Wacher T J, Milligan P J, Rawlings P, Snow W F
International Trypanotolerance Centre, Banjul, The Gambia.
Parasitology. 1994 Aug;109 ( Pt 2):149-62. doi: 10.1017/s0031182000076265.
The severity of the trypanosomiasis problem in a particular location is traditionally assessed in terms of a challenge index-the product of some measure of tsetse abundance and infection-rate-which is assumed to be proportional to the force of infection. However, this index masks variation in the force of infection between herds and among individuals within herds. It is also not comparable between sites since the relative abundance of tsetse to hosts may vary. We have studied spatial distribution of herds of cattle in relation to tsetse in The Gambia and calculated an index of challenge based on the ratio of vectors to hosts over the livestock ranging area. This index is strongly correlated with estimates of the force of infection calculated from the incidence of infection in susceptible zebu; and it provides information on heterogeneity in exposure of different herds to tsetse.
传统上，特定地区锥虫病问题的严重程度是通过一个挑战指数来评估的，该指数是采采蝇数量的某种度量与感染率的乘积，假定它与感染强度成正比。然而，这个指数掩盖了不同畜群之间以及同一畜群内个体之间感染强度的差异。由于采采蝇与宿主的相对数量可能不同，该指数在不同地点之间也无法进行比较。我们研究了冈比亚牛群相对于采采蝇的空间分布，并根据牲畜活动范围内病媒与宿主的比例计算了一个挑战指数。这个指数与根据易感瘤牛的感染发病率计算出的感染强度估计值密切相关，并且它提供了不同畜群接触采采蝇的异质性信息。
