Writer: D'Lyn Ford
LAS CRUCES - There's no scientific evidence that animals other than deer and elk can contract chronic wasting disease under natural conditions, says a New Mexico State University wildlife expert.
Earlier this month, the fatal brain disease was diagnosed in two deer from a January hunt in the Organ Mountains east of Las Cruces. The discovery of the two new cases pushed the total number of infected deer found in or near White Sands Missile Range in southern New Mexico to six during the past year.
The find has also once again led some to link the brain malady more closely with mad cow disease than scientific evidence currently supports, said Jon Boren, a wildlife specialist with NMSU's Cooperative Extension Service. "Chronic wasting disease is a type of transmissible spongiform encephalopathy, a group of diseases that includes mad cow disease in cattle and scrapie disease in sheep," he said. "But chronic wasting disease is significantly different."
So far, the only cattle and sheep that have developed chronic wasting disease were under intensive experimental conditions, Boren said. Some animals contracted the disease only after researchers directly injected brain matter from an infected animal into the subject's brain, he said.
Chronic wasting disease attacks the brains and spinal cords of deer and elk. The neurological disease creates sponge-like holes in a deer's brain, causing the animals to become disoriented and wither away as they quit feeding.
"In all probability, transmission from one animal to another is through body fluids like feces, urine or saliva," Boren said. "Animals that are crowded or confined also have a greater chance of encountering the body fluids of other animals, and therefore a higher likelihood of becoming infected."
In contrast, mad cow disease in Europe is believed to have spread through cattle feed containing recycled meat and bones from infected ruminant animals. Meat and bone meal is not fed to cattle in the United States. The bovine illness is thought to cause the fatal human variant Creutzfeldt-Jakob disease.
U.S. health and wildlife officials clearly aren't seeing and don't expect a repeat of Great Britain's devastating mad cow experience of the 1990s when entire herds had to be destroyed, but many states do monitor for chronic wasting disease and warn hunters to take precautions to minimize risk.
"We need to keep in mind that there's no evidence that chronic wasting disease has or can spread to humans," Boren said. "However, it just makes sense to take some precautions. Don't shoot, handle or consume any animal that appears sick, and if you observe a sick animal, contact the New Mexico Department of Game and Fish."
New Mexico is home to about 80,000 deer and 70,000 to 90,000 elk, said Kerry Mower, a wildlife disease specialist with the New Mexico Department of Game and Fish.
Over the last 35 years, chronic wasting disease has been detected in 11 states and Canada. First identified in 1967 in Colorado, the disease has been found in free-ranging deer and elk in United States and the Canadian province of Saskatchewan, as well as at commercial deer and elk ranches in six states and two Canadian provinces.
© 2013 New Mexico State University Board of Regents
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