Shifting brucellosis risk in livestock coincides with spreading seroprevalence in elk
Shifting brucellosis risk in livestock coincides with spreading seroprevalence in elk
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DOI：
10.1371/journal.pone.0178780
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发表时间：
2017-06-13
期刊：
影响因子：
3.7
通讯作者：
Edwards, William H.
中科院分区：
文献类型：
--
作者：
Brennan, Angela;Cross, Paul C.;Edwards, William H.
当罕见的疫情在大片地区发生时，跟踪和预防疾病从野生动物向牲畜的蔓延可能会很困难。在这些情况下，广泛的生态学研究可以帮助确定风险因素和风险模式，为管理层提供信息，减少疾病发生率。2002至2014年间，大黄石地区(GYA)的21个畜群受到布鲁氏菌病(一种由布鲁氏菌流产引起的细菌性疾病)的影响，而1990至2001年间没有发现受影响的牛群。使用贝叶斯分析，我们检查了可能与该地区受影响的牲畜群相关的几个生态协变量。我们发现，家畜风险随着时间的推移一直在增加，并从怀俄明州野生麋鹿布鲁氏菌病的历史联系向外扩展，在怀俄明州的饲养场，麋鹿在冬季补充喂养。尽管麋鹿被认为是牛感染的来源，但受影响的牲畜群的出现与整个GYA地区血清阳性麋鹿的密度只有微弱的关联。然而，牲畜风险的转变确实与最近未喂养的麋鹿种群中布鲁氏菌病血清阳性率的上升相一致。由于未喂养的麋鹿布鲁氏菌病的增加可能源于已喂养的麋鹿体内的高水平疾病，与疾病相关的饲养麋鹿的成本可能已经在整个GYA发生，而不仅仅是在饲养场周围。我们的结果表明，在未喂养的麋鹿血清阳性率较高的地区集中缓解疾病可以减少布鲁氏菌病对牲畜的溢出。我们还强调需要更好地了解溢出事件的流行病学，包括疾病检测、产犊和受感染牲畜流动的详细历史。最后，我们建议使用病例对照研究来调查对牲畜风险有重要影响的地方因素。
Tracking and preventing the spillover of disease from wildlife to livestock can be difficult when rare outbreaks occur across large landscapes. In these cases, broad scale ecological studies could help identify risk factors and patterns of risk to inform management and reduce incidence of disease. Between 2002 and 2014, 21 livestock herds in the Greater Yellow-stone Area (GYA) were affected by brucellosis, a bacterial disease caused by Brucella abortus, while no affected herds were detected between 1990 and 2001. Using a Bayesian analysis, we examined several ecological covariates that may be associated with affected livestock herds across the region. We showed that livestock risk has been increasing over time and expanding outward from the historical nexus of brucellosis in wild elk on Wyoming's feeding grounds where elk are supplementally fed during the winter. Although elk were the presumed source of cattle infections, occurrences of affected livestock herds were only weakly associated with the density of seropositive elk across the GYA. However, the shift in livestock risk did coincide with recent increases in brucellosis seroprevalence in unfed elk populations. As increasing brucellosis in unfed elk likely stemmed from high levels of the disease in fed elk, disease-related costs of feeding elk have probably been incurred across the entire GYA, rather than solely around the feeding grounds. Our results suggest that focused disease mitigation in areas where seroprevalence in unfed elk is high could reduce the spillover of brucellosis to livestock. We also highlight the need to better understand the epidemiology of spillover events with detailed histories of disease testing, calving, and movement of infected livestock. Finally, we recommend using case-control studies to investigate local factors important to livestock risk.