Yang Anni, Gomez Juan Pablo, Haase Catherine G, Proffitt Kelly M, Blackburn Jason K
1 Spatial Epidemiology and Ecology Research Laboratory, Department of Geography, University of Florida, 3141 Turlington Hall, Gainesville, Florida 32611, USA.
2 Emerging Pathogens Institute, University of Florida, 2055 Mowry Road, Gainesville, Florida 32611, USA.
J Wildl Dis. 2019 Apr;55(2):304-315. doi: 10.7589/2018-01-011. Epub 2018 Oct 2.
Brucellosis, caused by bacteria in the genus Brucella, is an infectious zoonosis affecting animals and humans worldwide. Free-ranging Rocky Mountain elk ( Cervus canadensis nelsoni) and bison ( Bison bison) in the Greater Yellowstone Ecosystem (areas of southwestern Montana, eastern Idaho, and northwestern Wyoming, US) are the self-sustaining reservoirs of bovine brucellosis ( Brucella abortus) and elk are considered the primary source of livestock infections. It has been hypothesized that Brucella-exposed elk might have different physiologic status (pregnancy rates and body condition) and migration behaviors than would healthy elk. Here we tested the effects of brucellosis serologic status on pregnancy rates and winter ingesta free body fat of 100 female elk in southwestern Montana. We also evaluated the effects of serologic status on two characteristics of spring migration behavior, migration types (migrant, mixed migrant, resident, disperser, nomad, and undetermined type) and timing (start and end dates and duration). The migration behaviors were quantified using a model-driven approach based on the relative net squared displacement. We detected a significant difference (P=0.003) in pregnancy rates between seropositive and seronegative elk, with about a 30% drop in seropositive individuals. However, we did not detect differences in body fat between seropositive and seronegative elk or differences in either migration type or timing of spring migration. These results confirmed that the major effect of brucellosis in free-ranging elk is associated with reproduction.
布鲁氏菌病由布鲁氏菌属细菌引起，是一种影响全球动物和人类的传染性人畜共患病。在大黄石生态系统（美国蒙大拿州西南部、爱达荷州东部和怀俄明州西北部地区）中自由放养的落基山麋鹿（加拿大马鹿尼尔森亚种）和野牛是牛布鲁氏菌病（流产布鲁氏菌）的自我维持宿主，麋鹿被认为是牲畜感染的主要来源。据推测，接触布鲁氏菌的麋鹿可能与健康麋鹿具有不同的生理状态（妊娠率和身体状况）和迁徙行为。在此，我们测试了布鲁氏菌病血清学状态对蒙大拿州西南部100只雌性麋鹿妊娠率和冬季摄入物游离体脂肪的影响。我们还评估了血清学状态对春季迁徙行为的两个特征的影响，即迁徙类型（迁徙者、混合迁徙者、定居者、扩散者、游牧者和未确定类型）和时间（开始和结束日期以及持续时间）。使用基于相对净平方位移的模型驱动方法对迁徙行为进行量化。我们检测到血清阳性和血清阴性麋鹿之间的妊娠率存在显著差异（P = 0.003），血清阳性个体的妊娠率下降了约30%。然而，我们未检测到血清阳性和血清阴性麋鹿之间的体脂差异，也未检测到春季迁徙类型或时间的差异。这些结果证实，布鲁氏菌病对自由放养麋鹿的主要影响与繁殖有关。
