http://www.pewtrusts.org/news_room_detail.aspx?id=37968
Contact: Ralph Loglisci, 202.223.2996 Washington, DC - 04/11/2008 - The same techniques that have increased the productivity of modern animal agriculture are also contributing to a number of growing public health concerns, a panel of experts told Congress today. For pictures and video see the website http://www.hsus.org/farm/news/ournews/swine_flu_virus_origin_1998_042909.html April 30, 2009 Crowded conditions on factory farms create breeding grounds for new viruses. ©iStockphoto
Members of the Pew Commission on Industrial Farm Animal Production (PCIFAP) enumerated the hazards to human health associated with today’s large-scale industrial farm animal production (IFAP). These hazards include exposure to harmful contaminants, the spread of infectious diseases, and a growing resistance to the antibiotics commonly used to treat those diseases.
Commissioners explained that some of the dominant practices used in IFAP facilities set the stage for these threats to emerge. In IFAP systems, large numbers of animals are raised together, usually in confinement buildings, increasing human exposure to dangerous pathogens from animals or the large quantity of animal wastes generated in such conditions. Animal waste, which harbors a number of pathogens and chemical contaminants, is usually left untreated, often sprayed on fields as fertilizer, raising the potential for contamination of air, water, and soils. In one recent example, farm animal run-off from IFAP facilities was among the suspected causes of a 2006 E. coli outbreak in which six people died and more than 250 were sickened.
There are numerous known “zoonotic” diseases -- infectious diseases that can be transmitted between humans and animals. Due to the large numbers of animals housed in close quarters in typical IFAP facilities, there are many opportunities for animals to be infected by several strains of pathogens, leading to increased chance for a strain to emerge that can infect and spread in humans.
Another concern stems from the use of large quantities of antimicrobials in animal feeds used in IFAP facilities. While intended to produce ideal market weights and consistency among livestock and poultry, these drugs have been found to spur the mutation of many forms of bacteria and other pathogens into forms that are increasingly resistant to once-reliable antimicrobial and antibiotic drugs. Humans are increasingly exposed to a number of these resistant strains for which commonly used antibiotics are no longer effective.
Several recent and high profile recalls involving E. coli O157:H7, as well as Salmonella enteritidis serve as graphic reminders of the risk of food borne illnesses – risk that are greatly amplified by the scale and methods common to IFAP. All areas of meat, poultry, egg, and dairy production can potentially contribute to zoonotic disease and food contamination, with dire consequences if they do reach human hosts. A 1999 report estimated that E. coli O157:H7 infections caused approximately 73,000 illnesses, leading to over 2,000 hospitalizations and 60 deaths each year in the United States. Animal manure, especially from cattle, is the primary source of these bacteria, and major routes of human infection include consumption of food and water contaminated with animal wastes.
IFAP facilities also cause occupational health impacts. Workers and operators are exposed to toxic dust and gases that may result in temporary, and in some cases chronic, respiratory irritation, including bronchitis, non-allergic asthma-like syndrome, mucous membrane irritation, and non-infectious sinusitis. In addition to dust, other irritants, such as gases, are generated inside the building from decomposition of animal urine and feces. A 1997 study of chronic (non-IFAP or IFAP) occupational exposures to hydrogen sulfide, a byproduct of some animal waste processing methods, found that such exposures might lead to neuropsychiatric abnormalities including impaired balance, hearing, memory, mood, intellectual function, and visual field performance.
Finally, communities surrounding IFAP facilities are also vulnerable to health hazards from air emissions and water pollution. These hazards include respiratory symptoms, disease and functional impairment, as well as neurobehavioral symptoms. Those with weaker immune systems, such as young children and the elderly, are especially vulnerable. One study showed that North Carolina residents who lived in the vicinity of intensive swine operations exhibited higher rates of tension, depression, anger, reduced vigor, fatigue, and confusion than those who did not live near the facility.
Current monitoring systems in IFAP are inadequate to protect the public from the harmful effects of contamination or disease. Animal identification and meat product labeling practices make tracing infections to the source difficult or impossible. Moreover, IFAP may be legally exempt from mandatory health monitoring, disease reporting and surveillance programs in many cases, so IFAP workers who may carry disease-causing organisms usually are not identified.
“While many features of industrial farm animal production have provided plentiful food products to consumers, there are unacceptable health risks associated with IFAP that must be confronted,” said Dr. Michael Blackwell. “The public should not have to pay for high productivity with their health.”
The Pew Commission was convened in 2005 to study the impacts of dramatic changes in animal agriculture in America over the past 40 years. The decline of the family farm and the concentration of the industry into a relative few large corporations has meant greater efficiency and lowered costs for producers. But this shift has also brought environmental, public health, and socioeconomic problems. Today’s event was part of a series of Capitol Hill issue briefings on these risks and challenges that will culminate in the public release on April 29 of a set of recommendations to address them. The PCIFAP’s two-year study encompassed site visits to production facilities across the country, consultation with industry stakeholders, public health, medical, and agriculture experts, public meetings, and peer-reviewed technical reports.
For more information visit the Pew Commission on Industrial Farm Animal Production Web site.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@CDC Confirms Ties to Virus First Discovered in U.S. Pig Factories
By Michael Greger, M.D.
Factory farming and long-distance live animal transport apparently led to the emergence of the ancestors of the current swine flu threat.
A preliminary analysis of the H1N1 swine flu virus isolated from human cases in California and Texas reveals that six of the eight viral gene segments arose from North American swine flu strains circulating since 1998, when a new strain was first identified on a factory farm in North Carolina.
This analysis, first released by Columbia University’s Center for Computation Biology, has now been reportedly confirmed by researchers at the University of Edinburgh, St. Jude's Children's Research Hospital and virologist Ruben Donis, chief of the molecular virology and vaccines branch at the U.S. Centers for Disease Control and Prevention. Dr. Robert Webster, the director of the U.S. Collaborating Center of the World Health Organization, and considered the "godfather of flu research,"[1] is reported as saying "The triple reassortant in pigs [first discovered in the U.S. in 1998] seems to be the precursor."
Plaguing People and Pigs
The worst plague in human history was triggered by an H1N1 avian flu virus, which jumped the species barrier from birds to humans[2] and went on to kill as many as 50 to 100 million people in the 1918 flu pandemic.[3] No disease, war or famine ever killed so many people in so short a time. We then passed the virus to pigs, where it has continued to circulate, becoming one of the most common causes of respiratory disease on North American pig farms.[4]
For media interviews with Dr. Michael Greger, please contact Liz Bergstrom at ebergstrom@humanesociety.org or 301-258-1455. ©The HSUS
In August 1998, however, a barking cough resounded throughout a North Carolina pig factory in which all the thousands of breeding sows fell ill.[5] A new swine flu virus was discovered on that factory farm, a human-pig hybrid virus that had picked up three human flu genes. By the end of that year, the virus acquired two gene segments from bird flu viruses as well, becoming a never-before-described triple reassortment virus—a hybrid of a human virus, a pig virus, and a bird virus—that triggered outbreaks in Texas, Minnesota, and Iowa.[6]
Within months, the virus had spread throughout the United States. Blood samples taken from 4,382 pigs across 23 states found that 20.5% tested positive for exposure to this triple hybrid swine flu virus by early 1999, including 100% of herds tested in Illinois and Iowa, and 90% in Kansas and Oklahoma.[7] According to the current analysis, it is from this pool of viruses that the current swine flu threat derives three-quarters of its genetic material.[8]
Tracing the Origins of Today's Virus
The year of emergence, 1998, was the year North Carolina's pig population hit ten million, up from two million just six years earlier.[11] Concurrently, the number of pig farms was decreasing, from 15,000 in 1986 to 3,600 in 2000.[12] How can five times more animals be raised on almost five times fewer farms? By crowding about 25 times more pigs into each operation.
In the 1980s, more than 85% of all North Carolina pig farms had fewer than 100 animals. By the end of the 1990s, operations confining more than 1,000 animals controlled about 99% of the state's pig population.[13] Given that the primary route of swine flu transmission is thought to be the same as human flu—via droplets or aerosols of infected nasal secretions[14]—it's no wonder experts blame overcrowding for the emergence of new flu virus mutants.
Intensive Crowding and Long-Distance Transport
Starting in the early 1990s, the U.S. pig industry restructured itself after Tyson's profitable chicken model of massive industrial-sized units. As a headline in the trade journal National Hog Farmer announced, "Overcrowding Pigs Pays—If It's Managed Properly."[15] The majority of U.S. pig farms now confine more than 5,000 animals each. A veterinary pathologist from the University of Minnesota stated the obvious in Science: "With a group of 5,000 animals, if a novel virus shows up it will have more opportunity to replicate and potentially spread than in a group of 100 pigs on a small farm."[16]
Dr. Robert Webster, one of the world's leading experts of flu virus evolution, blames the emergence of the 1998 virus on the "recently evolving intensive farming practice in the USA, of raising pigs and poultry in adjacent sheds with the same staff," a practice he calls "unsound."[17] North Carolina is also one of the nation's largest poultry producers, slaughtering nearly three-quarters of a billion chickens[18] and confining enough hens to produce nearly 3 billion eggs.[19]
Once the new viral mutant appeared in 1998, the rapid dissemination across the country has been blamed on long-distance live animal transport.[20] In the United States, pigs travel coast to coast. They can be bred in North Carolina, fattened in the corn belt of Iowa, and slaughtered in California.[21] While this may reduce short-term costs for the pork industry, the highly contagious nature of diseases like influenza (perhaps made further infectious by the stresses of transport) needs to be considered when calculating the true cost of long-distance live animal transport.
"A Recipe for Disaster"
The remaining two gene segments of the H1N1 swine flu virus now spreading in human populations around the world appear to come from a swine flu viral lineage circulating in Eurasia, where similar conditions may be to blame. "Influenza [in pigs] is closely correlated with pig density," said a European Commission-funded researcher studying the situation in Europe.[22] As such, Europe's rapidly intensifying pig industry has been described in Science as "a recipe for disaster."[23] Some researchers have speculated that the next pandemic could arise out of "Europe's crowded pig barns."[24] In Europe in 1993, a bird flu virus had adapted to pigs, acquiring a few human flu virus genes and infected two young Dutch children, displaying evidence of limited human-to-human transmission.[25]
The European Commission's agricultural directorate warns that the "concentration of production is giving rise to an increasing risk of disease epidemics."[26] Concern over epidemic disease is so great that Danish laws have capped the number of pigs per farm and put a ceiling on the total number of pigs allowed to be raised in the country.[27]
No such limit exists in the United States or in Mexico. The fact that the first confirmed human case of swine flu appeared in close proximity to the largest pig factory in Mexico, which slaughters nearly a million pigs a year (out of a country-wide total of 15 million), may not have been a coincidence.
Warnings Unheeded
The public health community has been warning about the risks posed by factory farms for years. More than five years ago, in 2003, the American Public Health Association, the largest and oldest association of public health professionals in the world, called for a moratorium on factory farming.[28] In 2005, the United Nations urged that "[g]overnments, local authorities and international agencies need to take a greatly increased role in combating the role of factory-farming," which, they said, combined with live animal markets, "provide ideal conditions for the [influenza] virus to spread and mutate into a more dangerous form."[29]
Last April, the Pew Commission on Industrial Farm Animal Production released its final report. The prestigious, independent panel chaired by a former Kansas Governor and including a former U.S. Secretary of Agriculture, former Assistant Surgeon General, and the Dean of the University of Iowa College of Public Health, concluded that industrialized animal agriculture posed "unacceptable" public health risks: "Due to the large numbers of animals housed in close quarters in typical [industrial farm animal production] facilities there are many opportunities for animals to be infected by several strains of pathogens, leading to increased chance for a strain to emerge that can infect and spread in humans."[30]
Specific to the veal crate-like metal stalls that confine breeding pigs like those on the North Carolina factory from which the first hybrid swine flu virus was discovered in North America, the Pew Commission asserted that "[p]ractices that restrict natural motion, such as sow gestation crates, induce high levels of stress in the animals and threaten their health, which in turn may threaten human health."[31] Unfortunately we don't tend to "shore up the levees" until after the disaster, but now that we know swine flu viruses can evolve to efficiently transmit human-to-human we need to follow the Pew Commission's recommendations to abolish extreme confinement practices like gestation crates as they're already doing in Europe, and to follow the advice of the American Public Health Association to declare a moratorium on factory farms.
A "Reservoir of Viruses" in the U.S.
With massive concentrations of farm animals within whom to mutate, these new swine flu viruses in North America seem to be on an evolutionary fast track, jumping and reassorting between species at an unprecedented rate.[32] This reassorting, Webster's team concludes, makes the 65 million strong U.S. pig population an "increasingly important reservoir of viruses with human pandemic potential."[33] "We used to think that the only important source of genetic change in swine influenza was in Southeast Asia," said Christopher Olsen, a molecular virologist at the University of Wisconsin, Madison. Now, "we need to look in our own backyard for where the next pandemic may appear."[34]
Dr. Michael Greger is director of public health and animal agriculture for The Humane Society of the United States.
References
[1] Council on Foreign Relations. 2005. Session 1: Avian flu-where do we stand? Conference on the Global Threat of Pandemic Influenza, November 16. http://cfr.org/publication/9230/council_...uenza_session_1.html.
[2] Belshe RB. 2005. The origins of pandemic influenza-lessons from the 1918 virus. New England Journal of Medicine 353(21):2209-11.
[3] Johnson NPAS, Mueller J. Updating the accounts: global mortality of the 1918–1920 "Spanish" influenza pandemic. Bull Hist Med. 2002;76:105–15.
[4] Zhou NN, Senne DA, Landgraf JS, et al. 1999. Genetic reassortment of avian, swine, and human influenza A viruses in American pigs. Journal of Virology 73:8851-6. http://birdflubook.org/resources/ZHOU8851.pdf.
[5] Wuethrich B. 2003. Chasing the fickle swine flu. Science 299:1502-5. http://birdflubook.org/resources/WUETHRICH1502.pdf.
[6] Zhou NN, Senne DA, Landgraf JS, et al. 1999. Genetic reassortment of avian, swine, and human influenza A viruses in American pigs. Journal of Virology 73:8851-6. http://birdflubook.org/resources/ZHOU8851.pdf.
[7] Webby RJ, Swenson SL, Krauss SL, Gerrish PJ, Goyal SM, and Webster RG. 2000. Evolution of swine H3N2 influenza viruses in the United States. Journal of Virology 74:8243-51.
[8] Rabadan, R. 2009. Influenza A (H1N1) "swine flu": worldwide (04) [1] ProMED Digest 2009. 28 April. Volume 2009 : Number 196. http://www.promedmail.org/pls/otn/f?p=2400:1001:1580522401053605::NO::F2400_P1001_BACK_PAGE,F2400_P1001_
PUB_MAIL_ID:1000,77250.
[9] Webby RJ, Swenson SL, Krauss SL, Gerrish PJ, Goyal SM, and Webster RG. 2000. Evolution of swine H3N2 influenza viruses in the United States. Journal of Virology 74:8243-51.
[10] Environmental Defense. 2000. Factory hog farming: the big picture. November. http://www.edf.org/documents/2563_FactoryHogFarmingBigPicture.pdf.
[11] Duke University Center on Globalization, Governance and Competitiveness. 2006. Hog farming overview. February 23. http://www.soc.duke.edu/NC_GlobalEconomy/hog/overview.php.
[12] North Carolina Department of Agriculture and Consumer Services. 2001. North Carolina agriculture overview. February 23. http://ncagr.com/stats/general/livestoc.htm.
[13] Wuethrich B. 2003. Chasing the fickle swine flu. Science 299:1502-5. http://BirdFluBook.org/resources/WUETHRICH1502.pdf.
[14] Brown IH. 2000. The epidemiology and evolution of influenza viruses in pigs. Veterinary Medicine 74:29-46. http://BirdFluBook.org/resources/Brown29.pdf.
[15] 1993. Overcrowding pigs pays-if it's managed properly. National Hog Farmer, November 15.
[16] Wuethrich B. 2003. Chasing the fickle swine flu. Science 299:1502-5. http://BirdFluBook.org/resources/WUETHRICH1502.pdf.
[17] Webster RG and Hulse DJ. 2004. Microbial adaptation and change: avian influenza. Revue Scientifique et Technique 23(2):453-65.
[18] USDA. 2009. Poultry Slaughter 2008. Annual Summary. http://usda.mannlib.cornell.edu/usda/current/PoulSlauSu/PoulSlauSu-02-25-2009.pdf
[19] USDA. 2009. Chickens and Eggs 2008 Summary. http://usda.mannlib.cornell.edu/usda/current/ChickEgg/ChickEgg-02-26-2009.pdf
[20] Wuethrich B. 2003. Chasing the fickle swine flu. Science 299:1502-5. http://birdflubook.org/resources/WUETHRICH1502.pdf.
[21] Shields DA and Mathews KH Jr. 2003. Interstate livestock movements. USDA Economic Research Service: Electronic Outlook Report from the Economic Research Service, June. usda.mannlib.cornell.edu/reports/erssor/livestock/ldp-mbb/2003/ldp-m108-01.pdf.
[22] MacKenzie D. 1998. This little piggy fell ill. New Scientist, September 12.
[23] Ibid.
[24] Delgado C, Rosegrant M, Steinfeld H, Ehui S, and Courbois C. 1999. Livestock to 2020: the next food revolution. Food, Agriculture, and the Environment Discussion Paper 28. For the International Food Policy Research Institute, the Food and Agriculture Organization of the United Nations and the International Livestock Research Institute. http://ifpri.org/2020/dp/dp28.pdf.
[25] Webster RG, Sharp GB, and Claas CJ. 1995. Interspecies transmission of influenza viruses. Americal Journal of Respiratory and Critical Care Medicine 152:525-30.
[26] MacKenzie D. 1998. This little piggy fell ill. New Scientist, September 12, p. 1818.
[27] Ibid.
[28] American Public Health Association. 2003. Precautionary moratorium on new concentrated animal feed operations. Policy number 20037. www.apha.org/advocacy/policy/policysearch/default.htm?id=1243.
[29] United Nations. 2005. UN task forces battle misconceptions of avian flu, mount Indonesian campaign. UN News Centre, October 24. un.org/apps/news/story.asp?NewsID=16342&Cr=bird&Cr1=flu
[30] Pew Commission on Industrial Farm Animal Production. 2008. Expert panel highlights serious public health threats from industrial animal agriculture. Press release issued April 11. www.pewtrusts.org/news_room_detail.aspx?id=37968. Accessed August 26, 2008.
[31] Pew Commission on Industrial Farm Animal Production. 2008. Putting meat on the table: industrial farm animal production in America. Executive summary, p. 13. www.ncifap.org/_images/PCIFAPSmry.pdf. Accessed August 26, 2008.
[32] Wuethrich B. 2003. Chasing the fickle swine flu. Science 299:1502-5. http://birdflubook.org/resources/WUETHRICH1502.pdf.
[33] Webby RJ, Rossow K, Erickson G, Sims Y, and Webster R. 2004. Multiple lineages of antigenically and genetically diverse influenza A virus co-circulate in the United States swine population. Virus Research 103:67-73. http://BirdFluBook.org/resources/webby67.pdf.
[34] Wuethrich B. 2003. Chasing the fickle swine flu. Science 299:1502-5. http://BirdFluBook.org/resources/WUETHRICH1502.pdf.
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