Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Prev Vet Med. 2013 Feb 1;108(2-3):148-58. doi: 10.1016/j.prevetmed.2012.08.001. Epub 2012 Aug 22.
The objective of this study was to investigate the potential impacts of imperfect Mycobacterium avium subsp. paratuberculosis (MAP) vaccines on the dynamics of MAP infection in US dairy herds using a mathematical modeling approach. Vaccine-based control programs have been implemented to reduce the prevalence of MAP infection in some dairy herds; however, MAP vaccines are imperfect. Vaccines can provide partial protection for susceptible calves, reduce the infectiousness of animals shedding MAP, lengthen the latent period of infected animals, slow the progression from low shedding to high shedding in infectious animals, and reduce clinical disease. To quantitatively study the impacts of imperfect MAP vaccines, we developed a deterministic multi-group vaccination model and performed global sensitivity analyses. Our results explain why MAP vaccination might have a beneficial, negligible, or detrimental effect in the reduction of prevalence and show that vaccines that are beneficial to individual animals may not be useful for a herd-level control plan. The study suggests that high efficacy vaccines that are aimed at reducing the susceptibility of the host are the most effective in controlling MAP transmission. This work indicates that MAP vaccination should be integrated into a comprehensive control program that includes test-and-cull intervention and improved calf rearing management.
本研究旨在通过数学建模方法研究不完善的禽分枝杆菌副结核亚种（MAP）疫苗对美国奶牛场 MAP 感染动态的潜在影响。已经实施了基于疫苗的控制计划来降低一些奶牛场中 MAP 感染的流行率；然而，MAP 疫苗并不完善。疫苗可以为易感犊牛提供部分保护，降低排泄 MAP 的动物的传染性，延长感染动物的潜伏期，减缓感染动物从低排泄到高排泄的进展，并减少临床疾病。为了定量研究不完善的 MAP 疫苗的影响，我们开发了一个确定性多组疫苗接种模型，并进行了全局敏感性分析。我们的结果解释了为什么 MAP 疫苗接种可能对降低流行率产生有益、微不足道或有害的影响，并表明对个体动物有益的疫苗可能对群体水平的控制计划没有用处。该研究表明，旨在降低宿主易感性的高功效疫苗是控制 MAP 传播最有效的方法。这项工作表明，MAP 疫苗接种应纳入包括检测和淘汰干预以及改善犊牛饲养管理的综合控制计划。
