The link between avian flu and intensive agriculture

Author:
Debra Probert
Publication:
Globe and Mail
Publication Date:
November 23, 2005

 

The inexorable increase in avian influenza hysteria is leading governments locally and internationally to consider increasingly radical measures to contain the perceived threat of a human pandemic. The swift and lethal response of the Canadian Food Inspection Agency to the duck infected with a harmless H5 virus in British Columbia is a good example and the recent discovery that people have been infected in China can only exacerbate this situation. These measures include keeping all domestic birds indoors, away from wild birds; culling flocks at the first sign of even a harmless strain of flu; draining wetlands; culling wild populations of birds and stockpiling masses of expensive drugs of questionable efficacy. But before we impose such drastic methods, we should heed the root cause of the problem.

Many strains of avian influenza circulate in wild birds at low levels, without causing illness. These are LPAI, or Low Pathogenicity Avian Influenza bugs. Natural selection plays an important role in regulating wildlife populations. A virus enters a population and removes those that are unable to defend themselves from the attack. Biological diversity is the key to the population’s survival. Animals that survive infection and reproduce will likely pass on their ‘resistant’ or ‘tolerant’ genes to future generations. This does not always mean they are immune, but they may be asymptomatic (carriers of the disease). In the case of avian influenza, for example, wild waterfowl (ducks and geese) have undergone such a process. They are now carriers, but do not necessarily show signs of the disease. Given time and successive generations, nature has taken its course.

The conditions in modern intensive poultry farms are very different from those found in nature. There is no question that the virulence and rapid spread of the H7N3 outbreak in British Columbia, Canada in February, 2004 was exacerbated by the intensification and limited genetic diversity of the birds. Almost all the chickens bred for meat in North America are the same breed. They are bred specifically to crave food and to grow at an accelerated rate while they are kept in sheds with near-continuous artificial light. They spend their entire short lives eating, sleeping and defecating in the same confined space before they are sent to slaughter at between 34 and 42 days old. Egg-laying hens present a similar case. They are bred specifically to lay large numbers of eggs – over 300 a year. They are kept five to seven per cage, in barns of up to 35,000 birds. These birds are nearly identical genetically. Under these conditions, natural immunity is virtually impossible.

In contrast, backyard and organic flocks are typically more diverse and more closely emulate nature. During the outbreak in British Columbia in 2004, of 553 backyard flocks tested, only one tested positive for the virus, and that was after testing negative twice. The positive test came three days after the depopulation of an infected commercial farm 400 metres away.

What does this have to do with the spread of the virus in south-east Asia, China and Europe? Why, in apparently more open systems, have avian flu outbreaks been increasing? Every night the television news pundits show us pictures of small farms and open markets with lots of different species. But is this the reality?

The answer is not common knowledge. The Food and Agriculture Organization of the United Nations (FAO) lists six contributing factors affecting the spread of high-path viruses in Asia. Three of these have to do with an increase of poultry populations and intensification of poultry production.

The rise of poultry consumption across the world is exponential. In North America, per capita consumption was 33.8 pounds in 1970. In 2003, it had risen to 111.9 pounds. Poultry consumption in India has doubled in the last five years. In developing countries, poultry consumption rises with economic prosperity. Consequently, Asia has seen an explosion of industrial poultry farming and is expected to eventually dominate global production. Not only have developed countries exported their insatiable appetite for animal products, they have also exported intensive poultry and egg production technology.

However, this technology is being exported into a potentially devastating environment. In developing countries, a dramatic increase in intensive poultry production is often combined with poor hygiene and little or no biosecurity. Domestic ducks are turned out to feed with wild birds in rice fields, then confined in tight quarters with other poultry at night. Domestic birds from different areas travel long distances, sometimes hundreds of miles, and are brought together in poultry markets crowded with people. Government corruption is rife, with cover-ups to protect business interests. National and international monitoring systems are ignored or inadequate. According to the FAO, the spread of avian flu from Pakistan to China may have been facilitated by the rapid increase in pig and poultry operations and the massive geographic concentration of livestock in Thailand, Vietnam and China.

So even though the conditions vary, the root cause is the same. In both developed and developing countries, intensively-farmed poultry populations are a jackpot for viruses. The cramped quarters makes transmission from host to host extremely easy. The diversity that is key to the survival of wild bird populations does not exist among domestic flocks and animals’ immune systems are compromised, rendering them susceptible to infection. Sloppy hygiene and lack of regulatory oversight, along with a lack of international accountability make an already serious situation deadly. What is an economically devastating problem in North America becomes a world-wide life-threatening one in developing countries.

Before we make scapegoats of wild birds; before we resort to extreme measures that can and will have a permanent effect on nature as we now know it; before we make the wealthy drug companies even wealthier by paying a premium for mass-produced drugs that probably won’t work, we need to assess the devastation wreaked across the world by the unsustainable appetite for animal protein. The intensification of animal agriculture seriously compromises the welfare of animals that are its victims. It is also ruining the environment and our health. Now it threatens to destroy millions of human lives. Is it worth it?

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