Wildlife Health Center & One Health Institute, School of Veterinary Medicine, University of California, Davis, 1089 Veterinary Medicine Drive, Davis, CA 95616, USA.
Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, 335A Animal Science Veterinary Medicine Building, 1988 Fitch Avenue, St. Paul, MN 55108, USA.
Prev Vet Med. 2014 Aug 1;115(3-4):157-65. doi: 10.1016/j.prevetmed.2014.04.014. Epub 2014 May 5.
Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is a disease of zoonotic concern, especially in countries with no control programs in livestock and where routine pasteurization of milk is not practiced. In Tanzania, bTB is widespread in livestock and has been diagnosed in humans; however, herd bTB testing is primarily carried out for bTB-free certification in commercial dairy herds at the expense of the dairy cattle owner. For rural livestock holders, such an expense is prohibitive, and consequently there is no control of bTB in most areas. Although effective long-term solutions to control bTB in livestock are desirable, there is a need to assess the effect of preventive measures on reducing human exposure to bTB in such settings. We utilized locally relevant cattle herd characteristics and management data from the Health for Animals and Livelihood Improvement (HALI) project in south-central Tanzania to build a Reed-Frost model that compared the efficacy of alternative methods aimed at reducing the exposure of humans to infectious milk from a typical pastoralist cattle herd. During a 10-year simulation period, the model showed that boiling milk 80% of the time is necessary to obtain a reduction in liters of infectious milk approximately equivalent to what would be obtained with a standard 2-year testing and removal regimen, and that boiling milk was more effective than animal test and removal early in the time period. In addition, even with testing and removing infected cattle, a residual risk of exposure to infectious milk remained due to imperfect sensitivity of the skin test and a continuous risk of introduction of infectious animals from other herds. The model was sensitive to changes in initial bTB prevalence but not to changes in herd size. In conclusion, continuous complimentary treatment of milk may be an effective strategy to reduce human exposure to M. bovis-infected milk in settings where bTB is endemic and a comprehensive bTB control program is yet to be implemented.
牛型结核（bTB）由牛分枝杆菌引起，是一种人畜共患疾病，尤其是在没有家畜控制计划且未实行常规牛奶巴氏消毒的国家。在坦桑尼亚，bTB 在牲畜中广泛传播，并且已经在人类中确诊；然而，畜群 bTB 检测主要是为了在商业奶牛群中获得无 bTB 认证，这需要花费奶牛所有者的资金。对于农村牲畜饲养者来说，这种费用是禁止的，因此大多数地区都没有对 bTB 进行控制。尽管人们希望找到长期有效的方法来控制牲畜中的 bTB，但在这种情况下，有必要评估预防措施对减少人类接触 bTB 的效果。我们利用坦桑尼亚中南部 Health for Animals and Livelihood Improvement (HALI) 项目中的当地相关牛群特征和管理数据，构建了一个 Reed-Frost 模型，该模型比较了旨在减少人类接触传染性牛奶的替代方法的效果，这些方法针对的是一个典型的牧民牛群。在 10 年的模拟期间，该模型表明，要使传染性牛奶的减少量与标准的 2 年检测和淘汰方案相当，需要将牛奶煮沸 80%的时间，并且在早期阶段，煮沸牛奶比早期检测和淘汰动物更有效。此外，即使对感染牛进行检测和淘汰，由于皮肤测试的敏感性不高以及来自其他畜群的传染性动物持续引入的风险，仍然存在接触传染性牛奶的残留风险。该模型对初始 bTB 流行率的变化敏感，但对畜群规模的变化不敏感。总之，在尚未实施全面 bTB 控制计划的情况下，对牛奶进行持续的补充治疗可能是减少人类接触地方性 bTB 感染牛奶的有效策略。
