sargent
05-01-2002, 12:56 AM
Game farm diseases threaten wildlife
Tuesday, April 30, 2002
By David Suzuki
Earlier this month, investigators discovered an elk at an Alberta game farm who was infected with a relative of mad cow disease.
The entire herd will have to be destroyed to prevent the disease from spreading, and the incident once again raises questions about the safety of the game-farming industry.
Chronic Wasting Disease (CWD) affects deer and elk. It belongs to a group of fatal brain diseases called transmissible spongiform encephalopathies (TSE), which also includes BSE (mad cow) and its human counterpart, variant Creutzfeldt-Jakob disease (vCJD).
Believed to have originated in a Colorado research farm, CWD has made its way across several states and provinces. It cannot be treated and is untestable in live animals.
One of the most disturbing features of this type of disease, which is caused by an abnormal protein called a prion, is its potential to jump the species barrier. That's what happened in Great Britain, when BSE in cows developed into vCJD in some of the humans who ate infected meat.
While there is currently little evidence to suggest that CWD can infect humans with something similar to vCJD, the connections are too strong to ignore. For example, one study found that, when cows are injected with brain tissue from infected deer, they can develop BSE-like symptoms. And three young Americans, all with a history of eating venison, have developed the classic form of Creutzfeldt-Jakob disease, which is very rare — especially in young people.
So while there is no imminent threat to human health, there is cause for concern. Remember, officials in Great Britain weren't concerned about the sheep disease, scrapie, until it apparently jumped to cows in the form of BSE. Even then, authorities dismissed concerns to human health. Scrapie had never been a threat to humans, so why would BSE? The results of this apathy have been tragic: More than 100 people have died from vCJD so far.
Before the recent outbreak, Alberta had been considered free from CWD. Many biologists are concerned that deer and elk farms, which house large numbers of animals in close quarters, may act as a vector allowing the disease to spread.
Other diseases like tuberculosis are also a problem. An outbreak of tuberculosis on an elk farm in the late 1980s cost Canada its TB-free status and about a billion dollars, according to Agriculture Canada calculations.
As it stands, elk and deer game farms are little more than fenced enclosures — often in areas that are also home to wild populations of the same species. Contact between wild and farmed animals can and does occur. Captives, infected with livestock diseases, escape. And wild animals get into fenced enclosures. Game farming thus literally builds disease bridges between livestock and wildlife.
Fortunately, the prevalence of CWD in Canada is currently low. And the potentially infective tissues (brains, blood, lymphatic glands, stomach, intestines, and bone marrow) of hunted deer and elk are not typically consumed as was the case with cattle in Britain. Antler velvet from game-farm animals, however, is consumed as a dietary supplement. Although there is no evidence linking such consumption to disease in humans, the practice is disturbing.
The problem is much worse in the United States, where hundreds of exposed animals have been shipped to game farms in at least 15 different states. CWD has turned up on more than a dozen U.S. ranches and is also appearing in wild animals. This potential to spread through wild populations has biologists (and hunters) concerned. Health officials in Colorado and Wyoming are advising hunters not to shoot sick-looking deer and to avoid handling brain and spinal material.
Although the industry insists that game farms are strictly regulated, problems with diseases continue to crop up. This poses a very real threat to wildlife and a potential risk to human health as well. Governments need to seriously examine the benefits and risks associated with this industry before the situation gets any worse.
Copyright 2002, David Suzuki Foundation
All Rights Reserved More ENN news
Tuesday, April 30, 2002
By David Suzuki
Earlier this month, investigators discovered an elk at an Alberta game farm who was infected with a relative of mad cow disease.
The entire herd will have to be destroyed to prevent the disease from spreading, and the incident once again raises questions about the safety of the game-farming industry.
Chronic Wasting Disease (CWD) affects deer and elk. It belongs to a group of fatal brain diseases called transmissible spongiform encephalopathies (TSE), which also includes BSE (mad cow) and its human counterpart, variant Creutzfeldt-Jakob disease (vCJD).
Believed to have originated in a Colorado research farm, CWD has made its way across several states and provinces. It cannot be treated and is untestable in live animals.
One of the most disturbing features of this type of disease, which is caused by an abnormal protein called a prion, is its potential to jump the species barrier. That's what happened in Great Britain, when BSE in cows developed into vCJD in some of the humans who ate infected meat.
While there is currently little evidence to suggest that CWD can infect humans with something similar to vCJD, the connections are too strong to ignore. For example, one study found that, when cows are injected with brain tissue from infected deer, they can develop BSE-like symptoms. And three young Americans, all with a history of eating venison, have developed the classic form of Creutzfeldt-Jakob disease, which is very rare — especially in young people.
So while there is no imminent threat to human health, there is cause for concern. Remember, officials in Great Britain weren't concerned about the sheep disease, scrapie, until it apparently jumped to cows in the form of BSE. Even then, authorities dismissed concerns to human health. Scrapie had never been a threat to humans, so why would BSE? The results of this apathy have been tragic: More than 100 people have died from vCJD so far.
Before the recent outbreak, Alberta had been considered free from CWD. Many biologists are concerned that deer and elk farms, which house large numbers of animals in close quarters, may act as a vector allowing the disease to spread.
Other diseases like tuberculosis are also a problem. An outbreak of tuberculosis on an elk farm in the late 1980s cost Canada its TB-free status and about a billion dollars, according to Agriculture Canada calculations.
As it stands, elk and deer game farms are little more than fenced enclosures — often in areas that are also home to wild populations of the same species. Contact between wild and farmed animals can and does occur. Captives, infected with livestock diseases, escape. And wild animals get into fenced enclosures. Game farming thus literally builds disease bridges between livestock and wildlife.
Fortunately, the prevalence of CWD in Canada is currently low. And the potentially infective tissues (brains, blood, lymphatic glands, stomach, intestines, and bone marrow) of hunted deer and elk are not typically consumed as was the case with cattle in Britain. Antler velvet from game-farm animals, however, is consumed as a dietary supplement. Although there is no evidence linking such consumption to disease in humans, the practice is disturbing.
The problem is much worse in the United States, where hundreds of exposed animals have been shipped to game farms in at least 15 different states. CWD has turned up on more than a dozen U.S. ranches and is also appearing in wild animals. This potential to spread through wild populations has biologists (and hunters) concerned. Health officials in Colorado and Wyoming are advising hunters not to shoot sick-looking deer and to avoid handling brain and spinal material.
Although the industry insists that game farms are strictly regulated, problems with diseases continue to crop up. This poses a very real threat to wildlife and a potential risk to human health as well. Governments need to seriously examine the benefits and risks associated with this industry before the situation gets any worse.
Copyright 2002, David Suzuki Foundation
All Rights Reserved More ENN news