Deer with CWD shed prions in urine, and lure rules differ by state

STEP 1 · Mouse bioassay

Terminal urine concentrated tenfold sickened two of nine mice

Haley and colleagues published the mouse bioassay during 2009 in PLoS ONE. The urine came from five white-tailed deer already terminal with chronic wasting disease. Those deer had been infected at Colorado State University by brain or by blood or by saliva. They pooled the urine and dried it and restored it to 0.1 times the volume collected. In the paper that step is called a 10-fold concentration. The material was injected into brains of mice that make a deer prion protein.

Prion disease developed in two of the nine mice. One mouse reached disease at 370 days and the other at 376 days. A western blot plus a tissue stain showed the abnormal protein in both brains. A third mouse never looked ill and died at 582 days, when cyclic amplification found the protein. The same preparation of saliva from those five deer caused disease in eight of nine mice. The urine itself stayed negative by western blot and by ELISA. Donors showed mild kidney inflammation.

That urine was pooled and concentrated and then injected into mouse brains. No retail bottle was part of the test. The test also did not measure how often one wick would give a wild deer the disease.

STEP 2 · Seeding assays

Urine from deer that carry the infection seeds the prion assay at frequencies that follow genotype and disease stage

Real-time quaking-induced conversion marks a well positive when the sample drives normal prion protein to form amyloid. A positive well does not prove a free-ranging deer would sicken from that volume.

Henderson and colleagues applied the assay to saliva and to urine collected from white-tailed deer that had been exposed to CWD. The Journal of Virology published that paper in 2015.

Shedding of prions was found as soon as 3 months following exposure. The abstract describes shedding that continued for the whole disease course. It estimates thousands of infectious prion doses from one deer across the whole infection.

Using a brain sample with a known lethal dose in cervidized mice, the curve placed the 50 percent lethal dose at 10 milliliters in urine from infected deer and at 1 milliliter in saliva. Mouse-brain injection data fitted to a lab curve do not forecast infection for a deer at a scrape.

Denkers and colleagues reported the longer white-tailed deer work in Emerging Infectious Diseases during 2024. At Colorado State the deer were given low oral doses made from infected brain or from saliva. They were followed for up to 66 months. Iron oxide beads pulled material out before the seeding test.

Seeding hit 9 of 16 samples of urine from deer with glycine on both gene copies at prion-gene codon 96. Seeding hit 1 of 50 samples of urine from deer with serine at codon 96 or with a rare codon 103 change. Urine samples from sham-inoculated deer numbered 28 and every sample stayed negative. Inside the common genotype group 1 of 6 deer produced only negative urine for the full course.

The abstract reports prions in feces or in urine or in saliva as soon as 6 months. The first positive urine sample in the common genotype landed at 18 months. Only 1 of 2 deer tested then was positive.

Feces from the same animals seeded sooner and in a greater portion of samples. Denkers and colleagues cite earlier studies of white-tailed deer as well. Those studies found that infections could begin after a large oral dose of saliva or of urine or of feces.

STEP 3 · Binding tests

Urine from one infected deer stayed on wheat grass after washing

Pritzkow and colleagues left wheat grass roots and wheat grass leaves in urine for a span of 1 hour. The urine came from one white-tailed deer affected by chronic wasting disease. Cell Reports printed the paper in 2015. Serial amplification still found the prion on roots and on leaves after 5 washes. Feces from that deer did too.

A separate feeding test placed hamster scrapie brain on wheat grass. That test did not place deer urine on the plants. All 5 hamsters fed exposed roots developed prion disease and all 5 fed exposed leaves did too. A direct oral brain dose produced a mean incubation of 147 days. Exposed roots produced a mean incubation of 159 days. Exposed leaves produced a mean incubation of 164 days. Standard errors were 10, 10 and 13 days.

Prion was still present at 49 days on those living leaves after a spray of the same hamster brain. The urine trial shows binding to the grass. The hamster trial shows oral infection from scrapie on the grass.

Johnson and colleagues mixed hamster scrapie prion with soil minerals. PLoS Pathogens carried that paper in 2006. The prion bound to montmorillonite clay. Buffer washes did not pull detectable prion off that clay. Clinical scrapie appeared at 93 days after hamsters received the clay-bound prion by brain injection. A control pellet made with no clay had a mean time to illness of 178 days. Animals given clay by itself stayed without symptoms through 200 days. The tubes held hamster scrapie on purified clay only and held neither whitetail urine nor field soil. The bound prion protein stayed infectious.

STEP 4 · State pages

Virginia and Vermont ban natural urine and Pennsylvania lifted its outdoor ban

The Virginia Department of Wildlife Resources bars possessing or using products with natural deer urine or with scent gland secretions or with other bodily fluids. The ban applies while people are taking wildlife or attempting to take it. It also applies while they are attracting wildlife or scouting wildlife. July 1, 2015 is the date that page gives for the body-fluid rule. The department says it cannot halt sales of the products. A bottle may still sit on a store shelf. The page says chronic wasting disease has still shown up in herds that held a low-risk certificate. It says no test offered for sale can declare these products clean before sale.

Vermont Fish and Wildlife put out a release dated September 29, 2026. The release says the state bans any deer lure that uses deer urine or another deer bodily fluid. The release says "CWD has not been detected in Vermont." No testing program lifts the risk and no special certification lifts it either. The release cites no accepted test for a living deer and says infected deer can shed across years before signs show.

A notice from the Pennsylvania Game Commission is dated September 30, 2026. The notice says "the regulatory prohibition on the use of cervid urine-based attractants in any outdoor setting has also been removed." The notice applies to the 2026-27 seasons. A 2025 state law is what the notice credits with making these attractants legal. Commercial trash is still required for high-risk parts after the carcass leaves the kill site. Targeted feeding limits can be set by the executive director for a county or a township. Read the current digest for your unit. That September notice leaves room for a later township feeding order.

Rules vary once you leave Virginia, Vermont and Pennsylvania. Read your state wildlife agency page before the season.

STEP 5 · Home rule

Pack a synthetic scent where natural urine is banned afield

Our read is that infected deer put prions in their urine. How much is present swings widely by deer and also by genotype and disease stage. A bottle produced from captive deer can carry that material well past the distance one wild deer walks.

We keep a captive-facility watch list of captive-facility detections by county. Some of those counties show no wild detection. The watch list names no scent maker and it grades no bottle.

Before opening day, open the current regulation page for each state you plan to hunt. Write the check date and one status. The choices are banned during the hunt, limited to a named zone or still allowed. A banned-during-the-hunt mark means the natural bottle stays home.

Both Virginia and Vermont point people toward synthetic lure. Virginia's statewide ban also takes in urine from a deer you killed yourself. The ban takes in a tarsal gland from that deer on the same terms.

The page after the shot in CWD country covers waste disposal along with transport, sampling and cooling. Dead deer beside water from late summer to the first hard frost fit another disease. EHD or CWD explains that split.