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Bovine Tuberculosis (bTB)

Bovine tuberculosis (bTB) is a chronic disease caused by the bacterium Mycobacterium bovis. Bovine TB primarily affects cattle; however, other animals may become infected. Bovine TB is spread through animal to animal contact with infected respiratory secretions or through direct ingestion of the bacteria.

Each year DNR staff collect tissue samples from wild deer (hunter-harvested or reported sick/dead) for bTB testing.  Samples are collected from across the state to monitor the presence of bTB in Indiana. To date bTB has not been detected in Indiana’s wild deer population.

Contents

History of bTB surveillance

Indiana DNR and other State and federal partners test wild white-tailed deer for bTB because it was found in Franklin County cattle in 2008, 2009, and 2016, and in Dearborn County cattle in 2011. The disease was also detected in captive deer from a farm in Franklin County in 2009. Between 2009 and early 2017, 3,524 wild, hunter-harvested white-tailed deer were sampled in the bTB surveillance zones. None of these deer tested positive for the disease.

In December 2016, another case of bTB was detected in a different cattle farm in Franklin County. As a result, surveillance in the 2017-18 deer hunting season was focused in a 225-mile2 area centered on this farm in Franklin and Fayette counties.

Just prior to the 2017-18 hunting season, U.S. Department of Agriculture, Animal and Plant Health Inspection Service (USDA-APHIS) Wildlife Services collected 37 raccoons, 16 deer, and 12 opossums from or adjacent to the affected premises to test for bTB. One wild raccoon from the December 2016 farm tested positive for bTB. Similar to the positive deer and raccoon that were collected from the Franklin County farm during 2016, genetic analysis of the mycobacterial organism cultured from this more recent raccoon strongly suggested that the infection was transmitted from cattle to wildlife.

During the 2017-18 hunting season, hunters brought in 531 deer to the various check stations, 480 (90%) of which were collected from within the bTB surveillance zone. These deer consisted of 65 male and female fawns, 104 male and female yearlings, 141 females that were 2 years of age or older, and 169 males that were 2 years of age or older. Bovine tuberculosis was not detected in any of these deer.

During the 2018-19 hunting season, the bTB surveillance area was reduced to a 1.5-mile radius centered on the affected farm, although deer could still be submitted from within the 225 square mile area if hunters were concerned about bTB. Hunters submitted samples at a single check station on weekends or at a partnering deer processor. Indiana DNR tested 92 deer. Bovine tuberculosis was not detected in any deer tested during the season.

In 2019, as part of a targeted clean-up effort after infected cattle were removed from the area, 95 additional deer and 34 small mammals were removed within a 1.5-mile radius of the affected farm. Bovine tuberculosis was not detected in any of these deer; however, bTB was detected in one raccoon taken from the affected farm.

Inspect harvested deer

While field dressing your deer, look for white, pearl-like sores (lesions) on internal organs or inside of the carcass. In the unlikely event you see lesions, exercise caution in handling the animal.

Do not proceed with further processing of the carcass before contacting the Indiana State Board of Animal Health (BOAH) to speak to a staff veterinarian. Refrigerate (or ice down) the carcass if possible.

Keep the animal, including the head, intact until examined. Taking digital photos of the unusual lesions or organs that can be texted or emailed, upon request, can be helpful to determining the status of animal.

To contact a BOAH veterinarian, call 1-877-747-3038 (toll free). This number is answered Monday-Friday, 8 a.m. to 4 p.m. Messages left on weekends or holidays will be returned as soon as possible. A veterinarian will advise you, free-of-charge, about the appropriate use of the animal and may collect tissue samples for further testing.

By reporting any suspicious lesion, you are helping to protect the health status of Indiana’s white-tailed deer resource.

If BOAH or DNR collect the carcass for further testing, the DNR will note that the deer that was harvested was taken for testing and your existing license can be used for the harvest of another deer. (The BOAH veterinarian will refer you to DNR; DNR staff have access to the harvest reporting and hunting license systems.)

Wash hands

After field dressing or handling any carcass or other raw meat, wash your hands with soap and water. Hand washing removes disease-causing bacteria, including tuberculosis. This practice should always be followed, even if the animal appears healthy.

2020 current bTB surveillance

To date, bTB has not been detected in any of the hunter-harvested deer sampled within the Franklin County surveillance zone. These results suggest that the prevalence of bTB in wild deer within the Franklin County surveillance zone has remained at levels that are difficult to detect and is likely very low to non-existent. As a result, the Indiana DNR will not conduct intensive bTB surveillance in Fayette and Franklin counties during the 2020-21 deer hunting season. However, Indiana DNR will still conduct targeted surveillance of deer if they are reported to be exhibiting signs of bTB and recommends that hunters continue to inspect the chest cavity of harvested deer for lesions. If lesions are found, hunters should contact an Indiana State Board of Animal Health veterinarian by calling 877-747-3038 or visit boah.IN.gov.

FAQs about bTB

What are the signs of bTB?

TB is a chronic and progressive disease that can cause gradual debilitation and emaciation, coughing, nasal discharge, and difficulty breathing.  Small lesions or abscesses may be visible inside the chest cavity, covering the lungs, liver, and ribcage in late developed individuals.  Many individuals in the early stages of TB may not have any symptoms.

How does bTB occur?

TB is spread through the respiratory secretions between infected and uninfected individuals.  Transmission typically is more common when animals are in close proximity to one another.  Studies have shown that TB can exist in the environment for 18-332 days in 54-75 F temperatures, however, it is difficult to isolate TB from pastures where infected animals have grazed.

What happens when a deer is submitted for bTB testing?

The lymph nodes in the neck and head are removed and submitted to two different laboratories for testing. Samples are sent to the Animal Disease Diagnostic Laboratory (ADDL) at Purdue University where they are examined microscopically for infection with bTB bacteria.

The samples are also submitted to the National Veterinary Services Lab (NVSL) for a more conclusive test known as a culture. Culturing is the most reliable way to test for bTB and increases confidence in the overall surveillance effort. If bTB bacteria are present, the cultured samples will grow the bacteria under controlled conditions. However, because bTB bacteria grow very slowly, test results may take three to four months to complete. The results from the culture test will be posted online as soon as they are available.

Hunters may view results for a submitted deer. If the result is positive, DNR will contact the hunter who submitted the deer.

Will I be notified of my deer’s bTB test results?  

Yes. Hunters can view their test results by clicking on the link “View bTB test results” at the top of this webpage. The deer’s confirmation number is needed to check results. Final test results may take eight to 12 weeks to appear online.

Am I required to turn over a sample of my deer?

No. Participation in bTB monitoring program is optional.

How can I tell if the deer I harvested has bTB?

One cannot determine if an animal has bTB from appearance alone.  Confirmation of infection must be through laboratory testing of animal tissue. DNR officials recommend that hunters not process or consume any deer that is obviously ill or emaciated.

What if a deer tests positive for bTB?

Indiana DNR has established a response plan if a wild white-tailed deer tests positive for bTB. The response will depend on the sex and age of the infected animal and the genetics of the bTB bacteria found in that deer.

  • If a single buck tests positive for bTB and the genetics of the bTB indicate that the deer was infected from a bTB-positive farm prior to 2015:
    • If a single buck tests positive for bTB and the genetics of the bTB indicate that the deer was infected from a bTB-positive farm prior to 2015:
    • DNR will determine the precise location where the deer was harvested.
    • No additional deer will be removed for control purposes.
    • Surveillance efforts will increase the next year, centered on that location.
  • If a single doe or fawn tests positive for bTB OR if a single buck tests positive for bTB, AND the genetic strain of the bTB indicates that the deer was infected from any known positive bTB farms (2016 or later):
    • DNR will determine the precise location where the deer was harvested.
    • Biologists will identify the maternal and/or buck groups that use the area where the infected deer was harvested.
    • Maternal and/or buck groups whose home ranges overlap with the identified area will be removed. A group of deer may consist of eight to 25 deer.
    • Surveillance efforts will increase the next year, centered on that location.

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