Benavides J A, Caillaud D, Scurlock B M, Maichak E J, Edwards W H, Cross P C
Department of Ecology, Montana State University, 310 Lewis Hall, Bozeman, MT, 59717, USA.
Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.
Ecohealth. 2017 Jun;14(2):234-243. doi: 10.1007/s10393-017-1235-z. Epub 2017 May 15.
Serological data are one of the primary sources of information for disease monitoring in wildlife. However, the duration of the seropositive status of exposed individuals is almost always unknown for many free-ranging host species. Directly estimating rates of antibody loss typically requires difficult longitudinal sampling of individuals following seroconversion. Instead, we propose a Bayesian statistical approach linking age and serological data to a mechanistic epidemiological model to infer brucellosis infection, the probability of antibody loss, and recovery rates of elk (Cervus canadensis) in the Greater Yellowstone Ecosystem. We found that seroprevalence declined above the age of ten, with no evidence of disease-induced mortality. The probability of antibody loss was estimated to be 0.70 per year after a five-year period of seropositivity and the basic reproduction number for brucellosis to 2.13. Our results suggest that individuals are unlikely to become re-infected because models with this mechanism were unable to reproduce a significant decline in seroprevalence in older individuals. This study highlights the possible implications of antibody loss, which could bias our estimation of critical epidemiological parameters for wildlife disease management based on serological data.
血清学数据是野生动物疾病监测的主要信息来源之一。然而，对于许多自由放养的宿主物种而言，受感染个体血清阳性状态的持续时间几乎总是未知的。直接估计抗体丧失率通常需要在个体血清转化后进行困难的纵向采样。相反，我们提出了一种贝叶斯统计方法，将年龄和血清学数据与一个机械流行病学模型相联系，以推断大黄石生态系统中麋鹿（加拿大马鹿）的布鲁氏菌病感染情况、抗体丧失概率和恢复率。我们发现，血清阳性率在10岁以上有所下降，没有疾病导致死亡的证据。在血清阳性持续五年后，抗体丧失概率估计为每年0.70，布鲁氏菌病的基本繁殖数为2.13。我们的结果表明，个体不太可能再次感染，因为具有这种机制的模型无法再现老年个体血清阳性率的显著下降。这项研究突出了抗体丧失可能产生的影响，这可能会使我们基于血清学数据对野生动物疾病管理的关键流行病学参数的估计产生偏差。
