Testing for CWD


Brucellosis is a bacterial disease primarily of Rocky Mountain elk and bison. The disease often causes cows to abort their first fetus after becoming infected. It can also infect domestic cattle, but an eradication program has almost eliminated the disease in cattle.


What is brucellosis?

Brucellosis is a bacterial disease that is limited in distribution to northwestern Wyoming and adjoining portions of Idaho and Montana. It primarily affects elk and bison. After becoming infected, cows will usually abort their next pregnancy, and will sometimes have abortions in subsequent pregnancies. Brucellosis also infects domestic cattle, but a state and federal eradication program almost eliminated the disease in cattle.

A gloved lab employee holds a mailed box containing a brucellosis sample

2023 Brucellosis Focus Areas

In the northwestern part of the state where brucellosis is found, the Wyoming Game and Fish Department conducts annual surveillance to monitor prevalence of the disease. Hunters who draw elk tags in a designated surveillance area are shipped brucellosis test kits, used to draw blood samples from harvested animals. Additional surveillance areas are selected annually to evaluate possible spread of the disease.

Elk bugle

How does brucellosis affect me?

Humans can be infected with brucellosis. Symptoms in humans include recurring low-grade fever, joint or back aches, night sweats, and depression. Such symptoms can occur weeks or months after exposure. Symptoms can be treated with a prolonged course of antibiotics. To avoid contracting brucellosis, hunters should always wear protective gloves when field dressing. Reproductive organs, placentae, or swollen testes or joints should not be opened.

How to take a blood sample for brucellosis testing

A group of five black cows standing side by side

Impacts on wildlife populations and cattle operations

The prevalence of brucellosis can be quite high (up to 75% in bison), yet there is no evidence that brucellosis has noticeable impacts on populations. The primary management concern is the possible transmission of brucellosis from elk or bison to domestic cattle. States with infected cattle herds suffer economic hardships. The threat to cattle results in ongoing friction among wildlife management agencies, ranchers, and federal agencies.

Elk hunter

Brucellosis Raffle

Each year, the Wyoming Game and Fish Department offers a hunting gear raffle for hunters who submit samples from their harvested game for brucellosis testing. This raffle is our way of incentivizing hunters to submit samples and thank those who do. Hunters play a critical role in our ability to monitor brucellosis in Wyoming, and we are grateful for those who partake in this effort.


Hunters will be entered to win prizes if they provide a usable brucellosis sample(s), with complete and accurate hunter and harvest information. Winners will be drawn randomly by early March each year and will be notified directly. 

2023 Raffle Prizes

Thank you to our raffle sponsors: Benelli, Vortex Optics, Sig Sauer, and Maven. Hunters who successfully draw multiple tags and receive multiple test kits will be entered into the raffle for each usable sample returned. Winners will be drawn in March.

Grand Prize Package

Benelli Lupo Rifle (Caliber winner's choice, donated by Benelli), Vortex Strike Eagle 3-18x44 FFP Rifle Scope (donated by Vortex Optics)

2nd Place

Sig Sauer Oscar8 27-55x80 Spotting Scope (donated by Sig Sauer)

3rd Place

Maven C1 10x42 Binoculars (donated by Maven)

Additional Prizes

Game and Fish sweatshirts (donated by the Wyoming Game and Fish Department)

Non-feedground elk brucellosis surveillance reports

Bighorn Mountains Elk Movement and Brucellosis Study

After eleven sero-positive elk were found in the Bighorn Mountains from 2012 - 2016, an elk movement study was initiated. The study used GPS collars to track movement and interactions of elk herds. These data were used to determine possible routes of brucellosis transmission, identify calving areas, and model how brucellosis may spread in the future. The study was accompanied by increased brucellosis surveillance testing of hunter-harvested elk. The study concluded after 2021, and reports for the study are available through the dropdown menu below.