May 25, 2018
May 25, 2018

Study Fans New Fears of CWD Threat to Humans

Chronic Wasting Disease (CWD)

Chronic Wasting Disease (CWD) is a controversial topic in Texas.
(Photo courtesy Wyoming Fish and Wildlife)

A RECENT STUDY by Canadian scientists shows macaque monkeys contracted chronic wasting disease (CWD) after eating meat from CWD-positive deer.

According to jsonline, this is the first known transmission of the prion disease to a primate from eating diseased venison. The finding has heightened concerns about human susceptibility to CWD.

“The assumption was for the longest time, that chronic wasting disease was not a threat to human health,” said Stefanie Czub, prion researcher with the Canadian Food Inspection Agency, Her remarks were published Saturday in The Tyee, a Vancouver, British Columbia, magazine. “But with the new data, she said, “it seems we need to revisit this view to some degree.”

This was in contrast to a 2014 study that showed macaques did not contract CWD. However CDC officials did admit there was enough evidence at the time to suggest a low risk of contracting CWD from tissue exposure.

Can people get CWD from eating infected deer? That has not yet been proven, but officials in Canada and the U.S. advise exercising caution.

“Our studies have shown that squirrel monkeys, but not cynomolgus macaques, were susceptible to CWD,” the study reported. “Although these nonhuman primates are not exact models of human susceptibility, they support the data from transgenic mouse studies, in vitro experiments, and epidemiologic evidence that suggest humans are at a low risk of contracting CWD. Nevertheless, it remains sensible to minimize exposure to tissues potentially contaminated with the CWD agent.”

Until recently CWD had only been found in captive deer.

A January 18 inspection of a road-killed whitetail in the Panhandle showed the disease is also present in wild deer at some level according to Texas Parks & Wildlife Department sources.

Texas Parks and Wildlife Department (TPWD) personnel on U.S. Highway 87 between Dalhart and Hartley has tested positive for chronic wasting disease. This marks the first discovery of CWD in a Texas road kill and the first case in a Texas Panhandle whitetail.”

“The road kill was found along the border between the current CWD Containment Zone and Surveillance Zone, and as a result will likely necessitate a precautionary expansion of the Containment Zone,” said Dr. Bob Dittmar, State Wildlife Veterinarian with TPWD.

“We do not believe there’s a need to expand the Surveillance Zone at this time.”

The Texas Parks and Wildlife Commission has approved expansion of the state’s chronic wasting disease (CWD) Panhandle Containment Zone.

The Containment Zone 2 now encompasses that portion of the state within the boundaries of a line beginning where I.H. 40 enters from the State of New Mexico in Deaf Smith County; thence east along I.H. 40 to U.S. 385 in Oldham County; thence north along U.S. 385 to Hartley in Hartley County; thence east along U.S. 87 to County Rd. 47; thence north along C.R. 47 to F.M. 281; thence west along F.M. 281 to U.S. 385; thence north along U.S. 385 to the Oklahoma state line.

“The decision to expand slightly the Panhandle Containment Zone is a direct result of the test positive road kill discovery,” said Dr. Bob Dittmar, TPWD wildlife veterinarian.

“The state’s wildlife disease management response focuses on an early detection and containment strategy designed to limit the spread of CWD from the affected area and better understand the distribution and prevalence of the disease.”

The test positive road kill was among 10,104 deer, elk and other susceptible exotic game animal samples collected from a variety of sources by TPWD personnel for CWD testing during the 2017-18 collection year. In all, TPWD collected 2,203 samples from road kills, with the rest obtained through mandatory and voluntary hunter harvest submissions.

For the 2017-18 collection season, TPWD surpassed its statewide goal of 6,735 CWD samples. Sampling objectives were established by TPWD wildlife biologists based on deer densities within each of the 41 Deer Management Units in Texas and other factors to establish sufficient confidence of detection if CWD were present within those localized populations.

Since 2012 when the state first discovered the disease among mule deer in a remote mountain area along the New Mexico border, Texas has recorded 100 confirmed cases of CWD. Of those, 64 were discovered in captive deer breeding pens, 11 were hunter harvested on breeder deer release sites, and 2 were elk from a breeder release site. Of the remaining positives, 20 were free-ranging mule deer, one was a free-ranging elk and two were free-ranging white-tailed deer.

The topic of CWD is highly controversial in Texas. Deer ranches are concerned the rules pertaining to CWD infringe on their operations, and state officials are concerned about the spread into wild deer populations.

We want to give you all points from both sides on the issue. This study gives no reason to be alarmed, but it does give us reason to dig deeper into the topic. Expect more on it in print and at

—TF&G Staff Report

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