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Maddening Media Misinformation on Biotech and Industrial Agriculture (Part 4 of 5)
By Thomas R. DeGregori
Since Thailand seems to be the focus of the attack by writer Wendy Orent and others on industrial (as opposed to old-fashioned, small-scale) chicken production in Asia -- as the purported origin of avian influenza -- it warrants looking at what the Thai and other scientists have to say in peer-reviewed scientific journals. An article in the Proceedings of the National Academy of Sciences (PNAS) found that:
Wild waterfowl, including ducks, are natural hosts of influenza A viruses. These viruses rarely caused disease in ducks until 2002, when some H5N1 strains became highly pathogenic. Here we show that these H5N1 viruses are reverting to nonpathogenicity in ducks. Ducks experimentally infected with viruses isolated between 2003 and 2004 shed virus for an extended time (up to seventeen days), during which variant viruses with low pathogenicity were selected. These results suggest that the duck has become the "Trojan horse" of Asian H5N1 influenza viruses. The ducks that are unaffected by infection with these viruses continue to circulate these viruses, presenting a pandemic threat (Hulse-Post 2005 -- full citation information for this blog series will appear tomorrow, with the final installment).
This peer-reviewed article had as authors seventeen research scientists in relevant scientific disciplines from Thailand, the U.S., Vietnam, Indonesia, and China. Theirs was a massive, data-rich inquiry in the Asian countries most affected with avian influenza both in birds and in humans. The findings associating avian influenza with free range poultry raising, with mixed flocks of chickens and ducks (and rice paddies), is in line with other scientific studies of the incidence of the disease. Their research demonstrated the more virulent forms of influenza became less virulent in ducks (domesticated and wild), allowing them to be carriers of it without showing any signs of pathology.
The cloacal shedding of virus observed in both pathogenicity groups indicates that long-term shedding is not infrequent or confined to one pathogenicity group. This characteristic is of great consequence especially in free-ranging ducks in that it increases the likelihood of transmission of virus to the environment, to other ducks, and, potentially, to other species. Water in which ducks swim, drink, and eat presents a high exposure risk to humans and domestic chickens. The risk is greatest in the rural areas of affected countries, where domestic ducks and chickens often mingle, frequently sharing the same water supply. The viruses are potentially transmitted to chickens under these conditions (Hulse-Post et al 2005).
The excerpts above are from what is likely to be the PNAS article to which Orent is referring when she states, oddly, that:
Analysis showed that these ducks had been exposed earlier to less virulent strains of H5 and thus were partly immunized before they were infected with H5N1. On this slender basis, coupled with the fact that some domestic ducks infected for experimental purposes don't get sick, the study's authors contend that the findings "demonstrate that H5N1 viruses can be transmitted over long distances by migratory birds."
Note the pejorative, "slender basis" that Orent uses to describe the PNAS research conclusions, as if Orent's argument (that industrial and domestic sources caused H5N1) is built on a mountain of indisputable evidence. If the PNAS article cited above is not the one to which Orent refers (I did not find the exact quote she uses, but I do not expect accuracy from Orent), then there is yet another peer-reviewed scientific article that challenges Orent's certainty that the sole origin of the virulent avian influenza is "industrially produced chicken" and that the sole means of transmission is through the poultry trade. This absolutism is shared by a host of ideologues who have written on the subject.
Real Scientists Lack the Activist/Journalist's Anti-Chicken Bias
It might come as a surprise to the ideologues that in spite of massive evidence supporting the seventeen scientists' "results," they end their article with the statement "the role of the duck in these outbreaks should be investigated further." It is the scientific temperament to do research with an open mind. If the evidence is powerful enough, one acts upon it. Nevertheless, one seeks to keep an open mind about the possibility of other operative factors. On the avian flu issue, the rational scientists try to find the pathways of diffusion and are comfortable with the possibility of multiple mechanisms for transmission, if the evidence supports that conclusion. It goes beyond ideology to crass fanaticism to be willing to accept only one source for avian influenza transmission, no matter how powerful the evidence to the contrary may be.
A major article on avian influenza in Thailand by eight scientists (mostly Thai with affiliations in Thailand, Belgian, the Netherlands, and the Food and Agriculture Organization of the U.N.) in Emerging Infectious Diseases has similar results to the one in PNAS.
Thailand has recently had three epidemic waves of highly pathogenic avian influenza (HPAI); virus was again detected in July 2005. Risk factors need to be identified to better understand disease ecology and assist HPAI surveillance and detection. This study analyzed the spatial distribution of HPAI outbreaks in relation to poultry, land use, and other anthropogenic variables from the start of the second epidemic wave (July 2004-May 2005). Results demonstrate a strong association between H5N1 virus in Thailand and abundance of free-grazing ducks and, to a lesser extent, native chickens, cocks, wetlands, and humans. Wetlands used for double-crop rice production, where free-grazing duck feed year round in rice paddies, appear to be a critical factor in HPAI persistence and spread (Gilbert et al. 2006, 227).
They add: "Areas where both extensive and semi-intensive poultry production systems coexist were believed to be particularly at risk, while larger-scale commercial and industrial poultry plants remained relatively unexposed" (Gilbert et al. 2006, 227). Orent, please note again: "industrial poultry plants remained relatively unexposed." Again, they make the point: "the spatial distribution of these outbreaks does not correspond to areas with high densities of chickens. For example, northeastern Thailand has many native chickens that are not protected by biosecurity measures...Nevertheless, the results substantiate the claim that the geographic pattern of HPAI outbreaks in Thailand is not primarily driven by long-distance transmission between chicken production units or villages, which would have resulted in more outbreaks in areas with high densities of chickens. In the national level analysis, free-grazing ducks constitute the most important poultry-associated variable associated with HPAI in either ducks or chicken (Gilbert et al. 2006, 230-231).
In its discussion, the article goes beyond Thailand to argue that:
All currently affected countries are known for their rice and duck production. For example, similar associations between rice and duck farming occur in Vietnam, where HPAI-affected areas coincide with river delta areas with year-round rice production. With duck populations remaining relatively healthy while excreting sufficient amount of virus to sustain transmission, wetlands with duck-production areas may act as a reservoir from which the virus can spread to distant aquatic duck farms and terrestrial chicken farms (Gilbert 2005, 233).
The Wild Duck: Martyr to the Science Conspiracy
Orent concedes that "some researchers still blame migratory birds for the relentless spread of the bird flu virus," but she will have none of that. She presents no contrary evidence except for quotes from wildlife conservationists and bird experts and organizations such as Grain most noted for their ideological zealotry. The strains of avian influenza that have moved eastward in to Russia, Europe, and parts of Africa have been linked to wild birds, 5,000 of which died at Qinghai Lake in western China. But never fear, Grain claims that there are "commercial poultry farms in the region" that are probably to blame. This claim has been widely echoed, but I have yet to see of any studies done at the commercial farms to verify this thesis. Orent's experts further claim
that the disease spread from Qinghai to southern Siberia during the summer months when birds do not migrate, and that it moved east to west along railway lines, roads, and international boundaries, not along migratory flyways (Orent 2006).
This presumption is offered as an established fact that Orent uses to attack an "increasingly hysterical world" that "targets wild birds" as the culprits. One can download from the World Health Organization's webpage a periodically updated H5N1 avian influenza timeline of major events. One finds that geese and swans have carried the disease eastward, and if one plots the many locations where it has turned up, including an island in the Baltic Sea, one would find it difficult to find the railway lines and international boundaries -- so how are they relevant? -- but I guess one can always find roads, even in Russia.
Orent does correctly quote world-renowned epidemiologist (and ACSH Advisor) Michael Osterholm at the University of Minnesota contending that the "single greatest risk to the amplification of the H5N1 virus, should it arrive in the United States through migratory birds, will be in free-range birds...often sold as a healthier food, which is a great ruse on the American public" (Orent 2006). She quotes him in the context of a critique of how "the commercial poultry industry, which caused the catastrophe in the first place, stands to benefit most" from it. Orent seems to have a problem with anyone or any organization that is knowledgeable about the disease and its transmission. Forcing free range chickens indoors has been particularly difficult for Orent and other anti-modernists to accept, now that it has been proposed for the UK and Europe.
A British Echo
Joanna Blythman had an article in The Guardian (London) that covers many of the same points as Orent, using the same "facts" and the same or similar sources. Like Orent, she believes that free range chicken producers are victims of the disease created by industrial chicken production and will be doubly victimized if free range producers are forced to put them indoors. Even before the avian influenza outbreak, caged chickens were already the source of diseases. "Pathogenic bugs such as salmonella, campylobacter, and Newcastle disease are already endemic among factory-farmed poultry. Half the British chickens on supermarket shelves tested by the Health Protection Agency in 2005 were contaminated with multi-drug-resistant strains of the potentially deadly E. coli bug" (Blythman 2006). This is true, but the same studies or similar studies in the UK found the same rate of infection among free range and organic chickens (BBC 2001a and BBC 2001b). And at least one of the studies found that while 50% of the conventionally grown chicken had campylobacter, it was almost 100% for the free range (BBC 2002).
Chickens that roam outdoors are more likely to carry food poisoning bacteria than those reared indoors, according to research from the University of Bristol. Free range and organic flocks are twice as likely to carry the bacteria than conventional flocks, the study found... [T]he organic campaign group, the Soil Association dismissed the research as incomplete (BBC 2002).
There were similar findings in studies in Denmark. "In fact a study in Denmark among chickens has shown that organic birds had even higher rates than non-organic birds" (BBC 2003). In searching the Internet, I could find no studies in which the organic or free range chickens had a lower incidence of disease. Add in that high levels of dioxin (likely to be naturally occurring dioxin) have been found in free range chickens and in their eggs in the UK and in Germany (BBC 2005). There is a body of literature on the disease problems involved in raising chickens outdoors. Outdoors, there is a large number of possible disease contacts such as rats, in addition to wild birds.
In various accounts of these studies in articles on the BBC web site, the Soil Association was allowed to respond. The movement clearly was aware of the studies mentioned above and their findings. Assuming that Blythman is honest, one has to ask what filtration system is operating in these movements such that their supporters can make fools of themselves by using data in a manner that is totally misleading and would be considered dishonest if done knowingly.
Bird Flu, One More Nail in Modernity's PR Coffin
To Orent, though, "the real victims of industrially produced, lethal H5N1 have been wild birds, an ancient way of life, and the poor of the Earth, for whom a backyard flock has always represented a measure of autonomy and a bulwark against starvation." By being in denial about any role that wildlife may have played in avian influenza except as victim, the defenders of wildlife make it more difficult to engage in control practices that could help "the poor of the Earth" (MacKenzie). One wonders whether Orent or others making these grand proclamations in defense of the "poor of the Earth" have ever done anything to help them except to issue ringing declarations of sympathy. Many of the NGOs have a record of opposing the very practices that the poor need, often in the name of protecting them.
Debora MacKenzie wonders why there is denial of any role for the dissemination of avian influenza by wildlife. (MacKenzie incidently agrees with the Orent and Blythman on a number of points but is open to a more complex understanding of the problem.)
A clue as to what this [underlying set of attitudes about wild birds] might be emerged in April at the first, hastily arranged World Migratory Bird Day in Nairobi, Kenya, which was described by its conservationist organizers as happening "at a time when migratory birds are being unfairly portrayed solely as the harbingers of death and disease" -- an absurdly exaggerated claim. Another critic said: "The real question is not, are wild birds to blame, but why are wild birds being blamed?" In other words, this isn't about evaluating evidence, it's about building conspiracies.
The only reason I can think of for all this is that we are dealing with a community acting more on faith and emotion than reason. For them, birds are, by definition, innately pure and transcendent -- too pure to carry anything as mundane or dirty as a virus. Given this attitude, you can understand their denial, but they are doing neither wild birds nor humans any favors (MacKenzie 2006).
(More to come on these topics tomorrow. See the prior entries in the series here and here and here. Go here for Part 5.)
Thomas R. DeGregori is a Professor of Economics at the University of Houston and a member of the Founders Circle of the American Council on Science and Health. His homepage is: http://www.uh.edu/~trdegreg
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