Prepared by Amy Keith

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Bovine Tuberculosis

• Prepared by Amy Keith
• Designed for Michigan Farmers Hunters

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3 Types of Tuberculosis (TB)

• Human TB
• Rarely transmitted to non-humans
• Avian TB
• Typically restricted to birds
• Bovine TB
• Most infectious form, capable of infecting most
  mammals

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Bovine TB Objectives

• Natural History
• Distribution
• Transmission
• Diagnosis
• Human Implications
• Conservation Implications
• Elimination in Michigan

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Natural History

• Agent bacteria, Mycobacterium bovis
• Prior to 1994
• Fairly common in U.S. cattle
• Only 8 known cases in U.S. wild deer
• Since 1994
• Near eradication in U.S. cattle
• Many other mammals testing positive

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Distribution

• Widespread
• Spreads rapidly
• Growing number of cases
• Common in Michigan
• Diversity of Mammals

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Distribution (cont.)

• Diversity of Mammals
• Cattle
• Deer (wild captive)
• Coyotes
• Raccoons
• Bobcat
• Bear
• Etc.

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Deer Management Unit 452
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Michigan DNR Surveillance
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Percent of TB-Positive Deer

• 1995 4.46
• 1996 1.13
• 1997 1.20
• 1998 0.86
• 1999 0.30
• 2000 0.20
• 2001 0.25

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Transmission

• Direct Contact
• Cattle
• Airborne
• Contaminated water,
• feed, milk
• Close contact
• Wild Deer
• Airborne
• Close contact

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Transmission (cont.)

• Indirect Contact
• Cattle Wild Deer
• Airborne
• Cattle ? Deer
• Deer ? Cattle

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Diagnosis

• Chronic
• Contagious, Infectious
• Progressive
• Can be very slow
• Sometimes only apparent
• in advanced stages
• Sometimes remains
• dormant throughout life

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Diagnosis (cont.)

• Behavioral Changes
• Weakness
• Loss of appetite
• Weight-loss
• Fluctuating fever
• Eventual hacking cough

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Diagnosis (cont.)

• Post-mortem detection
• Enlarged lesions in lymph nodes / lungs
• Tan / yellow lumps on inside of rib cage

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Human Implications

• Could Bovine TB spread to humans?
• Yes, however it is extremely unlikely!
• Slightly at risk
• Owners / handlers of cattle
• Very slightly at risk
• Field-dressing deer
• Eating cooked beef / venison

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Conservation Implications

• Michigans Wildlife
• White-tailed deer herd other mammals at risk
• Social risk
• Ecological risk
• Economic risk

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Conservation Implications (cont.)

• Michigans Livestock Industry
• Cattle
• Severe economic risk
• Michigan no longer
• Bovine TB-Free

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Elimination in Michigan

• Cattle
• Early 1900s Testing on farms, monitoring
  slaughter houses
• 1979 All Michigan cattle declared Bovine
  TB-free
• 2000 Status downgraded to Non-Modified
  Accredited
• Raised concern in cattle with Michigan deer
  testing positive

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Elimination in Michigan (cont.)

• Wild Deer
• Hunters voluntarily submit heads for examination
• Mandatory feeding ban
• DNR optimistic about future elimination
• DNR provide management strategies

No Feeding!
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DNR Management Strategies

• Ban feeding baiting of deer elk
• Reduce population of deer
• Reduce the average age of deer population
• Reduce face-to-face contacts between animals
• Ban new captive deer / elk enclosures

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Vaccination / Medication

• Currently, neither vaccinations nor medications
  are available for cattle or deer

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References

• Michigan Department of Natural Resources
• www.bovinetb.com
• Web Health Center
• www.webhealthcenter.com
• U.S. Department of Agriculture
• www.fsis.usda.gov
• Cattle Pictures
• www.lkcattle.com

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DNR Bovine TB Surveillance