SHERIDAN — As hunt areas around the region open this month, the Wyoming Game and Fish Department Sheridan Regional Office is asking hunters who harvest elk in the Bighorn Mountains to help with brucellosis surveillance. Blood samples should be collected immediately after harvest and submitted to a regional WGFD office, a hunter check station or by mail within one or two days of harvest.
Five thousand brucellosis testing kits were mailed to hunters with limited quota licenses in the Bighorn Mountain region. Since the disease is spread by cow elk (females), hunters with cow tags were more likely to receive a kit than hunters with antler-only or a general elk license,
Game and Fish Wildlife Disease Specialist Hank Edwards said. Game and Fish regional offices and personnel also have kits available for hunters who did not receive one but wish to participate in voluntary brucellosis testing.
Statewide, 10,000 brucellosis testing kits were sent to hunters. The concentrated surveillance effort in the Bighorn Mountains is the result of two elk, a cow and a bull, harvested on Bald Mountain last year testing seropositive for brucellosis.
A seropositive test result indicates that antibodies for brucella abortus bacteria were found in their blood, meaning the elk were exposed to brucellosis at some point but not necessarily infected with the disease, District Wildlife Biologist Tim Thomas said.
“It’s all epidemiology right now. We’re just trying to figure out how they got here,” Edwards said. “We don’t know if they were resident elk or migratory.”
While Edwards cautioned against “putting the cart too far before the horse” and prematurely implying there is brucellosis in the area, he said it is important to determine if brucellosis has become an issue in the Bighorn Mountains because it has been confined to elk, bison and some cattle in a Designated Surveillance Area that covers a portion of northwest Wyoming and parts of Montana and Idaho since the late ‘90s.
In fact, the Greater Yellowstone Area is the only area in the United States with confirmed cases of brucellosis in elk, bison and cattle. Cattle from the Designated Surveillance Area are subject to strict monitoring and testing before they can be sold or shipped out of state, Edwards said.
“This is the first time we’ve seen elk test positive for brucellosis this far east from Yellowstone,” Thomas said.
Edwards and State Wildlife Veterinarian Mary Wood are in Sheridan to continue training Game and Fish employees on how to collect tissues from harvested elk that will be cultured for brucellosis. The department’s wildlife disease lab in the Wyoming State Veterinary Lab will conduct four to six tests on collected blood samples to look for antibodies to brucella abortus bacteria. If the blood from an elk tests seropositive for brucellosis, the tissues from that elk will be cultured to see if it was actually infected with the disease.
The tissues WGFD personnel will collect are the supramammary and the iliac, which are both lymph nodes associated with a cow elk’s reproductive tract.
Research has shown that brucellosis “hides” in those two reproductive lymph nodes until a cow elk reaches its third trimester of pregnancy sometime in February or March, Wood said. At that time, the disease emerges and migrates towards the fetus. Elk that are infected with brucellosis typically abort their first calf and carry subsequent calves full-term.
Brucellosis is spread when female elk or bison abort their calves or expel the bacteria during the birthing process and wildlife or livestock have “muzzle contact” with the fetus or the area immediately surrounding the birthing area through sniffing or licking.
Wood stressed that hunters do not need to be concerned about contracting brucellosis from their elk since they harvest in the first and second trimester of pregnancy and the disease does not manifest until the third trimester.
“We have sampled the Bighorns in the past and not found brucellosis. So far, there is good evidence to say it is not established here,” Edwards said.
Still, it is a highly contagious disease and could affect cattle in the area if it is present, and that is why the Game and Fish Department is urging hunters to participate in brucellosis surveillance through the end of the hunting season in November.
The U.S. has spent billions of dollars to eradicate brucellosis in cattle and humans since the 1930s, primarily through milk pasteurization and cattle vaccination, Thomas said. Brucellosis is still common in third-world countries in animals and humans, in whom it can cause fevers and joint and muscle pain and is considered a chronic disease.
Tips for collecting usable blood samples
SHERIDAN — The Wyoming Game and Fish Department mailed 5,000 brucellosis testing kits to hunters with licenses in the Bighorn Mountains. Hunters who harvest an elk, particularly a cow elk, are asked to collect a blood sample to assist the department with brucellosis surveillance. Here are a few tips for collecting a usable blood sample, according to a Game and Fish Department media release:
• Carry your kit with you in the field and collect the blood sample as soon as possible.
• Collect blood from the neck, heart or chest cavity.
• Keep the blood sample cool. Do not freeze it.
• Fill out the data section on the instruction sheet with specifics about the location and major drainage of your harvest.
• Use the postage-paid mailer and drop your sample in the nearest post office box, give it to hunter check station personnel or deliver it to the Cody or Sheridan regional offices.
• Time is of the essence. Ship the sample in one to two days to prevent spoilage.