Who gets CWD

Who gets CWD

David Sparks Ph.D.
David Sparks Ph.D.
Chronic Wasting Disease (CWD) is a contagious neurological disease affecting deer, elk and moose. It causes a characteristic spongy degeneration of the brains of infected animals resulting in emaciation, abnormal behavior, loss of bodily functions and death. I talked with Retired professor of veterinary medicine at Texas A&M, Dr. Don Davis.

CWD belongs to a group of diseases known as transmissible spongiform encephalopathies (TSEs). Within this family of diseases, there are several other variants that affect domestic animals:It is not known exactly how CWD is transmitted. The infectious agent may be passed in bodily emmissions. Transmission is thought to be lateral (from animal to animal). Although maternal transmission (from mother to fetus) may occur, it appears to be relatively unimportant in maintaining epidemics. The minimal incubation period between infection and development of clinical disease appears to be approximately 16 months. The maximal incubation period is unknown, as is the point at which shedding of the CWD agent begins during the prolonged course of infection.

Retired professor of veterinary medicine at Texas A&M, Dr. Don Davis was asked by the Texas Deer Association to do a comprehensive review of the literature concerning chronic wasting disease or CWD. "The premier organization representing deer and elk farmers across the United States, the American Cervid Alliance, released a scientific report regarding Chronic Wasting Disease (CWD). The report outlines the disease's transmission, geographic distribution, and effect on deer populations (or lack thereof). A few key findings of the report are that CWD is prevalent in less than one percent in over one million deer tested nationally, and to date not one single case of CWD has been found in humans. Today the American Cervid Alliance, which represents deer and elk farmers across the United States, released a scientific report on the current state of Chronic Wasting Disease research. The report is prepared by disease and deer experts Donald S. Davis, PhD; Kenneth Waldrup, DVM, PhD; Greg Stewart, DVM, PhD; and James Kroll, PhD.

 

The 31-page report summarizes the current state of research about CWD, including the disease's transmission, geographic distribution, and effect on deer populations (or lack thereof). Among its findings: 

·         CWD is a fairly rare disease with a prevalence less than 1% in the over million deer tested nationally over the last 20 years, and a prevalence of 11.2% in the 196 CWD positive counties in the 23 CWD positive States?

·         CWD is neither a "wild deer" disease nor a "captive deer" disease but can be found in both. There are 3 states with CWD only in captive deer herds and 8 states with CWD only in wild free-ranging populations. Based on USDA positive test prevalence numbers, CWD is more common in wild deer and elk than in captive cervids.?

·         In spite of the expenditure of over $100,000,000 of public funding, and thousands of animals killed, none of prevention, control, or eradication methods employed by the various States since 1998 have been shown to be effective in either preventing increased prevalence of CWD or the increased geographic distribution.?

·         To date, not one single case of CWD has been found in humans despite tens of thousands of CWD test positive deer and elk being ingested by people.?

·         Much CWD research and reporting is couched in terms such as "believe" and "likely." These are subjective terms that should be avoided. Science is, or should be, based on demonstrable data.

A full copy of the report is available here: http://www.americancervidalliance.org/userfiles/File/Current-Scientific-Knowledge-About-CWD-Davis-et-al-April-20181.pdf

 

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