There is no evidence that dogs can contract chronic wasting disease (CWD) from eating deer feces, or from any other route of exposure. No dog has ever been diagnosed with CWD, and dogs appear to be among the most prion-resistant mammals studied. That said, deer droppings carry other pathogens worth knowing about if your dog regularly snacks on them during walks or in your yard.
Why Dogs Appear Resistant to CWD
CWD is caused by misfolded proteins called prions that attack the brain and nervous system of cervids (deer, elk, and moose). For a prion disease to jump species, the new host’s own prion protein needs to be structurally compatible enough to misfold in the same way. Dogs have a built-in shield against this: a single amino acid in their prion protein that is different from virtually every other mammal studied.
A 2017 study published in PLOS Pathogens pinpointed this difference. Researchers created transgenic mice carrying the dog version of that amino acid, then injected prions directly into their brains, which is the most aggressive possible route of infection. The mice showed complete resistance to three different prion strains. No clinical disease, no detectable misfolded protein. The researchers concluded that this one amino acid change is likely the primary, if not sole, reason dogs don’t get prion diseases. It’s worth noting that no naturally occurring prion disease has ever been identified in any canid species, including wolves, coyotes, and foxes that routinely scavenge cervid carcasses in CWD-endemic areas.
How Much Prion Is in Deer Feces
Infected deer do shed prions in their feces, urine, and saliva throughout most of the disease course, often long before they show symptoms. However, the concentration of prions in these excretions is low compared to what’s found in brain and nervous tissue. The bigger concern with fecal shedding is environmental accumulation over time. Prions don’t break down easily in soil, so contaminated areas can remain infectious to other deer for years. For a dog, though, even repeated exposure to these low concentrations doesn’t appear to pose a risk given the species barrier described above.
Some scavengers and carnivores, including coyotes and raccoons, may transiently pass prions through their digestive systems and shed them in their own feces after eating contaminated tissue. This is not the same as being infected. The prions simply transit the gut without causing disease. Dogs likely do the same if they consume deer droppings containing trace amounts of prion protein.
Could CWD Strains Evolve to Infect Dogs
This is one area where researchers remain watchful. CWD prions are not static. As the disease spreads through deer populations with varying genetics, new prion strains can emerge with different properties. A CDC-published study identified an emergent strain called H95+ that successfully infected ordinary lab mice, a species normally resistant to common CWD strains. Mice inoculated with the more typical Wisc-1 strain showed no signs of disease after nearly two years, while those exposed to H95+ developed clinical illness including coordination problems, lethargy, and tail rigidity.
This doesn’t mean dogs are at risk today. The canine prion protein’s protective amino acid appears to be a more fundamental barrier than what was overcome in those mouse experiments. But the finding illustrates that CWD is evolving, and the host range of new strains can differ from what scientists previously expected. Surveillance of CWD strain diversity is ongoing for exactly this reason.
Real Risks of Dogs Eating Deer Droppings
While CWD isn’t the concern, deer feces can carry a range of bacteria and parasites that do affect dogs. Salmonella, Campylobacter, E. coli, and Giardia are all shed in wildlife droppings and are capable of causing gastrointestinal illness in dogs. Symptoms typically include diarrhea, vomiting, loss of appetite, and lethargy. Some of these organisms, particularly Campylobacter and certain E. coli strains, can also pass from an infected dog to the humans in the household, making this a practical hygiene issue beyond just your dog’s health.
Deer feces can also contain parasitic larvae and eggs. Depending on your region, this might include liver flukes or various nematodes. Dogs that frequently eat wildlife droppings may benefit from more regular fecal testing at the vet to catch parasitic infections early.
Keeping Your Dog Away From Deer Droppings
If you live in an area with heavy deer traffic, a few practical habits can reduce your dog’s exposure. On walks, keep your dog on a leash in areas where deer droppings are common, and train a reliable “leave it” command. In your yard, scan for and remove deer pellets regularly, especially in the morning when deer tend to have passed through overnight.
One effective approach from dog trainers: teach your dog to come to you immediately after sniffing the ground, using a high-value treat as a reward. Over time, this builds a habit where the dog looks to you instead of investigating (or eating) whatever they’ve found. For dogs with a deeply ingrained habit of eating feces, sometimes called coprophagia, working with a trainer on impulse control can make a noticeable difference within a few weeks.