Chronic Wasting Disease Spread
In Many Ways - Study

Casper Star-Tribune

DENVER (AP) -- A new study shows chronic wasting disease can spread through environmental contamination and not just animal-to-animal contact, a finding that could change the way experts fight the ailment.
The study, published in the online edition of the journal Emerging Infectious Diseases, also suggests that chronic wasting outbreaks could last longer than previous models projected.
The study confirms a long-held theory that deer and elk can contract the fatal disease through land contaminated by the carcasses or excrement of infected animals.
"The experimental findings show that we need to consider several potential exposure routes when attempting to control this disease," said University of Wyoming professor Elizabeth Williams, a co-author of the report.
Previous projections on how the disease would spread were based only on animal-to-animal transmission. Those models predicted the disease would begin to decline once the number of infected animals dropped.
The new study suggest the rate of decline could be much slower.
In the experiment, researchers confined three sets of healthy deer in separate paddocks. In one paddock they included a live deer infected with chronic wasting disease, in another they included carcasses with the disease and the third paddock had previously contained infected deer.
In each paddock, some of the healthy deer contracted the disease.
The researchers said infection rates in their experiment may be higher than in the wild because of the enclosed environment, but conditions simulated the wild.
"Although live deer and elk still seem the most likely way for CWD to spread geographically, our data show that environmental sources could contribute to maintaining and prolonging local epidemics, even when all infected animals are eliminated," said Colorado Division of Wildlife veterinarian Michael Miller, another report co-author.
Chronic wasting creates sponge-like holes in the brains of deer or elk, causing the animal to grow thin, act abnormally and die. It is a prion disease, similar to mad cow disease.
There never has been a known case of it being transferred to humans or livestock, but people are cautioned not to eat the brain, nervous tissue or lymph glands of the animals.
The disease has been found in a dozen U.S. states and Canada.
Study findings will also be published in the June issue of Emerging Infectious Diseases.
Copyright © 2004 by the Casper Star-Tribune published by Lee Publications, Inc., a subsidiary of Lee Enterprises, Incorporated



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