Updated on September 7, 2026. Disease maps, county lists, and carcass rules move. Confirm the current bulletin on your state wildlife agency page before you eat an animal or haul a whole carcass across a line.
Most “sick deer” calls are not CWD. A skinny, drooling, oddly tame deer in January is the CWD picture. A pile of dead deer in a farm pond in August is hemorrhagic disease. Hairless patches in March are often mange. Ticks on a healthy deer are ecology, not Lyme in the deer. This page is the index. The how-tos stay on their own URLs.
Parent hub: deer safety. Species context: white-tailed deer. If the animal is in the road, that is what to do if you hit a deer, not a disease page.
Facts (sourced)
| What | Number / rule | Source |
|---|---|---|
| CWD in North America | Detected in 37 U.S. states and five Canadian provinces (free-ranging and/or captive cervids), as of June 2026. Also Norway, Sweden, Finland; captive cases in South Korea. | USGS National Wildlife Health Center, June 30, 2026 |
| Human CWD cases | None reported. CDC still treats eating positive meat as a theoretical risk and says to test before you eat. | CDC, Jan. 21, 2026 |
| Who eats venison | CDC survey: nearly 1 in 5 U.S. residents had hunted deer or elk; more than 6 in 10 had eaten venison or elk meat. | CDC |
| 2025 hemorrhagic disease | SCWDS tested 525 wild-ruminant samples from 23 states. 294 were PCR-positive for EHDV and/or BTV. EHDV-2 in 168 white-tailed deer from 16 states. Earliest 2025 isolate: Erie County, Pennsylvania, July 24. | SCWDS Briefs, Winter 2026 |
| Ohio 2025 HD reports | Ohio DNR reported 9,243 dead or sick deer by early November 2025 — the loudest single-state count of that outbreak. | National Deer Association, 2026 Deer Report |
| Michigan bovine TB, 2025 harvest | 4,177 deer tested in the TB area through March 19, 2026; 18 positives (Alpena 5, Alcona 4, Oscoda 4, Montmorency 3, Crawford 1, Presque Isle 1). | Michigan DNR 2025 bTB testing |
| Cooking and CWD | Normal cooking does not destroy prions. A “no prions detected” lab result is not a food-safety certificate. | Virginia DWR, Human Health and CWD |
Last checked September 7, 2026. USGS county/unit shapefiles: doi.org/10.5066/P9HQKKFO (ver. 4.0, August 2026). CDC’s where CWD occurs page, dated May 18, 2026, also says 37 states.
What you are probably looking at
Do not diagnose a deer from a Facebook photo. Use this as a triage, then open the child page or call the agency.
| What you see | Season / place | Most likely | Go here, not this hub |
|---|---|---|---|
| Skinny, stumbling, drooling, no fear of people | Any month; more obvious in late winter. CWD counties. | CWD if you are in a positive unit. Could also be brain abscess, vehicle trauma, or late-stage EHD. | CWD symptoms |
| Dead deer in creeks, ponds, or farm tanks; swollen head or tongue | Late July–first hard frost. Worse after a hot, dry summer. | EHD or bluetongue. Midges, not deer-to-deer. | EHD in deer and blue tongue (BTV) |
| Patchy hair, raw skin, looking “moth-eaten” | Winter–spring. Any region. | Demodectic mange, or Pacific Northwest hair-loss syndrome on blacktails. | mange on deer |
| Lumpy skin, dark “warts” | Year-round. More on bucks. | Cutaneous fibromas. Ugly, usually not fatal. | This page, fibroma section. Meat is generally fine if the lumps are only skin. |
| Loaded with ticks, still acting normal | Spring and fall. East and Upper Midwest. | Not Lyme in the deer. Deer host adult blacklegged ticks; they do not get Lyme. | do deer get Lyme disease |
| Fawn alone in a yard for hours | May–July. | Not a disease. The doe beds it and leaves. | is this fawn abandoned |
If the deer is on a bumper, stop reading this and follow the collision checklist. State crash odds sit on deer collisions by state.
Chronic wasting disease
CWD is a prion disease of the deer family — whitetails, mule deer, elk, moose, and caribou/reindeer. It is not a virus and not a bacterium. Misfolded proteins force normal brain proteins to misfold. There is no vaccine and no treatment. Once clinical signs start, the animal dies.
USGS’s June 2026 North American map lists free-ranging detections in all 37 positive U.S. states on that table, from Alabama and Georgia to Washington and California, plus the long-endemic West and Midwest. Captive-facility detections sit on a shorter list (Colorado, Idaho, Illinois, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, New York, Ohio, Oklahoma, Pennsylvania, South Dakota, Texas, Utah, West Virginia, Wisconsin). In Canada: free-ranging in Alberta, British Columbia, Manitoba, and Saskatchewan; captive-only in Quebec. I am not going to paste a 3,000-county list here. Open the USGS map, then your state’s CWD page, then hunt.
The search phrase “zombie deer” is the same disease. That language lives on what is zombie deer disease. Field signs — wasting, excessive thirst and urination, drool, a blank stare, no flight response — live on CWD deer symptoms. You cannot see CWD in a steak. That is what CWD looks like in deer meat.
CDC’s current hunter advice, in order: do not shoot or eat a sick-looking animal; wear gloves to field-dress; keep kitchen knives out of the gut pile; skip brain, spinal cord, eyes, spleen, tonsils, and lymph nodes; strongly consider a test before you eat; if the test is positive, do not eat the meat. Processing each deer individually matters because CWD prions can contaminate steel and plastic. A 2025 Emerging Infectious Diseases paper showed that equipment used on a positive carcass can seed negative meat, and that Virkon-S or bleach with enough contact time can decontaminate nonporous surfaces. Cooking will not save you. Mechanics of the sample: how to get your deer tested for CWD. Field work around the carcass: how to field-dress a deer and after the shot.
State carcass rules are the trip-breaker, not this paragraph. Wisconsin, Tennessee west of the river, Arkansas’s CWD zone, and Michigan’s positive counties all restrict whole-carcass movement. Read the DNR page for the county you are standing in. Michigan’s statewide hunt context is on Michigan deer hunting.
EHD and bluetongue — the August creek pile
Hemorrhagic disease is the most important viral disease of wild white-tailed deer in the United States. Two related orbiviruses do it: epizootic hemorrhagic disease virus (EHDV) and bluetongue virus (BTV). Biting midges in the genus Culicoides move both. Deer do not give it to each other, and you do not catch it from a carcass or a midge bite.
That is why the classic picture is a dead deer in water. They run a fever, look for a creek, and die there. A hard frost knocks the midges down and the outbreak stops, usually within two weeks. Southern Coastal Plain and Texas herds see the viruses most years and often shrug them off. Northern herds see them less often and die in piles when they do. SCWDS has run the national HD questionnaire since 1982; every state wildlife agency participates.
2025 was a real year. SCWDS’s winter 2026 write-up: 525 wild-ruminant samples from 23 states, 490 of them white-tailed deer. 294 animals PCR-positive. Virus isolated from 136 of those. All three established U.S. EHDV serotypes showed up (1, 2, and 6). EHDV-2 led, including Alabama, Arkansas, Florida, Georgia, Indiana, Kentucky, Maryland, Michigan, Missouri, Mississippi, Montana, North Dakota, Oklahoma, Pennsylvania, Tennessee, and West Virginia. EHDV-6 led in Georgia, Indiana, Maryland, and parts of Kentucky. NDA’s 2026 Deer Report put confirmed HD in at least 27 states and quoted Ohio’s 9,243 dead-or-sick reports by early November. Michigan DNR listed 2025 EHD counties as Berrien, Calhoun, Cass, Clinton, Eaton, Gratiot, Hillsdale, Ingham, Ionia, Jackson, Lenawee, Livingston, Mecosta, Saginaw, Van Buren, and Washtenaw — southern Lower Peninsula, not the Ottawa snow. Idaho Fish and Game confirmed EHD in the Clearwater and both viruses in the Panhandle after a hot, dry summer.
I do not have a 2026 national HD tally yet. If you are reading this in September and finding bloated deer in a ditch, call the agency, do not assume CWD, and do not eat a fevered carcass. The EHD child is EHD in deer. The look-alike virus is blue tongue (BTV) in deer.
Bovine tuberculosis — a Michigan problem, not a national one
Bovine TB (Mycobacterium bovis) is the disease most U.S. deer pages oversell. It is real. It is also geographically tight. Free-ranging white-tailed deer in the northeastern Lower Peninsula of Michigan are the wildlife reservoir that still infects cattle. MDARD’s Modified Accredited Zone is four counties: Alcona, Alpena, Montmorency, and Oscoda. The rest of Michigan is Accredited Free, with extra movement rules in some neighbors.
Hunters are the surveillance. For the 2025 season DNR asked for heads from Alcona, Alpena, Cheboygan, Crawford, Iosco, Montmorency, Ogemaw, Oscoda, Otsego, Presque Isle, and Roscommon. Results posted March 19, 2026: 4,177 deer tested in that TB area, 18 positives. Alpena 5, Alcona 4, Oscoda 4, Montmorency 3, Crawford 1, Presque Isle 1. Zero in Cheboygan, Iosco, Ogemaw, Otsego, and Roscommon in that table. Statewide they tested another 1,199 deer. 2026 focused-collection counties add Charlevoix. Do not pull lymph nodes yourself in those bTB counties — DNR wants the whole head because of the dual CWD/TB risk.
Cattle keep finding it because deer and cows share feed. MDARD announced TB-positive herds in Alpena and Presque Isle in April 2026, then an Iosco County herd on May 6, 2026 — the first infected cattle herd in that county. People can get M. bovis. It is rare in hunters who wear gloves and cook meat through. Lesions look like tan or yellow lumps in the chest cavity or lymph nodes. If you open a deer and the lungs look wrong, bag the carcass, wash up, and call DNR. Official pages: Michigan DNR bovine TB and MDARD bovine TB.
Cattle disease more broadly — not a deer-hunt problem — is on common cattle diseases.
Mange, ticks, and Lyme — three different conversations
Mange on deer is usually demodectic mites, not the sarcoptic mange that wrecks coyotes. Hair falls out in patches. The animal can look awful and still be otherwise healthy, or it can crash in a hard winter. Treatment of free-ranging deer is not a thing you do from the truck. Details, including hair-loss syndrome on Pacific blacktails: mange on deer.
Ticks are not a deer disease. Adult blacklegged ticks (Ixodes scapularis) feed on deer. The Lyme bacterium, Borrelia burgdorferi, does not make deer sick, and deer are not competent reservoirs that infect new ticks the way white-footed mice are. That is why “kill all the deer, kill Lyme” is a bad slogan and a worse management plan. Ecology: deer and ticks. The human question: do deer get Lyme disease. Permethrin on clothes is the hunter fix, not a pill for the deer.
The rest of the list, without padding
Cutaneous fibromas (deer warts)
A papillomavirus. Bucks pick it up on antlers and rubs; biting insects can move it too. The lumps are skin. A few golf-ball fibromas do not ruin the meat. A face so covered the deer cannot see or eat is a different animal — leave it, and call the agency if it is in a backyard. Do not confuse fibromas with the swollen head of EHD.
Brain abscesses
Common in adult bucks, rare in does. Bacteria — often Trueperella pyogenes — enter through the pedicle or a head wound during the rut. SCWDS’s spring 2026 case highlight was a January buck circling with one ear dropped, standing in the same timber for days. That looks like CWD from the road. It is not. You cannot tell without a necropsy. Do not eat a circling deer.
Adenovirus hemorrhagic disease
First tied to California mule deer in 1993–94. Fawns die fast (a few days); adults often live. Drool, open-mouth breathing, ulcers in the mouth. Direct contact and possibly aerosol, not midges. If your agency says AHD, believe them. Do not swap the label onto an August pond die-off that is EHD.
Meningeal worm
Parelaphostrongylus tenuis lives in white-tailed deer with little fuss. In moose, elk, caribou, and some livestock it is a neurological killer. That is a moose and mixed-range problem, not a reason to skip a healthy Michigan whitetail. Gastropods (snails and slugs) are the middle host.
Brucellosis — not a “common deer disease”
The old version of this page called brucellosis common in deer. That oversells it. Brucella abortus in North America is a Greater Yellowstone story: elk, bison, and cattle. White-tailed deer are not the reservoir. Hunters in that ecosystem still glove up around reproductive tissue. Humans get undulant fever from livestock more often than from a Midwestern buck. Do not import that risk onto an Ohio EHD deer.
New World screwworm, 2026
This is the one that was supposed to stay south of a sterile-fly barrier. USDA APHIS confirmed the first U.S. animal case of the current outbreak on June 3, 2026, in a calf in Zavala County, Texas — first Texas case since 1966. Larvae eat living tissue. As of August 31, 2026, the Texas Animal Health Commission listed 16 Texas counties and 38 premises with cases, and movement restrictions in parts of Bandera, Brewster, Crockett, Edwards, Jim Hogg, Medina, Pecos, Presidio, Schleicher, Starr, Sutton, Terrell, Uvalde, Val Verde, and Zapata. USDA launched a screwworm wildlife page for hunters on September 1, 2026. I am not going to invent a wild-deer case count I have not seen. If you find maggots in a fresh wound on a Texas deer, livestock, or pet, report it: TAHC 1-800-550-8242 for livestock, Texas Parks and Wildlife for wildlife. Dashboard: APHIS current status.
What to do with a sick or dead deer
- Do not shoot it for the cooler. CDC and every state I read agree: leave the obviously sick animal. If you already shot a deer that then looked wrong, still test it and do not eat it pending results.
- Do not drag a mystery carcass home to “figure it out.” Photograph from a distance, mark a GPS pin, call the wildlife agency. Many states want EHD and CWD reports in a web form, not a trunk.
- Gloves, then field-dress. CDC: latex or rubber gloves; keep brain and spine out of the meat; do not use kitchen knives. Bone it out in CWD country. How-to: field-dress a deer.
- Test where the map is red. Drop the head or lymph-node kit where your state tells you. Timeline and “not detected” vs “safe”: get your deer tested for CWD.
- Label the packages. If one deer in a pile of freezer paper tests positive, you need to know which one. Virginia DWR says so out loud.
- A backyard fawn is almost never this list. What to do if you find a fawn.
Shot placement still matters more than most disease lectures. A gut-shot deer you lose is a wasted animal and a night of tracking, disease or not: shot placement chart.
FAQ
Can humans get CWD from deer meat?
No confirmed human case. CDC has said that in public since this page first went up, and it said it again on January 21, 2026. Monkey studies and the mad-cow precedent are why they still tell you to test and to skip positive meat. Cooking does not kill prions. Full hunter steps are on testing and meat.
Is a dead deer in a pond CWD?
Usually no. That is the EHD/BTV picture in late summer. CWD deer more often look thin and unafraid in winter. Confirm with the agency. Child pages: EHD, CWD symptoms.
Do deer give people Lyme disease?
No. Deer do not get Lyme and they do not infect ticks with Borrelia the way mice do. They do carry the adult ticks that bite you in November. Do deer get Lyme disease.
Should I eat a deer with warts?
If the lumps are cutaneous fibromas and the animal was otherwise healthy, trim the skin and cook the meat. If the deer was skinny, circling, or fevered, skip it and test. When in doubt, do not eat it.
Where do I report a sick deer?
Your state wildlife agency, not this website. Michigan: DNR sick-deer form. New York: DEC EHD report. Texas wildlife screwworm: TPWD. For a crash, police first — hit-a-deer checklist.
Sources
- USGS NWHC, Expanding distribution of CWD (June 30, 2026 map; 37 states / five provinces)
- Richards, B.J., USGS CWD distribution by state and county, ver. 4.0, August 2026
- CDC, About CWD (Jan. 21, 2026)
- CDC, Where CWD occurs (May 18, 2026)
- CDC EID, Detection and decontamination of CWD prions during venison processing, April 2025
- SCWDS Briefs Vol. 43 No. 4, 2025 hemorrhagic disease update
- National Deer Association, 2026 Deer Report
- Michigan DNR, EHD
- Michigan DNR, bovine tuberculosis
- MDARD, Iosco County cattle herd, May 6, 2026
- Virginia DWR, Human health and CWD
- USDA APHIS, first 2026 U.S. screwworm detection, June 3, 2026
- Texas Animal Health Commission, New World screwworm (checked Aug. 31, 2026 posting)
- New York DEC, EHD
Related wildlife disease pages stay live: squirrel diseases, cattle diseases. Diet, not pathology: what do deer eat. Species index: deer species.
