Scientists at the Pennsylvania University School of Medicine are enlisting dogs in the ongoing struggle to manage chronic wasting disease (CWD) in deer, elk, moose, and other cervids. Through meticulous training, the research team found that three pet dogs could smell the presence or absence of CWD in deer feces. If applied on a broader scale, trained CWD dogs could be used as a useful strategy to help quell the spread of the always-fatal neurological disorder.

“We were already quite certain that the dogs could detect the volatile organic compounds released by chronic wasting disease in feces,” Amritha Mallikarjun, a postdoctoral researcher in Penn Vet’s Working Dog Center and a lead author on the study, told Penn Today. “Not only did we show this was possible, but we also answered a second, more interesting question, which is: Can they detect the disease in a simulated field setting, as they would if we were using the dogs to find the disease in the landscape of a forest or on a deer farm?”

Based on the study results, the answer to that question appears to be: Most of the time. For the more controlled portion of the experiment, the researchers used a scent wheel equipped with eight separate ports. Some of the ports were filled with CWD-positive scat samples provided by the U.S. Department of Agriculture, while the other ports were loaded with negative samples. The dogs passed by the negative samples 90-95 percent of the time, spending most of their time examining the CWD-infected samples.

During field testing, the samples were placed in glass jars with mesh lids and partially buried in different spots throughout a large, privately-owned field. The dogs detected eight of the 11 CWD-positive samples used in the field experiment.

Researchers in the Pennsylvania University study collaborated with the Pennsylvania Department of Agriculture and the Pennsylvania Game Commission. The state agencies hope that trained CWD dogs could one day be used to detect the presence of CWD in wild, free-ranging herds—as well as deer being reared on agricultural operations.

Just knowing that the disease exists in a particular area would give game managers an opportunity to detect an outbreak in its earliest stages rather than dealing with it after it’s already run through a given deer population. Without the aid of disease-sniffing dogs, CWD is impossible to detect in wild deer, unless those deer are harvested by hunters and submitted for sampling.

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CWD has been on the rise in North America since it first emerged on the landscape in captive deer in Colorado in the 1960s. It is spread when an infected animal sheds malformed proteins, also known as prions. These infectious proteins can persist on surfaces like dirt and leaves for months or years at a time. When a healthy deer comes into contact with infectious prions, it can contract the deadly disease. In recent years, CWD has been detected in more and more southeastern whitetail states like Mississippi, Louisiana, North Carolina, Alabama, and Tennessee. It was first detected in Pennsylvania in 2012.

“Given the amount of time that we trained these dogs and the novel environment, not to mention the fact that these are pet dogs and not trained search dogs, our results are promising,” said Mallikarjun. “As we move forward and work with dogs that are specifically trained to search in a field setting and devote their entire lives to detecting this odor, they are going to do an even better job.”