AbstractGenetic variation in the susceptibility of cattle toMycobacterium bovisinfection exists in differences between families and species, but not breeds. Susceptibility toM. bovisinfection increases with age of cattle. Natural exposure toM. bovisor environmental mycobacteria may assist in the development of specific immunity, but there is no direct evidence for such immunological priming of tuberculosis resistance in cattle. This has, however, been demonstrated in humans and other animals. Since non-specific mechanisms have a role in protective immunity, developing an effective vaccine will be difficult, even though some protection of other species has been achieved. Immunological suppression in the periparturient period can produce anergic reactors, which may act as a constant source of infection for cattle-to-cattle transmission. Circumstantial evidence suggests that an adequate intake of mineral, vitamin and protein reduces the susceptibility of cattle. Although weather patterns have been implicated in the susceptibility of herds toM. bovisinfection, there is insufficient information to determine the risk factors precisely. It is concluded that some reduction in the susceptibility of cattle toM. bovisinfection can be achieved by modifications to the management system to minimize risk factors, but that a considerable amount of further research is required.
摘要 牛对牛分枝杆菌感染敏感性的遗传变异存在家系和物种之间的差异,但不存在品种之间的差异。对牛分枝杆菌感染的易感性随牛的年龄而增加。牛分枝杆菌环境分枝杆菌的自然暴露可能有助于特异性免疫力的发展,但目前还没有直接证据表明牛对结核病的抵抗力是由这种免疫启动的。不过,这在人类和其他动物身上得到了证实。由于非特异性机制在保护性免疫中发挥作用,因此,尽管其他物种已经获得了一定程度的保护,但开发有效疫苗仍将十分困难。围产期的免疫抑制会产生过敏反应者,这可能成为牛与牛之间传播的持续感染源。间接证据表明,摄入充足的矿物质、维生素和蛋白质可降低牛的易感性。虽然天气模式与牛群对牛海绵状瘤病毒感染的易感性有关,但没有足够的信息来准确确定风险因素。结论是,通过调整管理系统以尽量减少风险因素,可在一定程度上降低牛群对牛海绵状瘤病毒感染的易感性,但仍需开展大量的进一步研究。