Ticks may spread chronic wasting disease among Wisconsin deer – ScienceDaily

CWD is caused by pathogens called prions and can be transmitted from deer to deer through contact with prion-contaminated soil or infected bodily fluids such as urine, saliva, blood and faeces. Prions, which cause disease in animals and humans, encourage the misfolding of certain proteins, especially in the brain, preventing them from performing their normal functions. Over time, CWD prions can cause severe brain damage in deer, ultimately leading to death.

Much of CWD’s research has focused on the role soil plays in spreading deadly neurological diseases in deer. But Heather Inzarako, a researcher at the Wisconsin Cooperative Wildlife Research Unit at the Madison, Wisconsin Department of Forest and Wildlife Ecology, was interested in other potential environmental and behavioral means of transmission.

“Deer live secret lives, but we don’t get to see everything they do,” says Inzaraco.

She began to wonder what was bothering the deer and that it might have something to do with CWD. Ticks were perfect as potential culprits of parasites to investigate.

Ticks, of course, serve the purpose of sucking the blood of their host. Inzaraco wondered if ticks that feed on blood from CWD-infected deer could host prions, and if so, might contain enough prions to spread the disease. I started.

This question became even more interesting when we discovered that the most common non-aggressive social behavior performed by deer is allogrooming.

“Deer groom each other and groom themselves to go places they can’t get to,” says Inzaraco. “If they’re grooming each other and they’re doing it to get rid of ectoparasites, [such as ticks], probably eating ectoparasites, so that might be a problem. ”

First, she had to show that ticks could take up and retain these prions when feeding on CWD-infected blood. She designed an experiment to do just that.

“You might think it would be easy to get a tick to suck blood, but in the lab, ticks are surprisingly noisy,” says Inzaraco.

She was able to determine that ticks not only carry prions in their blood meal, but may also carry enough material to infect another animal with CWD. After confirming that this phenomenon can occur in the laboratory, it’s time to see what happens in the natural environment.

Inzaraco partnered with the Department of Natural Resources to study ticks from deer collected by hunters and submitted for CWD testing. Of her 176 tick-infected deer she investigated, 15 also tested positive for her CWD. Inzaraco collected ticks from infected deer and tested the blood in them to quantify the amount of prions the ticks carried.

She determined that these swollen, wild ticks, like those in the lab, carried contagious levels of prions and could mechanically transmit disease.

“They’re like little CWD tic-tac-toe games that could possibly be eaten by deer,” says Inzaraco.

The study did not test whether prion-carrying ticks infect other deer.

A better understanding of how CWD spreads will help improve disease management. Although it’s impractical to treat all wild deer with tick repellants, Inzaraco believes that better land management could help manage tick numbers.

For example, native plant communities live adjacent to each other, and proper management of the area to continue the natural fire regime has been shown to limit tick populations, but invasiveness Ticks can multiply more easily in more fragmented, unbalanced ecosystems with more vegetation, she says.

Inzaraco said ticks could be used as a way to test for CWD in both wild and farmed deer. Current diagnostic or screening methods include invasive sample collection from animals or post-mortem tissue sampling of animals. Testing for ticks taken from deer may not be as accurate as testing tissue samples, but it provides a better understanding of where the disease is impacting deer populations across the state. can be a useful tool for

Inzaraco also believes her research will help improve the ecosystems we all depend on, especially the state’s hunters.

“We are all intimately connected to the functioning of ecosystems and the biodiversity of those ecosystems,” she says. “That’s what drives my desire to learn and practice good science every day, so that we can continue to live on this planet, be free from disease, and have healthy animals and healthy animals.” requires efforts to protect natural heritage.” Healthy functioning ecosystems. ”