Smith G, Grenfell B T, Anderson R M
Department of Pure and Applied Biology, Imperial College, University of London.
Parasitology. 1987 Oct;95 ( Pt 2):373-88. doi: 10.1017/s0031182000057814.
The decline in faecal egg counts, characteristic of calves which have been experimentally infected with Ostertagia ostertagi, is analysed using a mathematical model in which parasite fecundity is assumed to be an inverse function of both the duration and intensity of infection. The model incorporates a description of the frequency distribution of mature parasites between hosts (which is less over-dispersed than is usual for many other helminth infections). The model provides a good overall description of the decline in faecal egg production observed during trickle and single infection experiments. The main discrepancy between a comparison of the model predictions and the results of the most detailed available series of trickle infection experiments occurs at the initial peak of egg production. The magnitude of this difference appears to be related to the worm burden at the peak of egg production. The possible mechanisms underlying density-dependent regulation of the fecundity of O. ostertagia are discussed.
利用一个数学模型分析了经实验感染奥斯特他线虫的犊牛粪便虫卵计数下降的情况，该模型假定寄生虫繁殖力是感染持续时间和强度的反函数。该模型纳入了对宿主间成熟寄生虫频率分布的描述（其分布比许多其他蠕虫感染的通常情况更不呈过度分散）。该模型对在逐步感染和单次感染实验中观察到的粪便产蛋量下降情况提供了良好的总体描述。模型预测与现有最详细的逐步感染实验系列结果之间的主要差异出现在产蛋量的初始峰值处。这种差异的大小似乎与产蛋量峰值时的虫负荷有关。讨论了奥斯特他线虫繁殖力密度依赖性调节的潜在机制。
