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Bird Flu - Chicken Run
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“If you get a [H5 or H7] virus into a high-density poultry operation and give it a period of time, generally a year or so, then you turn that virus into a highly virulent virus. That’s what always happens….”2005 Canada’s National Manager of Disease Control within the Food Inspection Agency seems to agree: “Just passing the virus to 3,000 or 4,000 chickens is enough to change a harmless virus into something more pathogenic.”5006 “It is high-density chicken farming that gives rise to highly-virulent influenza viruses,” Brown concluded. “That’s pretty clear.”2007
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The Netherlands outbreak showed not only that intensive chicken farms may brew a virus capable of human-to-human transmission, but that such a strain can arise in an advanced industrialized country with modern, high-tech poultry facilities.2020
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Bird Flu - Monoculture
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We can learn from past mistakes. In the early 1970s, for example, the U.S. corn industry developed “Tcms” corn, a highly profitable strain adapted for large-scale farming. Only after 85% of the nation’s seed corn acreage was covered with the new variety did the industry realize that the strain also happened to be particularly susceptible to a rare form of leaf blight fungus that then wiped out areas of the U.S. corn belt.1932
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Biodiversity is biosecurity. Even the most virulent of diseases typically do not kill all infected individuals, in part due to natural inborn genetic variability. In the wild, natural selection takes advantage of this variation to pass disease-resistant qualities to the next generation.1937 The diversity in nature tends to ensure that some individuals will survive whatever comes along. Artificial selection for production qualities undermines Mother Nature in two ways, by inbreeding unnaturally elevated egg production and fleshiness over fitness, as well as by reducing the genetic diversity that can act as resistance insurance against present and unforeseen threats of disease.1938
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Bird Flu - Chicken Surprise
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That’s why we’ve been so concerned about pigs. Ducks have the 2,3 linkages, humans have the 2,6 linkages, and pigs have both. So, in a pig, the duck virus could theoretically accustom itself to our receptors and burst throughout the human population.1586 Unfortunately for the human race, researchers recently discovered that chickens have human 2,6 receptors in their lungs as well.1587
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Just a single point mutation may change a virus that binds duck 2,3 receptors to a virus that binds human 2,6 receptors.1594 The researchers who resurrected the 1918 virus found that the receptor binding site on the virus differed from the binding site of its presumed avian precursor by just one or two tiny amino acid substitutions, presumably all it needed to go human.
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Bird Flu - Acute Life Strategy
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In nature, the influenza virus has existed for millions of years as a harmless intestinal waterborne infection of waterfowl, particularly ducks.1510 The duck doesn’t get sick, because the virus doesn’t need to make the duck sick to spread. In fact, it may be in the virus’s best interest for the bird not to get sick so as to spread farther. Dead ducks don’t fly.
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“Humans have altered the natural ecosystems of birds through captivity, domestication, industrial agriculture, and nontraditional raising practices. This has created new niches for AI [avian influenza] viruses….”1537
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Bird Flu - Viral Swap Meets
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Chickens and ducks, geese and quail are crammed into small plastic cages stacked as much as five high in these live animal “wet” markets. Distressed birds defecate on those below them.1353 Feathers and feces are everywhere.1354 So are blood and intestines.1355 According to the World Health Organization, the birds are often slaughtered on the spot, “normally with very little regard for hygiene.”1356 “The activities of humans have affected the evolution of influenza,”
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“And birds under stress are much more prone to disease.”1383
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Bird Flu - Hog Ties
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The sialic acid receptors lining the intestines of ducks have what are called alpha-2,3 linkages, whereas human lungs have sialic acid receptors with alpha-2,6 linkages. Influenza strains tend only to bind effectively with one type of receptor or the other. This difference in receptor compatibility helps form a species barrier, keeping the bird strains in the birds and the human strains in the humans.1286
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in August 1998, a barking cough resounded throughout a North Carolina pig farm in which all the thousands of breeding sows fell ill. An aggressive H3N2 virus was discovered, the type of influenza that had been circulating in humans since 1968. Not only was this highly unusual—only a single strain of human virus had ever previously been isolated from an American pig population—but upon sequencing of the viral genome, researchers found that it was not just a double reassortment (a hybrid of human and pig virus, for example) but a never-before-described1291 triple reassortment, a hybrid of three viruses—a human virus, a pig virus, and a bird virus.
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Bird Flu - Pandora’s Pond
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Analyzing the genome of H5N1, scientists now suspect that the 1997 outbreak arose when an H5 goose virus combined with an N1 duck virus with quail acting as the mixing vessel (another species “raised under battery conditions”1253 ). The virus then jumped from quail to chickens and then from chickens to humans.1254
In 2001, in what seems to be a separate emergence, that same H5 goose virus combined with an N1 duck virus in a duck, then jumped to chickens directly, bypassing the quail.1255 In both cases, the H5 virus first isolated from a farmed domestic goose population in Guangdong province was found,1256 surprisingly, to be already partially adapted to mammals.1257 Scientists speculate that this could have been a result of the virus acclimating to a pig, especially, perhaps, given Asia’s unique fish-farming technique.1258 -
The influenza virus found naturally and harmlessly in ducks’ intestines are excreted in the water. The chickens may drink the virus-laden water. The pigs then eat the virus-laden chicken feces. The ducks then drink the pond water contaminated by the virus-laden pig excrement and the cycle can continue.
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Bird Flu - Last Great Plague
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Because of its extreme mutation rate, influenza is a perpetually emerging disease. Anthony Fauci, the NIH’s pandemic planning czar, calls it “the mother of all emerging infections.”1249
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Bird Flu - Big Mac Attack
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The changes in the digestive tracts of cattle fattened in feedlots with energy-dense grain to marble the flesh with saturated fat (instead of natural cattle foodstuffs like hay) has been blamed for the emergence of E. coli O157:H7. Grain-fed beef may be more tender, but grass-fed beef may be safer.1184
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Bird Flu - Animal Bugs Forced to Join the Resistance
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The majority of the antibiotics produced in the world go not to human medicine but to prophylactic usage on the farm.1194 This may generate antibiotic resistance.
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Bird Flu - Offal Truth
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farm practice is the continued feeding of slaughterhouse waste, blood, and excrement to livestock to save on feed costs.1074
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The livestock industry has experimented with feeding newspaper, cardboard, cement dust, and sewer sludge to farm animals.1076
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Bird Flu - Stomaching Emerging Disease
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Veterinarian and academician David Waltner-Toews writes in his book Food, Sex, and Salmonella, “The most serious problems [with foodborne disease] invariably come back to the willingness of pureblooded capitalists to take risks with other people’s lives.”1064
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Medical researchers at the University of Minnesota published a clue to the mystery in the April 2005 issue of the Journal of Infectious Disease. Taking more than 1,000 food samples from multiple retail markets, they found evidence of fecal contamination in 69% of the pork and beef and 92% of the poultry samples as evidenced by E. coli contamination. More surprising was that more than 80% of the E. coli they recovered from beef, pork, and poultry were resistant to one or more antibiotics, and greater than half of the samples of poultry bacteria “were resistant to >5 drugs!”
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Bird Flu - Back to the Dark Ages
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Treatment may be given to sows for metritis, mastitis, and for diseases such as erysipelas and leptospirosis. In most indoor herds antibiotic treatment starts soon after birth. Piglets will receive drugs for enteritis and for respiratory disease. From weaning (usually three weeks) all piglets are gathered, mixed and then reared to finishing weights. Weaners usually develop post-weaning diarrhea caused by E. coli which occurs on day 3 post-weaning…. Post-weaning diarrhea is quickly followed by a range of other diseases. Glasser’s Disease (haemophilus parasuis) occurs at 4 weeks, pleuropneumonia at 6–8 weeks, proliferative enteropathy from 6 weeks and spirochaetal diarrhea and colitis at any time from 6 weeks onward…. At 8 weeks the pigs are termed growers and moved to another house. Here they will develop enzootic pneumonia, streptococcal meningitis (Streptococcus suis), and, possibly, swine dysentery. Respiratory disease may cause problems until slaughter.979
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Bird Flu - Pigs Barking Blood
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Raising pigs is not new in Malaysia, but intensive industrial production is. The Leong Seng Nam farm, where the epidemic broke out, confined more than 30,000 pigs. The Nipah virus, like all contagious respiratory diseases, is a density-dependent pathogen,925 requiring a certain threshold density of susceptible individuals to spread, persist, and erupt from within a population.926
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Even industry groups like the American Association of Swine Veterinarians blame “[e]merging livestock production systems, particularly where they involve increased intensification” as a main reason why zoonotic diseases are of increasing concern. These intensive systems, in addition to their high population density, “may also generate pathogen build-ups or impair the capacity of animals to withstand infectious agents.”949
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Bird Flu - America’s Soft Underbelly
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Given that “highly crowded” animals are reared in “extreme proximity” in the United States, one infected animal could quickly expose thousands of others.887
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Herds that have been subjected to such modifications—which have included everything from sterilization programs to dehorning, branding, and hormone injections—have typically suffered higher stress levels that have lowered the animals’ natural tolerance to disease from contagious organisms and increased the viral and bacterial “volumes” that they normally shed in the event of an infection.888
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Bird Flu - Shipping Fever
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“Transport of livestock is undoubtedly the most stressful and injurious stage in the chain of operations between farm and slaughterhouse,” leading to significant “loss of production.”866 This stress impairs immune function, increasing the animals’ susceptibility to any diseases they might experience on their prolonged, often overcrowded journeys.867
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Bird Flu - Wild Tastes
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“All considered,” wrote two chief wildlife veterinarians in the Council on Foreign Relations journal Foreign Affairs, “at least a billion direct and indirect contacts among wildlife, humans, and domestic animals result from the handling of wildlife and the wildlife trade annually.”842
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Growing populations and increasing demands for wildlife meat exceed local supplies of these animals.859 This has resulted in an enormous (and largely illegal) transboundary trade of wildlife and the setting up of intensive captive production farms in which wild animals are raised under poor sanitation in unnatural stocking densities. These animals are then packed together into markets for sale. All of these factors favor the spread and emergence of mutant strains of pathogens capable of infecting hunters, farmers, and shoppers.860
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Bird Flu - AIDS: A Clear-Cut Disaster
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“Mostly these days,” wrote one prominent medical microbiologist, “it is man’s intrusion on the natural environment which is the all-important key to emerging viruses.”803
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Developers chopped America’s woods into subdivisions, scaring away the foxes and bobcats who had previously kept mouse populations in check. Animal ecologists recover some seven times more infected ticks from 1- and 2-acre woodlots than lots of 10 to 15 acres. The pioneer in this area concluded, “You’re more likely to get Lyme disease in Scarsdale than the Catskills.”810
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Bird Flu - The Plague Years
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Australia’s National Centre for Epidemiology and Population Health says we shouldn’t be surprised by the recent explosion in zoonotic disease given recent environmental changes. “We need to think ecologically,” he said. “These viruses are trying to evolve.”785 Just as plants and animals in the wild try to adapt to new environments to spread their species, viruses also expand to exploit any newly exposed niches. “Show me almost any new infectious disease,” said the executive director of the Consortium of Conservation Medicine, “and I’ll show you an environmental change brought about by humans that either caused or exacerbated it.”786
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Two centuries ago, Edward Jenner, the founder of modern vaccines, proposed that the “deviation of man from the state in which he was originally placed by nature seems to have proved him a prolific source of diseases.”788 This observation dates back to the 2nd century, when Plutarch argued that new classes of diseases followed profound changes in the way we live.789 The same can be said for animals. “Something is not right,” reflects Professor Shortridge. “Human population has exploded, we are impinging on the realms of the animals more and more, taking their habitats for ourselves, forcing animals into ever more artificial environments and existences.”790
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Bird Flu - “Wherever the European has trod, death seems to pursue the aboriginal.”
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Medical historians have long conjectured that the reason there were so many plagues in Eurasia was that “crowd” diseases required large, densely-populated cities, unlike the presumed small tribal bands of the Americas. But that presumption turned out to be wrong. "New world" cities like Tenochtitlan were among the most populous in the world.775
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James Linzel's Public Lists (13)
- Assignment 1: Origins of the Universe
- Assignment 2: Origins and Fate of Stars
- Assignment 3: History of Western Astronomical Thought
- Assignment 4 - Our Solar System
- Atomic Theory
- Bird Flu Book
- Climate Change
- Climate Resources
- Ecologically Friendly Homes
- Evolution: Transitions, Genetics, Evidence
- Important Chemists
- RCSB Protein Database
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