Russell Tanya L, Burkot Thomas R, Bugoro Hugo, Apairamo Allan, Beebe Nigel W, Chow Weng K, Cooper Robert D, Collins Frank H, Lobo Neil F
Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, 4870, Australia.
National Vector Borne Disease Control Programme, Ministry of Health, Honiara, Solomon Islands.
Malar J. 2016 Mar 15;15:164. doi: 10.1186/s12936-016-1196-7.
There is an urgent need for vector control tools to supplement long-lasting insecticidal nets (LLINs) and indoor residual spraying; particularly in the Solomon Islands where the primary vector, Anopheles farauti, is highly anthropophagic and feeds mainly outdoors and early in the evening. Currently, the only supplementary tool recommended by the World Health Organization is larval source management (LSM). The feasibility and potential effectiveness of LSM requires information on the distribution of anophelines, the productivity of larval habitats and the potential impacts of larval control on adult fitness.
The distribution of anophelines in Central and Western Provinces in the Solomon Islands was mapped from cross-sectional larval habitat surveys. The composition and micro-distribution of larval instars within a large permanent river-mouth lagoon was examined with a longitudinal survey. Density-dependent regulation of An. farauti larvae was investigated by longitudinally following the development and survival of different densities of first instars in floating cages in a river-mouth lagoon.
Five anopheline species were molecularly identified from a range of fresh and brackish water habitats: An. farauti s.s., An. hinesorum, An. lungae, An. nataliae and An. solomonis. The most common habitats used by the primary malaria vector, An. farauti, were coastal lagoons and swamps. In the detailed study of lagoon micro-productivity, An. farauti was non-uniformly distributed with highest densities found at collections sites most proximal and distal to the mouth of the lagoon. The survival of An. farauti larvae was more than twofold lower when larvae were held at the highest experimental density (1 larva per 3.8 cm(2)) when compared with the lowest density (1 larva per 38 cm(2)).
The only documented major malaria vector collected in larval surveys in both Central and Western Provinces was An. farauti. Lagoons and swamps, the most common, largest and (potentially) most productive larval sites of this malaria vector, were "few, fixed and findable" and theoretically, therefore, amenable to successful LSM. However, the immense scale and complexity of these ecosystems in which An. farauti larvae are found raises questions regarding the ability to effectively control the larvae, as incomplete larviciding could trigger density dependent effects resulting in increased larval survivorship. While LSM has the potential to significantly contribute to malaria control of this early and outdoor biting vector, more information on the distribution of larvae within these extensive habitats is required to maximize the effectiveness of LSM.
迫切需要病媒控制工具来补充长效驱虫蚊帐（LLINs）和室内滞留喷洒；特别是在所罗门群岛，主要病媒法氏按蚊高度嗜人，主要在户外和傍晚早期觅食。目前，世界卫生组织推荐的唯一补充工具是幼虫源管理（LSM）。LSM的可行性和潜在有效性需要有关按蚊分布、幼虫栖息地生产力以及幼虫控制对成虫健康的潜在影响的信息。
通过横断面幼虫栖息地调查绘制了所罗门群岛中部和西部省份按蚊的分布图。通过纵向调查研究了一个大型永久性河口泻湖内幼虫龄期的组成和微分布。通过纵向跟踪河口泻湖浮动网箱中不同密度一龄幼虫的发育和存活情况，研究了法氏按蚊幼虫的密度依赖性调节。
从一系列淡水和微咸水栖息地中分子鉴定出五种按蚊：法氏按蚊指名亚种、欣氏按蚊、伦氏按蚊、纳塔尔按蚊和所罗门按蚊。主要疟疾媒介法氏按蚊最常见的栖息地是沿海泻湖和沼泽。在对泻湖微生产力的详细研究中，法氏按蚊分布不均匀，在泻湖口最近端和最远端的采集点密度最高。与最低密度（每38平方厘米1只幼虫）相比，当幼虫饲养在最高实验密度（每3.8平方厘米1只幼虫）时，法氏按蚊幼虫的存活率降低了两倍多。
在中部和西部省份的幼虫调查中收集到的唯一有记录的主要疟疾媒介是法氏按蚊。泻湖和沼泽是这种疟疾媒介最常见、最大且（可能）生产力最高的幼虫栖息地，数量“稀少、固定且可找到”，因此从理论上讲适合成功进行幼虫源管理。然而，发现法氏按蚊幼虫的这些生态系统规模巨大且复杂，这引发了关于有效控制幼虫能力的问题，因为不完全杀灭幼虫可能引发密度依赖性效应，导致幼虫存活率增加。虽然幼虫源管理有可能对这种早期和户外叮咬媒介的疟疾控制做出重大贡献，但需要更多关于这些广泛栖息地内幼虫分布的信息，以最大限度地提高幼虫源管理的有效性。
