Bovine tuberculosis infection in wild mammals in the South-West region of England: A survey of prevalence and a semi-quantitative assessment of the relative risks to cattle

Delahay, Richard J.; Smith, Graham C.; Barlow, Alex; Walker, Neil J.; Harris, Audrey; Clifton-Hadley, R. S.; Cheeseman, C. L.

doi:10.1016/j.tvjl.2005.11.011

Cited by 153 publications

(185 citation statements)

References 28 publications

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“…However, estimates of M. bovis excretion likelihood and magnitude remained uncertain owing to the absence of data on the relationship between histopathologic observations and the excretion of M. bovis bacilli. Nevertheless, fallow deer had the highest risk score in both studies, which is consistent with the contention (Delahay et al, 2007) that where they are present and infected with M. bovis they are likely to pose the greatest potential risk to cattle amongst the four deer species investigated.…”

Section: Discussionsupporting

confidence: 86%

“…Our median M. bovis pressure risk estimates were lower than those presented by Delahay et al (2007) for all deer, but associated uncertainty was considerably higher. This may, at least in part, have been due to Delahay et al (2007) presenting median and interquartile ranges of risk estimates, in contrast to median and 95th percentiles in the present study.…”

Section: Discussioncontrasting

confidence: 76%

“…This may, at least in part, have been due to Delahay et al (2007) presenting median and interquartile ranges of risk estimates, in contrast to median and 95th percentiles in the present study. Moreover, whereas Delahay et al (2007) used expert opinion to fill knowledge gaps on bacterial excretion and deer contact with cattle, we used empirical data. However, estimates of M. bovis excretion likelihood and magnitude remained uncertain owing to the absence of data on the relationship between histopathologic observations and the excretion of M. bovis bacilli.…”

Section: Discussioncontrasting

confidence: 62%

“…However, the potential role of wild deer in perpetuating bTB in cattle has yet to be adequately evaluated. Delahay et al (2007) carried out surveys of M. bovis infection in wild mammal carcasses collected from cattle bTB hot spots in southwest England. They used bTB prevalence estimates, published information on deer biology, and expert opinion on bTB epidemiology and the behavior and ecology of each species to assess the potential risks of transmission to cattle.…”

Section: Introductionmentioning

confidence: 99%

“…The process followed by Delahay et al (2007) was a form of risk assessment. In essence, risk assessment requires identification of hazards (in this context, the potential for M. bovis excreted by wildlife to infect cattle) and an understanding of exposure to the target system (the likelihood that this potential will be realized; Calow, 1998).…”

Section: Introductionmentioning

confidence: 99%

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Estimating the Risk of Cattle Exposure to Tuberculosis Posed by Wild Deer Relative to Badgers in England and Wales

Ward

Smith

Etherington

et al. 2009

Journal of Wildlife Diseases

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ABSTRACT:Wild deer populations in Great Britain are expanding in range and probably in numbers, and relatively high prevalence of bovine tuberculosis (bTB, caused by infection with Mycobacterium bovis) in deer occurs locally in parts of southwest England. To evaluate the M. bovis exposure risk posed to cattle by wild deer relative to badgers in England and Wales, we constructed and parameterized a quantitative risk model with the use of information from the literature (on deer densities, activity patterns, bTB epidemiology, and pathology) and contemporary data on deer, cattle, and badger (Meles meles) distribution and abundance. The median relative risk score for each of the four deer species studied-red (Cervus elaphus), fallow (Dama dama), and roe (Capreolus capreolus) deer, and muntjac (Muntiacus reevesi)-was lower than unity (the relative risk set for badgers, the putative main wildlife reservoir of M. bovis in England and Wales). However, the 95th percentiles associated with risk estimates were large, and the upper limits for all four deer species exceeded unity. Although M. bovis exposure risks to cattle from deer at pasture are likely to be lower than those from badgers across most areas of England and Wales where cattle are affected by bTB because these areas coincide with high-density badger populations but not high-density deer populations, we predict the presence of localized areas where relative risks posed by deer may be considerable. Moreover, wherever deer are infected, risks to cattle may be additive to those posed by badgers. There are considerable knowledge gaps associated with bTB in deer, badgers, and cattle, and data available for model parameterization were generally of low quality and high variability, and consequently model output were subject to some uncertainty. Improved estimates of the proportion of time that deer of each species spend at pasture, the likelihood and magnitude of M. bovis excretion, and local badger and deer densities appear most important for improving estimates of relative risk in this system.

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Section: Discussionsupporting

confidence: 86%

Section: Discussioncontrasting

confidence: 76%