Montana Fish, Wildlife, and Parks expands on Bovine Tuberculosis

Publisher's Note: The following is a part of a press release sent to the Phillips County News in regards to Bovine Tuberculosis. Earlier this year, during the hunting season, Montana FWP sent a release stating that Bovine TB had been found. That release was run in the November 17 issue of the Phillips County News. When Montana FWP sent the following information, we did not have room for it.

This info is to assist hunters in efforts to detect the disease, but due to hunting season ending on Sunday, November 28, the info will be beneficial to ranchers.

About the disease:

Bovine TB causes lesions inside the lymph nodes, lungs, liver, spleen, and skin of affected animals. Livestock rarely show any clinical signs of disease, but the disease can cause significant negative economic impacts on the livestock industry due to quarantine and testing requirements associated with disease investigations.

The disease is primarily spread from animal to animal via respiratory secretions but can also be transmitted by the fecal-oral route or by ingestion of contaminated food. Shared feeding is believed to be the primary transmission pathway between cattle and wildlife, as cattle feed becomes contaminated with infectious saliva, urine, and feces.

There are no documented cases of bTB causing population declines in deer or elk in states where the disease is endemic, but the risk of wildlife serving as a reservoir for further transmission to livestock, other wildlife, or humans remains a concern.

Bovine TB (M. bovis) is not the major cause of human tuberculosis, which is caused by a related bacterium, Mycobacterium tuberculosis, but humans are susceptible to bTB. Humans can be infected by drinking raw milk from infected cattle, inhaling infective droplets from an infected animal, or by contact with infective body fluids via open wounds. Due to a robust meat inspection program and the pasteurization of milk for retail sale, bTB is not a food safety threat. Bovine TB accounts for less than two percent of human tuberculosis cases in the United States.

There has been at least one confirmed case of transmission of bTB to a human from an infected white-tailed deer in the United States. In that case, the hunter was believed to have had an open wound that was exposed to the deer’s bodily fluids during the field dressing process.

Past detection in Montana

Before this most recent detection in livestock, the disease had been detected in some Montana game farms and a few free-ranging wild animals around one of those farms. Bovine TB was detected in at least six game farms in Montana in the early 1990s, including farmed fallow deer detected in Sheridan and Richland counties, and farmed elk in Granite, Park, Bighorn, and Carter counties. Since that time, FWP has tested animals found with lesions similar to those caused by bTB and has opportunistically collected lymph nodes from hunter harvested deer to look for evidence of bTB. The disease has not been detected in wildlife during this sampling effort over the last 20 years.

How can hunters and trappers protect themselves from bTB?

Hunters and trappers should always wear rubber gloves and eye protection when field dressing a harvested animal. Hands and instruments should be washed thoroughly after field dressing is completed. Hunters and trappers should not harvest animals that look sick, and should report any animal that appears sick during field dressing to FWP.

What is FWP doing about bTB?

FWP already performs examinations and testing of animal carcasses that are suspected of being diseased. FWP also collects lymph nodes for routine bTB testing from deer harvested in areas with past bTB detections. FWP is increasing its efforts to look for bTB in deer by collecting tissue samples for both CWD and bTB surveillance in the target area. FWP will be testing other small mammals in the area as well such as coyotes and raccoons.

What can you do to help?

Samples from a large number of animals are needed for a sufficient survey effort in wildlife. Whenever possible, samples will be collected from hunter-harvested animals. Please help with this wildlife surveillance effort by providing lymph nodes from your deer or pronghorn antelope if it’s harvested within the surveillance area (see map) during the rest of this hunting season.

Also, while most game animals are healthy, if you do notice abscessed lymph nodes, abscesses in the lungs or abscesses inside the chest cavity during field dressing, please report those findings to FWP. Animals can be sampled at locations where CWD sampling is already being conducted.

To learn more

Please see the attached FAQs about bTB and learn more about the disease. For more information about bTB in humans, visit https://www.cdc.gov/tb/publications/factsheets/general/mbovis.pdf.

FOR MORE INFORMATION:

Montana Department of Livestock

Dr. Tahnee Szymanski, Assistant State Veterinarian, (406) 444-5214, [email protected]

Montana Fish Wildlife and Parks

Dr. Jennifer Ramsey, Wildlife Veterinarian, (406) 577-7880, [email protected]