Simukoko H, Marcotty T, Phiri I, Vercruysse J, Van den Bossche P
University of Zambia, School of Veterinary Medicine, Zambia.
Acta Trop. 2007 Aug;103(2):98-101. doi: 10.1016/j.actatropica.2007.05.011. Epub 2007 May 24.
On the plateau of eastern Zambia, trypanosomosis is endemic. Glossina morsitans morsitans Westwood (Diptera: Glossinidae), the only tsetse species present, is almost entirely dependent on livestock as its source of food with cattle being the most preferred host. To determine if tsetse challenge is distributed equally over the various age categories and sexes within a cattle herd, a longitudinal study of trypanosomosis incidence was conducted during the rainy season. A total of 354 head of cattle consisting of 40% oxen, 30% cows, 15% young stock, 13% calves and 2% bulls were sampled for three consecutive months and their infection statuses determined using the PCR-RFLP technique as diagnostic method. Results indicated that there were significant differences (P<0.001) in the proportion of infected animals between the various categories. In oxen, the risk of infection was 5.6 times higher than in calves. Those results suggest heterogeneity in the challenge by tsetse flies and are in line with entomological observations on the feeding preference of tsetse on cattle. The implications of these results for the control of trypanosomosis in Eastern Province and other epidemiologically related areas are discussed.
在赞比亚东部高原，锥虫病呈地方流行。现有的唯一采采蝇物种——刺舌蝇（Glossina morsitans morsitans Westwood，双翅目：舌蝇科）几乎完全依赖家畜作为食物来源，其中牛是最受青睐的宿主。为了确定采采蝇对牛群中不同年龄类别和性别的攻击是否均匀分布，在雨季期间对锥虫病发病率进行了一项纵向研究。总共对354头牛进行了连续三个月的采样，其中公牛占40%，母牛占30%，青年牛占15%，犊牛占13%，公牛占2%，并使用PCR-RFLP技术作为诊断方法确定它们的感染状况。结果表明，不同类别之间感染动物的比例存在显著差异（P<0.001）。在公牛中，感染风险比犊牛高5.6倍。这些结果表明采采蝇的攻击存在异质性，并且与关于采采蝇对牛的取食偏好的昆虫学观察结果一致。本文讨论了这些结果对东部省及其他流行病学相关地区锥虫病控制的意义。
