Pandemic Report: Farm to You?

Possible links between swine flu and pig farms deserve more investigation.

Comments (12)
Thursday, November 12, 2009

As swine flu spreads, affecting nearly 6 million Americans by now, spreading fever and discomfort and creating long lines of people waiting for vaccine that's in short supply, reports say that scrutiny of large hog farming operations has slowed down, not speeded up. Virologists and other specialists are alarmed because it's been known for years that workers on these farms are exceptionally likely to show elevated levels of swine flu antibodies.

There are more reasons than one why that fact is disturbing. Cheap meat—low-cost beef, chicken and pork raised on farms so huge that the economics of scale put meat-rich meals within reach of everyone except the very poor—has been the staple of the American diet. The confidence of the carnivorous consumer in meat with the USDA (U.S. Department of Agriculture) logo was almost unbroken for decades until the mad cow disease scandal and the discovery that animal corpses were used as cattle fodder created a market, though hardly more than a niche market, for grass-fed beef raised without antibiotics and growth hormones.

No other scare, except for periodic E-coli outbreaks, has seriously interfered with the year-round pastime of barbecuing, grilling, frying and roasting that makes meat the premier item on the table for most of us. But now comes a swine flu pandemic, and an unwelcome question arises. It is not, as with the beef scares, the question of whether the meat is safe to eat (it is). The question this time is, do the big farms that put cheap pork on our tables increase the risk of infection that can be deadly, especially to children?

What does the average consumer even know about the large, increasingly controversial livestock operations known as CAFOs?

Concentrated Animal Feeding Operation [CAFO] is a legal term for an indoor or outdoor lot or other facility where animals are housed and fed for a total of 45 days in a given year, and where there are no crops or vegetation, including postharvest vegetation such as corn stubble. The important thing about the lack of vegetation is that it means that there is neither anything for the animals to forage on naturally, nor anything to absorb their excrement; labor unions and people living near large outdoor pig CAFOs have complained for years about the tons of excrement that breed clouds of flies, emit odors that have been known to sicken neighbors, and occasionally leak into water supplies. It's a common practice to spray hog waste, without treatment, on fields to serve as fertilizer.

To put CAFOs in perspective, consider that in 1967 there were a million pig farms in the U.S.; in 2002 there were only 114,000, and 57 percent of the nation's swine herd is now produced by four companies. A typical large pig CAFO houses around 2,000 sows. (Iowa, North Carolina, Minnesota, Illinois and Indiana are the major hog-producing states; no farming operation in Massachusetts has over 1,000 hogs, and only four have 500 or more.)

On these very large farms, conditions are ripe for the breeding and transmission of flu viruses, according to Gregory Gray, an M.D. who is director of the Center for Emerging Infectious Diseases at the University of Iowa College of Public Health. "When respiratory viruses get into these confinement facilities, they have continual opportunity to replicate, mutate, reassort, and recombine into novel strains," Gray was quoted as saying in an article published in September in Environmental Health Perspectives. Then, he adds, CAFO workers can pass the virus on to people outside the farms.

The evidence? Three years ago, University of Iowa researchers checked samples of blood from pig farmers, veterinarians and meat processors, comparing them with samples taken from university students and staff. Of the farmers, 17 to 20 percent showed evidence of having been infected with flu, as did 11 to 19 percent of the veterinarians. None of the university students or staff and none of the meat processors did.

An earlier study by Gray found that CAFO workers in Iowa showed 50 times the rate of occurrence of elevated H1N1 (swine flu) antibodies as other state residents. An even more striking finding was that their spouses were also more likely to have the antibodies—25 times more likely—than other people. That strongly suggests that the virus can move from pigs to their caretakers to others outside the farms.


The new outbreak raises that concern to orange alert. "The thing we're concerned about is if this [novel H1N1] virus gets into pigs and then comes back out of pigs into people," Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota, told the Washington Post.

In April, Mexican officials claimed that an outbreak of flu in which a five-year-old girl died of H1N1 infection was caused by conditions at a large hog farm run by a subsidiary of Smithfield Foods. They could not back up the claim with hard scientific evidence. But data gathered by Gray and other specialists shows that links between swine farms and swine flu are worth investigation.

There is, however, no regular, industry-wide surveillance program for swine flu in animals or workers at hog CAFOs. It's still the case that, as the Wall Street Journal reported in May, the government has embarked on "no extensive sampling program of the sort that is used by the federal government to alert it to other animal diseases, such as mad cow disease and bird flu." Some large operations, like Smithfield Foods subsidiary Murphy-Brown, require workers to get flu shots every year. Late in 2008, the CDC funded a $1.5 million program to search out new strains of flu virus in pigs. But this program will only test animals pig farmers submit voluntarily.

Meanwhile the Washington Post reported late in October that efforts to detect the flu virus have "actually decreased in the six months since the H1N1 strain was discovered in California and Mexico in April." Fewer veterinarians are bringing pigs into diagnostic labs in at least three states, Iowa, Kansas and Minnesota, according to the Post; the Iowa State lab just cut three positions for financial reasons.

On the other hand, last week the U.S. Department of Agriculture announced that the H1N1 virus had been found "for the first time in a commercial swine herd," a herd of undisclosed size in an undisclosed location in Indiana. And six H1N1-infected pigs turned up at the Minnesota State Fair in September. Some might have caught the virus from people at the fair, but Gray says that one had been sampled before being unloaded.

Industry spokespeople say their operations are biologically secure without more aggressive government-sponsored inspection. "There are a number of ongoing monitoring activities that take place on a daily basis. If something unusual is going on, we call our veterinarians and they take it from there," Don Butler, public affairs director for Murphy-Brown, told the Advocate. "I am not aware of any peer-reviewed research that links hog operation to the outbreak of H1N1 in anybody."

Elizabeth Wagstrom, a veterinarian with the National Pork Board, says the H1N1 Gray and his colleagues found in pig handlers is an older strain of H1N1 and "not the novel H1N1" that is causing the pandemic. Gray acknowledged in an email to the Advocate that much of his research was done before the current outbreak of H1N1, as is clear by the dates of his studies—but pointed out that the virus found in the hogs at the Minnesota State Fair, in a sampling project financed by the federal Centers for Disease Control, was the novel H1N1. In earlier research, Gray had also said that contact between pigs and humans, in small farms but especially in large ones where that contact is more intense, might give rise to novel flu strains.

The industry also challenges the suggestion that the very large farms may bear more responsibility for the current outbreak of swine flu than smaller farms where pigs are raised. Wagstrom points to a study published early this year by researchers at the Iowa State University College of Veterinary Medicine that found a 20 percent higher instance of H1N1 in pigs from small herds than in pigs from the larger herds as the latter were described in previously published research. It's important to notice, though, that that study only included animals that were sick to begin with.

At the moment, many hog CAFOs fall between cracks in federal regulations. For example, automatic feeding devices and other technology make it possible for seven workers to tend a couple of thousand hogs, but OSHA (the federal Occupational Health and Safety Administration) rules only require routine worker safety inspections at sites employing 11 workers or more. OSHA has a standard, the Bloodborne Pathogens Standard, to monitor the spread of infectious diseases in workplaces. But the BPS does not apply to respiratory diseases, which so far has put swine flu beyond its reach.

Gray wants some of the large farming operations to be opened to academic researchers. Butler told the Advocate that whether Murphy-Brown might allow studies to be done at its farming sites "would depend on who's doing the asking and what kind of intrusion it might impose on our operations."

It's not clear that hog CAFOs are the breeding grounds and transmission centers for swine flu. What is clear is that the issue deserves more examination. Ellen Silbergeld, an epidemiologist who is a professor at Johns Hopkins University's Bloomberg School of Public Health and a former scientific advisor to OSHA, the Environmental Protection Agency and the World Health Organization, has noted that research on so-called zoonotic infections (infections transmitted from animals to humans) has tended to overlook CAFO workers. Silbergeld has received a grant from the National Institute of Environmental Health Sciences to investigate possible relationships between industrial animal production and zoonotic infections.

Meanwhile, workers in pig farming operations need training and protection for their own safety and to assist in preventing epidemics, according to Gray. In "Facing Pandemic Influenza Threats: The Importance of Including Poultry and Swine Workers in Preparedness Plans," published last year in Poultry Science, Gray and another University of Iowa epidemiologist, Ghazi Kayali, point out that sick pigs have been shown to be infected with viruses with human genetic components. People who work with swine, they warn, "have potential to act as 'mixing vessels' from which new strains of influenza viruses can emerge," and as "bridges" through which infection can reach humans. They urge that these workers be at priority to receive vaccines, and be trained to minimize the spread of infection to their families and others beyond the farms.

Comments (12)
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some mistakes: I am not currently an advisor to OSHA, EPA or WHO. We have been funded to conduct our research on this topic
Posted by Ellen Silbergeld on 11.10.09 at 10:29
Hi, I am the author of the Environmental Health Perspectives article, not Dr. Gray . Thanks, Charlie Schmidt
Posted by Charlie Schmidt on 11.10.09 at 11:12
First of all, the correct terminology for this virus is H1N1..not swine flu as the author suggests. The CDC, the USDA and others all encourage the proper usage of the term. Scrutiny of large hog farms has 'gone down' because anyone who looks at the science understands that this flu virus cannot be blamed on large hog farms. There is no proven evidence that this strain of influenza even came from a hog farm. Anyone who makes that distinction is pushing personal propaganda because they don't like the idea of 'factory farms'. Let me tell you something about 'factory farms' (a term coined by the animal rights and environmentalist agenda). These so-called 'factory farms' are actually family farms. Some of these folks may contract with a larger corporation, but many are still independent. Either way, they are farmers with families just like anyone else. The fact is these folks have had to grow larger over time to adapt and survive. Explain to me why in almost any other industry it is okay to grow and prosper, but somehow it is unacceptable in the ag industry? Which, by the way, is an industry that exists to feed not only the people in this country, but people all over the world. It is disheartening to see the agriculture industry continue to be vilified by people who have never set foot on a large, working farm.
Posted by Sarah in Indiana on 11.10.09 at 12:48
The research by Dr. Gray is certainly alarming. And the idea that testing has all but been halted reminds me of a "don't ask, don't tell" strategy. To the folks who defend such practices as confining thousands of animals in cages because man has always grown/consumed "food" animals - They need to understand at no time before has there been a population of 6.8 billion people - Or the kind of intensive animal "husbandry" as now. What worked before, can't possibly hold true today. Animal agriculture may be able to "feed the multitude" (for now) - but such systems are destined to harm us all in the end. Considering the cost to human and environmental health, not to mention the billions of innocent animals - reducing and eliminating "meat" consumption seems to be the prudent course to take.
Posted by Bea Elliott on 11.10.09 at 17:23
Thanks Bea for proving my point and getting to what is at the heart of this issue. From Bea: "Animal agriculture may be able to "feed the multitude" (for now) - but such systems are destined to harm us all in the end. Considering the cost to human and environmental health, not to mention the billions of innocent animals - reducing and eliminating "meat" consumption seems to be the prudent course to take". Personal propaganda with no real facts to substantiate anything. And to your point about understanding population growth...I understand fully. No one understands better than those in agriculture how to feed a growing population. You can't do it by raising animals in your back yard, and you certainly can't do it by dictating that people can't consume animal protein.
Posted by Sarah in Indiana on 11.11.09 at 6:32
Who anywhere is 'dictating' that people can't consume animal protein? I've not seen that in any discussions of this topic, ever. I do see a lot of people trying to educate others about the very real, proven costs of large scale meat consumption in to our health and the planet. Many of these costs HAVE been proven and if you think they are just pure speculation, you need to read up on the topic a bit more. When we are running the planet into the ground with greedy consumption, I'd say it's prudent to look around, tap others on the shoulder and say - "Um, hey, excuse me, but maybe we oughta think about a different way of doing things." It's just common sense. We need to see past the almighty buck and our own precious jobs and livelihoods and look at the big picture. The term factory farming refers to the methodology used to raise the animals, not to who owns the farm. I don't care if a farm is family owned or not, if it has tens of thousand of animals on it being fed by machines in quarters too cramped to even turn around. Sorry but if that's someone's idea of a good business or health practice they have their head in the sand.
Posted by elteegee on 11.11.09 at 21:13
Ms. Kraft appears to have used "valueable" Advocate time and space to attempt to scare the public into avoiding animal cunsumption by pointing out a possible link to hog farms and production facilities as a cause for H1N1 ( not swine flu). This article seems more intent on stopping "animal cruelty" then stating facts about H1N1 and its spread. Animal cunsumption is a natural occurance with humans. Unfortunately, some liberal writers in our area take exception to it along with many other normal functions of humans. She should have spent more time researching and fact finding before throwing this "tripe" out for the rest of us to "swallow". The next time you want to write a story based on hearsay and nonsense, do an article on Soylent Green. I, for one, will be enjoying a big, fat, juicy turkey at Thankgiving dinner with no remorse or worries of contracting bird flu!
Posted by Michael on 11.12.09 at 3:49
Wow, I am totally horrfied by the lack of science, lack of spelling ability, and the high level of ingnorance and arrrogance of the naysayers who despite their pathetic whining, fail to disprove or even debate with non personal anecdotal evidence a single salient point of this article. Note how the specious reasoning by Sarah concentrates on "family" when that is a non-issue. For the longest time, the most polluting car manufacturer was Ford and they were family owned. I especially enjoyed lmao at the ridiculously non-sensical rantings from Michael about this being an anti-meat conspiracy of vegetarians. Clearly someone let their kindergartner too close to the keyboard. And the award for the biggest error and biggest ego goes to... Sarah from Indiana! I quote "No one understands better than those in agriculture how to feed a growing population." Alllow me to retort and say that as the member of a local family that for generations ran a turkey farm, the least likely individual to grasp the big picture are those who are not impartial and immersed in agriculture for their livelihoods and profit. I can suggest dozens of alternate non-emotionally compromised types of individuals who are not personally beholden to agriculture with a far greater intellectual understanding: PhD's in animal husbandry or population genetics, environmental science, biochemistry, population economics, etc... I could go on...
Posted by Greg on 11.12.09 at 6:59
Greg, My family does not own a farm, and I do not depend on raising animals for my livelihood. I know plenty of people with the 'education' you talk about that would agree with me completely on this issue. And since when do you have to have a Ph.D to be credible on an issue? If I want to ask how a car is made, I'll ask the person who actually makes it.. As for emotional arguments...that's all this entire argument is. You think the opposition against agriculture doesn't base their ideas on emotion? You think talking about how animals are raised and feeling bad for them isn't an emotional argument? Particularly when the real science says that there is a reason that animals are raised a particular way. Are you implying that the author was not bringing emotion when she obviously pushed a personal agenda in this article? At least she stated that it is not clear that hog farms are the breeding grounds and transmission center of the flu. That's about the only unbiased statement in the whole story...aside from the fact that a more accurate statement would have been that there is not even an indication that this flu came from a hog operation or is being transmitted by people who work in hog farms. And finally, so what if I am involved and do care about agriculture? Am I not allowed to have a voice? Since when does anything get done by people who are apathetic? All I'm asking is that people look past the personal agendas and take a look at the facts. The facts in this case are that you cannot make a correlation between this flu and hog farms. You simply cannot do it at this point in time....everything that is being said now is speculation by someone who thinks animals should be raised the way they want them to be raised. And finally, check your own spelling before putting down others.
Posted by Sarah in Indiana on 11.12.09 at 12:44
Sarah, I most definitely apologize for my spelling, especially in light of the fact I made fun of other for it, sorry. As for impartial studies (all incomplete to date and ongoing, I summarize from a CIP website with a bit of fact, including scientific American and Nature- "Citing the U.S. Centers for Disease Control, Scientific American points out a starting point that the politicians preferred to ignore: "What is clear thanks to the hard work of virologists is that this particular strain of flu got its genetic start on U.S. hog farms back in the 1990s." Ruben Donis, chief of the molecular virology and vaccines branch at the U.S. Centers for Disease Control and Prevention, stated in an interview with Science magazine: "We know it's quite similar to viruses that were circulating in the United States and are still circulating in the United States and that are self-limiting, and they usually only are found in Midwestern states where there is swine farming." Asked if the virus had swine origins, he replied, "Definitely. It's almost equidistant to swine viruses from the United States and Eurasia. And it's a lonely branch there. It doesn't have any close relatives." For years scientists have known that pigs incubate and mutate viruses and many have warned that "factory farms" where large numbers are kept in close quarters create a perfect breeding ground for the rapid evolution of disease. The massive use of antibiotics means that viruses seek mutations resistant to the medicines. In the past, few cases of swine flu passing to human transmission were reported but it has long been known that it is possible. This virus posed a particular risk because of its virulent capacity for human-to-human contagion. Since the early days of the outbreak, evidence has piled up on the swine origin of the disease. Co-author of a key report in Nature, biologist Michael Worobey said, "The current strain evidently spread without anyone noticing it for 10 years," referring to spread among pig populations. Science News quotes him, concluding, "Across the genome, this is something that came from pigs & We need to spend more energy looking at what's in pigs." The consensus is that the H1N1 virus is a mutant form of swine flu, human seasonal flu, and bird flu. In itself, it is not lethal, but it leads to complications of "atypical pneumonia." The pneumonia is atypical because it occurs out of season and because victims tend to concentrate in the middle age rangeunlike regular pneumonia that picks off the very young and the very old, deaths of this virus tend to be within the 20-40 range. As health organizations struggle to confront the pandemic, animal health experts call for more action on the swine side. Perez notes, "We can do all the surveillance we want in humans, but if we really want to prevent pandemic influenza & a fundamental change in efforts on the animal health side has to be made." This expert piece of advice, repeated on many fronts, has been largely ignored. A June 17 Nature editorial points out one of the main reasons: "& animal-health specialists tend to work through government agencies, whose primary mission is to promote and protect national and international livestock and meat trade. This focus on commerce can sometimes lead to conflicts of interest, as well as some policy positions that border on denial."
Posted by Greg on 11.12.09 at 16:13
Way to go, Greg. Speculation being replaced by research. I like that, and I've been a longtime fan of Scientific American. One of the beauties of Sci-Am is that the researchers often write the articles themselves, not a journalist who's re-interpreting it (no dis meant to Stephanie). Talk about getting it from the source.....! Here's the link and if you want a slew of interesting information, go to and do a search on 'pig farm'.
Posted by JT on 11.12.09 at 19:44
With so many people getting the swine flu lately, it is comforting to know that they are beginning to understand the source and cause of it. Although people are getting sick, they are also coming through just fine for the most part. Still a very big issue considering that babies and younger generations are high risk.
Posted by Apex Professionals on 11.16.09 at 8:41



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