Bissan Y, Doucouré K, Back C, Hougard J M, Agoua H, Guillet P, Konaré M, Harding P, Musa J, Dumbuya F
OMS/OCP, Bamako, Mali.
Ann Soc Belg Med Trop. 1994 Jun;74(2):129-47.
The movements of human populations towards the mining wealth of the northern parts of Sierra Leone are favorable to a high contact rate between onchocerciasis patients coming from the south-western area of this country and the vector species Simulium yahense and Simulium squamosum which assume the essential of onchocerciasis transmission in the above-mentioned mining area. In fact, the Onchocerca volvulus strains concerned by this contact seem to be more pathogenic than those locally transmitted. In order to assess the danger it could represent for the Onchocerciasis Control Programme in West Africa, we carried out the experimental study of transmission which may result from this contact when more or less infected onchocerciasis patients are involved. The results indicated that this transmission by S. yahense may reach high proportions only when heavily infected onchocerciasis patients are implicated. We took also notice of the low capacity of S. squamosum to transmit the O. volvulus strains from the south-western Sierra Leone, irrespective of the microfilarial load of patients. Thus, in the most favorable conditions of a high parasite-vector contact of the study, involvement of S. yahense and onchocerciasis patients with high skin microfilarial loads is the only occurrence to which a high risk of intensive transmission may be related. The authors consider that the probability of such a risk occurring will be drastically reduced, due to the considerable decrease of skin microfilarial loads in human communities which regularly have the advantage of ivermectin (Mectizan) mass treatments.
人群向塞拉利昂北部矿区的迁移，有利于该国西南部地区的盘尾丝虫病患者与蚋属的雅氏蚋和鳞状蚋这两种媒介物种之间保持较高的接触率，而上述矿区盘尾丝虫病的传播主要由这两种蚋来完成。实际上，因这种接触而涉及的盘尾丝虫菌株似乎比当地传播的菌株致病性更强。为了评估这可能给西非盘尾丝虫病控制计划带来的风险，我们开展了一项实验研究，以探究当涉及不同感染程度的盘尾丝虫病患者时，这种接触可能导致的传播情况。结果表明，只有当涉及重度感染的盘尾丝虫病患者时，雅氏蚋引发的这种传播比例才会很高。我们还注意到，无论患者的微丝蚴负荷如何，鳞状蚋传播来自塞拉利昂西南部的盘尾丝虫菌株的能力都很低。因此，在该研究中寄生虫与媒介接触率较高的最有利条件下，雅氏蚋和皮肤微丝蚴负荷高的盘尾丝虫病患者的接触，是唯一可能导致高强度传播高风险的情况。作者认为，由于定期接受伊维菌素（美迪善）群体治疗的人群皮肤微丝蚴负荷大幅下降，这种风险发生的可能性将大大降低。
