mailing through the postal service of baby chicks from hatcheries.
These things could also have animal welfare implications. But at
this point, there is very little serious consideration of stopping
the pandemic in its tracks.
Given that those working with poultry are the most
vulnerable at first, in the U.S., are any measures being taken to
protect poultry workers from avian flu?
Right now, poultry workers are at an increased risk, but the risk
so far from poultry to human transmission is very low. The virus
still has much to learn in terms of adapting to the human species.
Once it does make that jump, it won’t matter if you work in a
poultry processing plant or a skyscraper, or you’re a meat-eater or
vegan. The disease will spread worldwide.
Can you describe what will happen if you come down with
The problem is that your immune system kills you. The virus
triggers an overreaction of your immune system, which attacks your
lungs and basically turns your lungs into bloody rags and you
essentially drown in your own bloody secretions.
So it is important that people go to their physician and ask for
a prescription of Tamiflu. There are still some limited supplies
left in drug stores. They need to keep it at room temperature.
Within 24-36 hours of initial flu symptoms you take this drug, and a
five-day course should dramatically decrease one’s chances of dying.
Are anti-virals like Tamiflu our only combatant? Will
Tamiflu work on a mutated version of the virus?
As long as the virus is not resistant to that drug. There are two
classes of anti-virals that work against avian influenza. One is
Tamiflu, which is expensive, difficult to manufacture, and there is
not enough to go around. Here in the U.S. we don’t even have enough
Tamiflu to treat one percent of the population. Whether it works or
not, it is not going to have a significant impact.
There was another drug called Amantadine, which is cheap—$10 a
pound, whereas Tamiflu is closer to $10 a pill. You could make tons
of Amantadine and distribute it throughout the world. There is no
way the global South could afford something like Tamiflu. But we
lost Amantadine as a treatment, because poultry farmers in China
were feeding it to their chickens. They were using this human drug
of global importance as a prophylactic to treat healthy uninfected
birds on these industrial farms. There was an exposé done by the
Washington Post—“Bird Flu Drug Rendered Useless” [6/18/05]. So we
lost the best chance we had to treat people on a global scale,
because of this practice that they learned from the U.S. poultry
industry. We are the ones who designed the whole concept of feeding
antibiotics to poultry and other animals crammed in these filthy
conditions. This risky practice is leading to antibiotic resistance.
So what do you do if you don’t have Tamiflu?
If you don’t have Tamiflu—like most of the world and 99 percent of
the U.S.—essentially we are left with hygiene measures. There are
two ways you get the flu, either you inhale it or you touch
something that someone with the flu has touched. So how can you
prevent yourself from getting it? Once the pandemic hits, you stay
out of enclosed places with other people. You stay out of movie
theaters, public transportation, and you wash your hands like
crazy—use alcohol hand sanitizer gels, which are very effective in
killing the virus.
Some people think that since you can’t get the avian flu
from eating chicken, that eating meat is not the problem. What is
First of all, that’s not true. There have been a number of cases
associated with eating chicken and egg products. And not only raw
duck blood pudding, a traditional Vietnamese delicacy, but even
cooked poultry products.
Experiments show that birds inhaling the virus generate the virus
not only in their internal organs, like their lungs, but also within
the muscle fibers themselves. Not only can the virus be on the
external shell of the egg, but the virus also infects the ovaries of
the chickens so the eggs come prepackaged with the virus inside
them. When people use soft boiling cooking techniques, mild
poaching, sunny side up, you may not be adequately heating the food
to a temperature that would kill this virus. Seventy-six million
Americans every year come down with food poisoning, which is caused
by a pathogen that is completely destroyed by proper cooking and
There is also cross contamination in the supermarket or in the
kitchen. That chicken “juice” is a fecal fluid that is absorbed in
the cooling tanks in the processing plant. Once dripped upon a
cutting board, utensil, kitchen sink, kitchen floor, it could
potentially cross-contaminate something that one doesn’t cook, like
And vegetarians really are not safe. They are not exempt from
that fecal fluid dripping on the conveyor belt at the supermarket.
Researchers have swabbed the external packaging of raw chicken
packages in the supermarket and found levels of salmonella and E.
coli on the outside of packaging. You could put your broccoli down
and come down with salmonella.
Even if you have a completely vegan household, and you go out and
get your organic fruits and vegetables, what were those organic
fruits and vegetables fertilized with? They were fertilized with
manure or blood meal and that carries the potential for food-borne
illness, or from fecal contamination anywhere along the supply
chain. So we all need to wash our fruits and vegetables, under
running water, scrub them clean, even if they look fine or they are
Currently under the USDA Organic standards, chicken waste
from factory farms can be used as organic fertilizer. Does that pose
Manure is often composted hoping that it will reach temperatures
that will deactivate most pathogens. But unfortunately it is more of
an art than a science. There continue to be reports of outbreaks of
food-borne illnesses caused by vegetarian foods like bean sprouts
and alfalfa sprouts. When you fertilize alfalfa with manure, some of
the bacteria get into the folds of the seeds, and then when you put
that seed in a warm moist environment to sprout in, it becomes the
perfect growing environment for bacteria, and there have been cases
of E. coli poisoning. All of this food poisoning can be traced back
to industrial animal agriculture, where you have this kind of manure
overload, and unfortunately, it is being disposed of onto our dinner
Is there anything else you want to add?
Truly the most important thing for the future is to really
question industrial poultry production in general. There have been
other industrial practices like strip mining, some petroleum
extractive practices, DDT, and clear cutting, that society has ruled
too environmentally destructive, or pose [too great a] risk to human
health. Even if these practices are more profitable for industry,
these industries need to be regulated. I think the same kind of view
needs to be taken on industrial animal agriculture. With these
emerging infectious diseases, it is too great a threat to human
health to continue these kinds of systems of intensive confinement.
We really have to move towards more sustainable, organic
methods—pasture raised animals if anything. If we are going to
continue to raise animals for slaughter it needs to be done in a way
that minimizes the risk to animal and human health on a global
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