Haile D G, Mount G A, Cooksey L M
Medical and Veterinary Entomology Research Laboratory, USDA-ARS, Gainesville, Florida 32604.
J Med Entomol. 1992 Mar;29(2):246-58. doi: 10.1093/jmedent/29.2.246.
A computer model was developed to simulate the processes involved in transmission of the cattle fever parasites Babesia bovis (Babes) and Babesia bigemina (Smith & Kilborne) between cattle and Boophilus ticks. The model of Babesia transmission was combined with a dynamic life history model for population dynamics of the tick vectors, Boophilus microplus (Canestrini) and B. annulatus (Say). Epidemiological parameters and relationships in the model include the reduction in fecundity of infected ticks, rate of transovarial transmission, effect of cattle type and inoculation rate on infectivity of cattle, variation of infected cattle recovery rate with age of infection, inoculation rate, and species of parasite. Some parameters in the model were fitted by iterative simulations to produce realistic rates of Babesia infection in larval ticks. Comparisons of simulated and reported epidemiological data from one location in Australia indicated a reasonable level of validity for the model. Theoretical tick density thresholds for maintenance of Babesia in cattle and for inoculation of greater than or equal to 99.5% calves were determined by iterative simulations at 10 locations with B. microplus and six locations with B. annulatus. The model and transmission thresholds can serve as the basis for further simulation studies on strategies for control or eradication of babesiosis.
开发了一种计算机模型，以模拟牛热寄生虫双芽巴贝斯虫（巴贝斯）和牛巴贝斯虫（史密斯和基尔伯恩）在牛和微小牛蜱之间传播所涉及的过程。巴贝斯虫传播模型与蜱传播媒介微小牛蜱（卡内斯特里尼）和环形牛蜱（赛伊）种群动态的动态生活史模型相结合。模型中的流行病学参数和关系包括感染蜱的繁殖力降低、经卵传播率、牛的类型和接种率对牛感染力的影响、感染牛恢复率随感染年龄、接种率和寄生虫种类的变化。通过迭代模拟对模型中的一些参数进行拟合，以产生幼虫蜱中现实的巴贝斯虫感染率。对来自澳大利亚一个地点的模拟和报告的流行病学数据进行比较，表明该模型具有合理的有效性水平。通过在10个微小牛蜱地点和6个环形牛蜱地点进行迭代模拟，确定了牛体内维持巴贝斯虫以及接种大于或等于99.5%犊牛的理论蜱密度阈值。该模型和传播阈值可作为进一步模拟研究控制或根除巴贝斯虫病策略的基础。
