Michigan’s deer herd faces several diseases that can affect hunter harvests, meat safety, and long-term population health. Here’s a streamlined guide to the conditions you’re most likely to encounter in the woods or on trail cameras.
Lumpy Jaw, Food Impactions & Arterial Worms
A swollen jaw—often called “lumpy jaw”—is usually caused by a bacterial infection of the jawbone (Fusobacterium necrophorum, Actinomyces bovis). These infections create hard lumps filled with pus and can make chewing painful.
Another cause is arterial worms (Elaeophora schneideri). These worms block blood flow to jaw muscles, causing food to pack into the cheek and creating a large lump.
For hunters:
- Deer often survive for long periods with these conditions.
- The meat is typically safe if the infection is confined to the head, but many hunters choose not to consume these deer.
- These conditions are not known to infect humans.
For more information on this visit askifas.edu.
EHD: The Disease Behind Misshapen Hooves
Epizootic Hemorrhagic Disease (EHD) is spread by biting midges and can cause rapid die-offs—up to 90% in local pockets. Michigan has experienced multiple significant outbreaks in recent years.
Surviving deer often show elongated, cracked, or sloughed hooves, which result from fever and vascular damage during infection.
Signs of EHD:
- High fever, drooling
- Swollen head or tongue
- Dead deer found near water
- Hoof deformities months later in survivors
Good news:
EHD does not infect humans, and unaffected meat is safe to eat.
For more information visit michigan.gov and this article on Diseases by The Center for Food Security & Public Health.
CWD: Slow, Fatal, and Long-Term
Chronic Wasting Disease (CWD) is a neurological disease caused by prions—misfolded proteins that destroy the brain. It spreads through saliva, urine, feces, and contaminated environments.
Unlike EHD, CWD doesn’t cause sudden die-offs. Infected deer can look normal for years before showing symptoms:
- Extreme weight loss
- Tremors, drooping head
- Loss of fear, wandering aimlessly
Michigan has confirmed hundreds of cases since 2015.
Safety:
- No proven human cases, but CDC and DNR recommend not eating CWD-positive deer.
- Use gloves when field dressing and avoid cutting into the spine or brain.
- Testing is highly recommended in surveillance areas.
Cutaneous Fibromas (“Deer Warts”)
Cauliflower-like skin tumors caused by papillomavirus.
- Look nasty but rarely affect meat.
- Not transmissible to humans.
Ticks & Lyme Disease
Deer carry blacklegged ticks, which spread Lyme disease to humans.
- Wear permethrin-treated clothes and check for ticks after every hunt.
What Michigan Hunters Should Do
- Don’t consume sick-looking deer.
- Wear gloves when field dressing and butchering.
- Get deer tested for CWD or bTB in affected counties.
- Report sick or multiple dead deer to the DNR, especially near water (EHD clusters).
- Dispose of carcass parts properly—don’t leave spinal columns or heads on the landscape.
