Pion S D S, Demanou M, Oudin B, Boussinesq M
Laboratoire mixte IRD (Institut de Recherche pour le Développement) - CPC (Centre Pasteur du Cameroun) d'Epidémiologie et de Santé publique, Centre Pasteur du Cameroun, Yaoundé.
Ann Trop Med Parasitol. 2005 Jul;99(5):491-500. doi: 10.1179/136485905X51300.
No microfilariae are detectable in a significant percentage of those infected with the filarial worm Loa loa. While the probability of an infected individual becoming microfilaraemic is known to increase with age, the mechanisms underlying this trend are not well understood. Epidemiological data from an endemic village in central Cameroon were therefore explored, in an attempt to determine if, after taking into account any history of filaricidal treatment, the presence of Loa microfilaraemia in an individual was related to his/her gender, age, and/or exposure to the human-infective larvae of the parasite. An index of exposure, based on the monthly transmission potentials of the Chrysops in each of the main types of vegetation in a village and on the activity schedule of each inhabitant of the village, was developed. The results of the data analysis confirm that the acquisition of microfilaraemia is gender-dependent (males generally being more likely to be microfilaraemic than females), and indicate that, in males, a high level of exposure to infective larvae determines the shift from amicrofilaraemic to microfilaraemic status. They also indicate that filaricidal treatments have a long-lasting suppressive effect on Loa microfilaraemia, an observation that may have important implications for any strategy to limit the risk of Loa-associated encephalopathy following ivermectin treatment.
在感染罗阿丝虫的人群中，有相当比例的人检测不到微丝蚴。虽然已知受感染个体出现微丝蚴血症的概率会随着年龄增长而增加，但这种趋势背后的机制尚未完全明确。因此，对喀麦隆中部一个流行村庄的流行病学数据进行了研究，试图确定在考虑任何杀丝虫治疗史后，个体中罗阿微丝蚴血症的存在是否与其性别、年龄和/或接触该寄生虫的人感染性幼虫有关。基于村庄中每种主要植被类型的金蝇每月传播潜力以及村庄每个居民的活动时间表，制定了一个接触指数。数据分析结果证实，微丝蚴血症的获得具有性别依赖性（男性通常比女性更易出现微丝蚴血症），并表明在男性中，高暴露于感染性幼虫会导致从无微丝蚴血症状态转变为微丝蚴血症状态。结果还表明，杀丝虫治疗对罗阿微丝蚴血症具有持久的抑制作用，这一观察结果可能对限制伊维菌素治疗后罗阿相关脑病风险的任何策略具有重要意义。
