Unité d'entomologie médicale, Institut Pasteur de Dakar, Dakar, Sénégal.
Parasit Vectors. 2012 Dec 7;5:286. doi: 10.1186/1756-3305-5-286.
Although adult mosquito vectors of sylvatic arbovirus [yellow fever (YFV), dengue-2 (DENV-2) and chikungunya (CHIKV)] have been studied for the past 40 years in southeastern Senegal, data are still lacking on the ecology of larval mosquitoes in this area. In this study, we investigated the larval habitats of mosquitoes and characterized their seasonal and spatial dynamics in arbovirus foci.
We searched for wet microhabitats, classified in 9 categories, in five land cover classes (agriculture, forest, savannah, barren and village) from June, 2010 to January, 2011. Mosquito immatures were sampled monthly in up to 30 microhabitats of each category per land cover and bred until adult stage for determination.
No wet microhabitats were found in the agricultural sites; in the remaining land covers immature stages of 35 mosquito species in 7 genera were sampled from 9 microhabitats (tree holes, fresh fruit husks, decaying fruit husks, puddles, bamboo holes, discarded containers, tires, rock holes and storage containers). The most abundant species was Aedes aegypti formosus, representing 30.2% of the collections, followed by 12 species, representing each more than 1% of the total, among them the arbovirus vectors Ae. vittatus (7.9%), Ae. luteocephalus (5.7%), Ae. taylori (5.0%), and Ae. furcifer (1.3%). Aedes aegypti, Cx. nebulosus, Cx. perfuscus, Cx. tritaeniorhynchus, Er. chrysogster and Ae. vittatus were the only common species collected from all land covers. Aedes furcifer and Ae. taylori were collected in fresh fruit husks and tree holes. Species richness and dominance varied significantly in land covers and microhabitats. Positive associations were found mainly between Ae. furcifer, Ae. taylori and Ae. luteocephalus. A high proportion of potential enzootic vectors that are not anthropophilic were found in the larval mosquito fauna.
In southeastern Senegal, Ae. furcifer and Ae. taylori larvae showed a more limited distribution among both land cover and microhabitat types than the other common species. Uniquely among vector species, Ae. aegypti formosus larvae occurred at the highest frequency in villages. Finally, a high proportion of the potential non-anthropophilic vectors were represented in the larval mosquito fauna, suggesting the existence of unidentified sylvatic arbovirus cycles in southeastern Senegal.
尽管在过去的 40 年中，塞内加尔东南部已经对丛林黄热病（YFV）、登革热 2 型（DENV-2）和基孔肯雅热（CHIKV）等丛林蚊媒进行了研究，但关于该地区幼虫蚊的生态学数据仍存在不足。在这项研究中，我们调查了蚊子的幼虫栖息地，并描述了在虫媒病毒病热点地区幼虫的季节性和空间动态。
我们从 2010 年 6 月至 2011 年 1 月，在农业、森林、热带稀树草原、荒地和村庄 5 种土地覆盖类型中，搜索了 9 个类别的潮湿微生境。每月在每个土地覆盖类型的每个类别中最多采集 30 个微生境中的蚊虫幼虫，并进行繁殖直至成虫，以便进行鉴定。
在农业区没有发现潮湿的微生境；在其余的土地覆盖区，从 9 个微生境（树洞、新鲜水果皮、腐烂水果皮、水坑、竹筒、废弃容器、轮胎、石缝和储存容器）中采集到了 7 属 35 种蚊虫的幼虫。最丰富的物种是埃及伊蚊，占采集总数的 30.2%，其次是 12 种，每种都占总数的 1%以上，其中包括虫媒病毒载体埃及伊蚊（7.9%）、白纹伊蚊（5.7%）、Ae. taylori（5.0%）和 Ae. furcifer（1.3%）。埃及伊蚊、库蚊、淡色库蚊、三带喙库蚊、致倦库蚊和埃及伊蚊是唯一从所有土地覆盖区采集到的共同物种。埃及伊蚊、白纹伊蚊、淡色库蚊、三带喙库蚊、致倦库蚊和埃及伊蚊在所有土地覆盖区都有发现。埃及伊蚊和 Ae. taylori 是在新鲜水果皮和树洞中采集到的。物种丰富度和优势度在土地覆盖和微生境中差异显著。主要发现了 Ae. furcifer、Ae. taylori 和 Ae. luteocephalus 之间的正关联。在幼虫蚊媒动物群中发现了大量潜在的非嗜人血的地方性媒介。
在塞内加尔东南部，埃及伊蚊和 Ae. taylori 幼虫在土地覆盖类型和微生境类型中的分布比其他常见物种更为有限。与其他媒介物种不同，埃及伊蚊在村庄中的出现频率最高。最后，幼虫蚊媒动物群中代表了大量潜在的非嗜人血的媒介，表明在塞内加尔东南部可能存在未被识别的丛林虫媒病毒循环。
