How Respiratory Pathogens Contribute to Lamb Mortality in a Poorly Performing Bighorn Sheep (Ovis canadensis) Herd

Fox, Karen A.; Jennings-Gaines, Jessica E.; Killion, Halcyon J.; Amundson, Sierra; Miller, Michael W.

doi:10.7589/2016-05-097

Cited by 26 publications

(17 citation statements)

References 18 publications

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“…Previous research has also noted little association of Pasteurellaceae species with respiratory disease in bighorn sheep populations [ 18 ]. However, leukotoxigenic Pasteurellaceae have been experimentally shown to cause pneumonia in bighorn sheep but not domestic sheep [ 12 , 28 , 58 , 59 ], Pasteurellaceae are commonly hosted by healthy domestic sheep [ 60 ], bighorn sheep typically develop pneumonia when co-penned with healthy domestic sheep [ 13 ], and Pasteurellaceae are commonly involved in the pathology of pneumonia in bighorn sheep [ 17 , 26 , 27 ]. These lines of evidence suggest that Pasteurellaceae pose a disease risk to bighorn sheep, particularly in populations where M .…”

Section: Discussionmentioning

confidence: 99%

Respiratory pathogens and their association with population performance in Montana and Wyoming bighorn sheep populations

et al. 2018

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Respiratory disease caused by Mycoplasma ovipneumoniae and Pasteurellaceae poses a formidable challenge for bighorn sheep (Ovis canadensis) conservation. All-age epizootics can cause 10–90% mortality and are typically followed by multiple years of enzootic disease in lambs that hinders post-epizootic recovery of populations. The relative frequencies at which these epizootics are caused by the introduction of novel pathogens or expression of historic pathogens that have become resident in the populations is unknown. Our primary objectives were to determine how commonly the pathogens associated with respiratory disease are hosted by bighorn sheep populations and assess demographic characteristics of populations with respect to the presence of different pathogens. We sampled 22 bighorn sheep populations across Montana and Wyoming, USA for Mycoplasma ovipneumoniae and Pasteurellaceae and used data from management agencies to characterize the disease history and demographics of these populations. We tested for associations between lamb:ewe ratios and the presence of different respiratory pathogen species. All study populations hosted Pasteurellaceae and 17 (77%) hosted Mycoplasma ovipneumoniae. Average lamb:ewe ratios for individual populations where both Mycoplasma ovipneumoniae and Pasteurellaceae were detected ranged from 0.14 to 0.40. However, average lamb:ewe ratios were higher in populations where Mycoplasma ovipneumoniae was not detected (0.37, 95% CI: 0.27–0.51) than in populations where it was detected (0.25, 95% CI: 0.21–0.30). These findings suggest that respiratory pathogens are commonly hosted by bighorn sheep populations and often reduce recruitment rates; however ecological factors may interact with the pathogens to determine population-level effects. Elucidation of such factors could provide insights for management approaches that alleviate the effects of respiratory pathogens in bighorn sheep. Nevertheless, minimizing the introduction of novel pathogens from domestic sheep and goats remains imperative to bighorn sheep conservation.

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Section: Discussionmentioning

confidence: 99%

Respiratory pathogens and their association with population performance in Montana and Wyoming bighorn sheep populations

et al. 2018

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“…The diverse histopathologic lesions observed in experimental and naturally occurring bighorn sheep pneumonia, range from those typical of Mycoplasma infections (lymphocytic cuffing around airways and hypertrophy of the bronchial respiratory epithelium) to the often more dramatic and severe hemorrhagic, edematous, and necrotic lesions resulting from secondary bacterial infections (Miller , Besser et al , Wood et al ). This polymicrobial pneumonia is thought to occur when M. ovipneumoniae binds to and degrades the cilia of the trachea and bronchi, resulting in disruption of the mucociliary escalator (Niang et al ), the physiologic process for clearing bacteria from the lower respiratory tract.…”

Section: Characteristics Of Respiratory Disease In Individualsmentioning

confidence: 99%

Pneumonia in bighorn sheep: Risk and resilience

Manlove²,

et al. 2017

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Infectious disease contributed to historical declines and extirpations of bighorn sheep (Ovis canadensis) in North America and continues to impede population restoration and management. Reports of pneumonia outbreaks in freeranging bighorn sheep following contact with domestic sheep have been validated by the results of 13 captive commingling experiments. However, ecological and etiological complexities still hinder our understanding and control of respiratory disease in wild sheep. In this paper, we review the literature and summarize recent data to present an overview of the biology and management of pneumonia in bighorn sheep. Many factors contribute to this population-limiting disease, but a bacterium (Mycoplasma ovipneumoniae) host-specific to Caprinae and commonly carried by healthy domestic sheep and goats, appears to be a primary agent necessary for initiating epizootics. All-age epizootics are usually associated with significant population declines, but mortality rates vary widely and factors influencing disease severity are not well understood. Once introduced, M. ovipneumoniae can persist in bighorn sheep populations for decades. Carrier females may transmit the pathogen to their susceptible lambs, triggering fatal pneumonia outbreaks in nursery groups, which limit recruitment and slow or prevent population recovery. The demographic costs of disease persistence can be equal to or greater than the impacts of the initial epizootic. Strain typing suggests that spillover of M. ovipneumoniae into bighorn sheep populations from domestic small ruminants is ongoing and that consequences of spillover are amplified by movements of infected bighorn sheep across populations. Therefore, current disease management strategies focus on reducing risk of spillover from reservoir populations of domestic sheep and goats and on limiting transmission among bighorn sheep.

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“…Bronchopneumonia of bighorn sheep is associated with several bacterial pathogens, including M. ovipneumoniae, Mannheimia spp., and Bibersteinia spp. (Cassirer et al , Dassanayake et al , Heinse et al , Wood et al ). The etiology of the disease is complex and typically involves the presence of M. ovipneumoniae (Besser et al ).…”

Section: Discussionmentioning

confidence: 99%

Ecotypic variation in population dynamics of reintroduced bighorn sheep

2017

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Selection of bighorn sheep (Ovis canadensis) for translocation historically has been motivated by preservation of subspecific purity rather than by adaptation of source stocks to similar environments. Our objective was to estimate cause-specific, annual, and age-specific mortality of introduced bighorn sheep that originated at low elevations in southern British Columbia, Canada (BC ecotype), or in the Missouri River Breaks region of central Montana, USA (MT ecotype). In North Dakota, USA, mortality was similar and typically low for adult female bighorn sheep from Montana (0.09 AE 0.029 [SE]) and British Columbia (0.08 AE 0.017) during 2000-2016. Median life expectancy was 11 years for females that reached adulthood (2 yrs old); however, mortality accelerated with age and reached 86% by age 16. Mortalities resulted primarily from low rates of predation, disease, accidents, and unknown natural causes (<0.04 [upper 90% CI]). Similar survival rates of female bighorn sheep from British Columbia and Montana, coupled with greater recruitment of bighorn sheep from Montana, resulted in a greater projected rate of increase for the MT ecotype (l ¼ 1.21) than for the BC ecotype (1.02), and a more youthful age structure. These results support translocation of bighorn sheep from areas that are environmentally similar to areas that will be stocked. Potential benefits include more rapid population growth, greater resilience to and more rapid recovery from densityindependent losses, an increased possibility that rapidly growing populations will expand into adjacent habitat, increased hunter opportunity, increased connectivity among herds, and a more complete restoration of ecosystem processes. Ó 2017 The Wildlife Society.

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How Respiratory Pathogens Contribute to Lamb Mortality in a Poorly Performing Bighorn Sheep (Ovis canadensis) Herd

Abstract: BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Cited by 26 publications

References 18 publications

Respiratory pathogens and their association with population performance in Montana and Wyoming bighorn sheep populations

Respiratory pathogens and their association with population performance in Montana and Wyoming bighorn sheep populations

Pneumonia in bighorn sheep: Risk and resilience

Ecotypic variation in population dynamics of reintroduced bighorn sheep

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