Akogbeto M
Centre de Recherches Entomologiques OCCGE de Cotonou, Bénin.
Ann Soc Belg Med Trop. 1995 Sep;75(3):219-27.
In a longitudinal study we have observed the fluctuation in density of two Anopheles populations responsible for malaria transmission in a village built on a brackish lake. The two A. gambiae complex species are A. melas and A. gambiae s.s. The former is the most abundant (88%). The brackish lake ecosystem gives to both species possibilities of adaptation. The salt water species of the A. gambiae complex, A. melas, was found to be tolerant to waters with very low salinity. On the other hand, A. gambiae s.s. was found to support relatively high salinity rates. Both specimens live together the whole year round but their frequencies vary with the inundation of the lake. During inundation the salt rate decreases and A. melas eventually disappears. Transmission is low, seasonal and short on the lake. It is perceptible between March and August. The inoculation rate (11 infected bites per man/year) is lower than what we have observed in other lagoon areas of Benin, or even in the city of Cotonou (33 infected bites per man/year). The low malaria transmission on the lake is probably due to the presence of an important population of A. melas with low infection rates and the widespread use of bed nets.
在一项纵向研究中，我们观察了在一个建在微咸湖旁的村庄中，两种传播疟疾的按蚊种群密度的波动情况。这两种冈比亚按蚊复合体物种分别是梅拉斯按蚊和冈比亚按蚊指名亚种。前者数量最多（占88%）。微咸湖生态系统为这两个物种提供了适应的可能性。冈比亚按蚊复合体中的咸水物种梅拉斯按蚊被发现能耐受盐度极低的水域。另一方面，冈比亚按蚊指名亚种则能适应相对较高的盐度。这两个物种全年都生活在一起，但它们的数量随湖水的淹没情况而变化。在湖水淹没期间，盐度降低，梅拉斯按蚊最终消失。该湖泊地区的疟疾传播率低、具有季节性且持续时间短。在3月至8月间可以察觉到疟疾传播。接种率（每人每年11次感染叮咬）低于我们在贝宁其他泻湖地区甚至科托努市所观察到的情况（每人每年33次感染叮咬）。该湖泊地区疟疾传播率低可能是由于存在大量感染率低的梅拉斯按蚊以及蚊帐的广泛使用。
