Risk Factors for Bovine Tuberculosis (bTB) in Cattle in Ethiopia
Risk Factors for Bovine Tuberculosis (bTB) in Cattle in Ethiopia
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DOI：
10.1371/journal.pone.0159083
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发表时间：
2016-07-12
期刊：
影响因子：
3.7
通讯作者：
de Boer, Willem F.
中科院分区：
文献类型：
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作者：
Dejene, Sintayehu W.;Heitkonig, Ignas M. A.;de Boer, Willem F.
牛结核病（bTB）感染通常与个体牛的年龄、性别、身体状况以及牧群组成、牛群运动、牧群规模、生产系统和与野生动物（包括bTB维持宿主）的接近程度等畜牧业实践相关。2013年11月至2015年4月，我们在阿法尔地区和阿瓦什国家公园测试了这些因素与bTB流行率之间的相关性。bTB是埃塞俄比亚高原牛的地方病。采用比较皮内结核菌素试验（CITT）对来自102个畜群的2550头牛进行了bTB检测。通过对牧民和牧场主进行半结构化访谈，收集了牧群结构、牧群流动、管理和生产系统、牲畜转移以及与野生动物接触等方面的数据。牛bTB的个体总体流行率为5.5%，牛群流行率为46%。采用随机群体效应的广义线性混合模型分析了每个群体中牛群反应的危险因素。牛的年龄越大、身体状况越差，bTB阳性检出率越高，但性别、泌乳状态和生殖状态与bTB的检出率无相关性。在牧群水平上，一般线性模型显示，游牧牧群比定居牧群的bTB患病率更高。模型平均分析确定畜群规模、与野生动物接触以及畜群规模与与野生动物接触的相互作用是牛中bTB流行的重要危险因素。随后的结构方程模型表明，与野生动物接触的概率受到畜群规模的影响，通过畜群的运动。较大的畜群移动得更多，在更大的地区放牧，因此在有野生动物的地区放牧并与受感染的牛或受感染的野生动物宿主接触的可能性增加，从而增加了感染bTB的机会。因此，未来牧区牛的bTB控制策略应将畜群规模和移动作为重要的风险因素。
Bovine tuberculosis (bTB) infection is generally correlated with individual cattle's age, sex, body condition, and with husbandry practices such as herd composition, cattle movement, herd size, production system and proximity to wildlife-including bTB maintenance hosts. We tested the correlation between those factors and the prevalence of bTB, which is endemic in Ethiopia's highland cattle, in the Afar Region and Awash National Park between November 2013 and April 2015. A total of 2550 cattle from 102 herds were tested for bTB presence using the comparative intradermal tuberculin test (CITT). Data on herd structure, herd movement, management and production system, livestock transfer, and contact with wildlife were collected using semi-structured interviews with cattle herders and herd owners. The individual overall prevalence of cattle bTB was 5.5%, with a herd prevalence of 46%. Generalized Linear Mixed Models with a random herd-effect were used to analyse risk factors of cattle reactors within each herd. The older the age of the cattle and the lower the body condition the higher the chance of a positive bTB test result, but sex, lactation status and reproductive status were not correlated with bTB status. At herd level, General Linear Models showed that pastoral production systems with transhumant herds had a higher bTB prevalence than sedentary herds. A model averaging analysis identified herd size, contact with wildlife, and the interaction of herd size and contact with wildlife as significant risk factors for bTB prevalence in cattle. A subsequent Structural Equation Model showed that the probability of contact with wildlife was influenced by herd size, through herd movement. Larger herds moved more and grazed in larger areas, hence the probability of grazing in an area with wildlife and contact with either infected cattle or infected wildlife hosts increased, enhancing the chances for bTB infection. Therefore, future bTB control strategies in cattle in pastoral areas should consider herd size and movement as important risk factors.