Management of on-farm risk to livestock from bovine tuberculosis in Michigan, USA, white-tailed deer: Predictions from a spatially-explicit stochastic model.
The eradication of bovine tuberculosis (bTB), caused by Mycobacterium bovis, from cattle in many locations worldwide is complicated by endemic foci of the disease in free-ranging wildlife. Recent simulation modeling of the bTB outbreak in white-tailed deer (WTD) in Michigan, USA, suggests current management is unlikely to eradicate bTB from the core outbreak area (DMU 452) within the next three decades. However, some level of control short of eradication might sufficiently reduce transmission from deer to cattle to a point at which the negative effects of bTB on the cattle industry could be reduced or eliminated, while minimizing the negative consequences of reducing deer numbers. We extended our existing spatially-explicit, individual-based stochastic simulation model of bTB transmission in WTD to incorporate transmission to cattle, to characterize the effects of vaccination and increased harvest of WTD on cattle herd breakdown rates, to examine the effects of localized culling or vaccination of WTD in the vicinity of cattle farms, to assess the effects of concurrent deer baiting, and to determine the effect of progressive restriction of deer/cattle contact on herd breakdowns. A spatially-explicit "cattle layer" was constructed describing the spatial locations, farm size and cattle density of all farms within and directly adjacent to DMU452. Increased hunter harvest or vaccination of deer, or a combination, would likely decrease the number of cattle herd breakdowns to <1 per year in less than 15 years. Concurrent deer baiting variably increased the time necessary to achieve zero breakdowns. The prevalence of bTB in deer needed to fall below ∼0.5% before ≤1 herd breakdown per year could be expected, and below 0.1% before zero breakdowns were likely. Locally applied post-harvest deer culling or vaccination also rapidly reduced herd breakdowns. On farm biosecurity measures needed to reduce deer to cattle contact by >95% in order to reliably reduce herd breakdowns, and did not achieve zero breakdowns in the absence of other deer controls.
Arthur Rylah Institute for Environmental Research, Department of Environment and Primary Industries, 123 Brown Street, Heidelberg, Victoria 3084, Australia.
David S L
DSL
Ramsey
Wildlife Disease Laboratory, Michigan Department of Natural Resources, 4125 Beaumont Road, Room 250, Lansing, MI 48910-8106, USA. Electronic address: obriend@michigan.gov.
Daniel J
DJ
O'Brien
Animal Industry Division, Michigan Department of Agriculture and Rural Development, Constitution Hall, 525 W. Allegan Street, Lansing, MI 48909, USA.
Rick W
RW
Smith
Wildlife Disease Laboratory, Michigan Department of Natural Resources, 4125 Beaumont Road, Room 250, Lansing, MI 48910-8106, USA.
Melinda K
MK
Cosgrove
Wildlife Disease Laboratory, Michigan Department of Natural Resources, 4125 Beaumont Road, Room 250, Lansing, MI 48910-8106, USA.
Stephen M
SM
Schmitt
Rose Lake Wildlife Research Center, Michigan Department of Natural Resources, 8562 E. Stoll Road, East Lansing, MI 48823, USA.
Brent A
BA
Rudolph
D000818:Animals; D002417:Cattle; D003670:Deer; D004196:Disease Outbreaks / Q000662:veterinary*; D000072480:Farms; D005260:Female; D008297:Male; D008824:Michigan / Q000453:epidemiology; D008962:Models, Theoretical; D009163:Mycobacterium bovis / Q000502:physiology*; D011155:Population Control; D015995:Prevalence; D012308:Risk Management; D013269:Stochastic Processes; D014380:Tuberculosis, Bovine / Q000453:epidemiology / Q000382:microbiology / Q000517:prevention & control*; D014611:Vaccination / Q000662:veterinary*
Control strategies; Modelling; Mycobacterium bovis; Odocoileus virginianus; Tuberculosis; White-tailed deer