Collaborate on Chronic Wasting Disease
By Alisyn Amant
Together, researchers from the UW School of Veterinary Medicine and the Wisconsin Department of Natural Resources (DNR) are working to uncover new information about chronic wasting disease (CWD) in white-tailed deer populations. Building on decades of collaboration between the two units, the partnership proved essential to the success of the study.
Marie pinkerton, Clinical Professor of Anatomical Pathology at the School of Veterinary Medicine, provides autopsy (autopsy) services for the research project, which began in 2017 and is in its fifth year of data collection.
To begin with, wildlife scientists and field team trappers captured and attached humane GPS collars to a sample of deer population in southwestern Wisconsin, the region of the state where MDC is the most widespread.
From there, electronic signals follow the fate of the animals. When an animal stops moving, the research team retrieves the animal. Their goal is to better understand how CWD affects deer populations and eventually build a singular data model to provide a standard basis for CWD research that does not currently exist.
The project is the largest study ever undertaken by MNR.
Since the CWD was found in Wisconsin in 2002, it has had an impact on both wild and captive deer. Stakeholders are working to fight and control the disease through a multi-pronged response plan, including research and testing. Of 266,528 wild deer sampled in Wisconsin since 2002 (most of them collected during the hunting season), 8,242 have tested positive for CWD.
“Is CWD causing deer population decline?” This is our big question: at what prevalence do we see an impact on the population. How prevalent is the disease itself causing deer population decline? “
CWD is an infectious prion disease of the deer family. Variant prions, which cause CWD, are proteins that aggregate around normal prion proteins in the body, ultimately changing their shape and causing abnormal cellular reactions. Although the disease is primarily found in the neural tissue of the brain, it can migrate anywhere in an animal’s body.
“These aggregates accumulate in the body, in the brain and cause all kinds of cascading consequences,” explains daniel storm, deer researcher for the MRN and principal investigator of the project. “It causes a cascade of disease or ailments and ultimately kills the deer. It is always fatal. No cure, no cure.
Some animal studies suggest that CWD poses a risk to certain types of non-human primates, such as monkeys, which eat meat or come in contact with fluids from animals infected with CWD. These studies raise concerns that there could be a risk to people as well. Since 1997, the World Health Organization has recommended preventing the agents of all known prion diseases from entering the human food chain.
Hunters from all over Wisconsin can submit a sample of their deer for a CWD test. Testing through the DNR is free for deer slaughtered in Wisconsin. For more information, visit dnr.wisconsin.gov.
He stressed the infectious nature of the disease. Animals transmit it through saliva, urine, feces and other channels.
“Is CWD causing deer population decline?” That’s our big question: at what prevalence do we see an impact on the population, ”says Storm. “How prevalent is the disease itself causing a decline in the deer population?” “
Pinkerton had previously expressed his interest in wildlife research to Storm and other MNR colleagues. So when Storm invited her to participate in this study, she immediately agreed.
When deceased animals are collected, the DNR sends them to Pinkerton for an autopsy to determine the exact cause of death. Her in-depth knowledge of pathology and autopsy techniques has made her invaluable to the research team and to finding answers to Storm’s pressing questions.
“She has a ton of expertise that we don’t have. He’s someone who has spent his entire career teaching and doing animal pathology work, ”explains Storm. “This is why we are so lucky to have Marie and the vet school. She is a very willing and enthusiastic partner. So it was really, really great for us because it gave us a wealth of information that we wouldn’t have had otherwise.
Although the study is still ongoing (it will end in 2022), Storm and Pinkerton have both noticed trends in the data collected so far. “One of the first trends we established is that deer carrying CWD are 30% more likely to die,” says Pinkerton. “Which sounds like something you’d say, ‘Yeah, that’s an obvious thing. But it’s good to also have the figures to be able to prove it.
Veterinary residents who pursue advanced pathology training at the school also got involved in the process. They were able to implement the Wisconsin idea firsthand, using their expertise in service to the state while gaining broader knowledge. “It was certainly an eye-opening teaching experience for them in terms of what the pathology of wildlife involves,” says Pinkerton.
“She has a ton of expertise that we don’t have. He is someone who has spent his entire career teaching and doing animal pathology work. This is why we are fortunate to have Marie and the veterinary school. It has been really, really great for us because it has given us a wealth of information that we wouldn’t have been able to get otherwise.
These types of partnerships have proven invaluable, whether it’s slowing the spread of CWD or addressing emerging threats that could impact the state’s deer and other wildlife. More recently, this fall, MNR confirmed cases of epizootic hemorrhagic disease, or EHD, in deer in Juneau and La Crosse counties. While the agency does not believe the disease poses a significant threat, it has encouraged the public to remain vigilant and report to the DNR any sightings or deaths of sick or unusual deer.
Additionally, in light of recent research which revealed that hundreds of white-tailed deer tested in Iowa have been infected with the coronavirus, a professor at the School of Veterinary Medicine Tony goldberg is involved with stakeholders in Wisconsin and beyond on next steps. He also spoke to several media outlets about the implications of the deer as a potential transmission reservoir, particularly in the midst of the fall deer hunting seasons. Experts hope the results will encourage the creation of more effective pathogen surveillance systems.
For now, researchers continue to better understand Wisconsin’s deer populations while keeping an eye out for the rest.