Entomology Department, Military Institute of Hygiene and Epidemiology, Hanoi, Vietnam.
Malar J. 2010 Sep 16;9:259. doi: 10.1186/1475-2875-9-259.
Malaria is still prevalent in rural communities of central Vietnam even though, due to deforestation, the primary vector Anopheles dirus is uncommon. In these situations little is known about the secondary vectors which are responsible for maintaining transmission. Basic information on the identification of the species in these rural communities is required so that transmission parameters, such as ecology, behaviour and vectorial status can be assigned to the appropriate species.
In two rural villages--Khe Ngang and Hang Chuon--in Truong Xuan Commune, Quang Binh Province, north central Vietnam, a series of longitudinal entomological surveys were conducted during the wet and dry seasons from 2003-2007. In these surveys anopheline mosquitoes were collected in human landing catches, paired human and animal bait collections, and from larval surveys. Specimens belonging to species complexes were identified by PCR and sequence analysis, incrimination of vectors was by detection of circumsporozoite protein using an enzyme-linked immunosorbent assay.
Over 80% of the anopheline fauna was made up of Anopheles sinensis, Anopheles aconitus, Anopheles harrisoni, Anopheles maculatus, Anopheles sawadwongporni, and Anopheles philippinensis. PCR and sequence analysis resolved identification issues in the Funestus Group, Maculatus Group, Hyrcanus Group and Dirus Complex. Most species were zoophilic and while all species could be collected biting humans significantly higher densities were attracted to cattle and buffalo. Anopheles dirus was the most anthropophilic species but was uncommon making up only 1.24% of all anophelines collected. Anopheles sinensis, An. aconitus, An. harrisoni, An. maculatus, An. sawadwongporni, Anopheles peditaeniatus and An. philippinensis were all found positive for circumsporozoite protein. Heterogeneity in oviposition site preference between species enabled vector densities to be high in both the wet and dry seasons allowing for year round transmission.
In rural communities in north central Vietnam, malaria transmission was maintained by a number of anopheline species which though collected feeding on humans were predominantly zoophilic, this behaviour allows for low level but persistent malaria transmission. The important animal baits--cattle and buffalo--were kept in the village and barrier spraying around these animals may be more effective at reducing vector densities and longevity than the currently used indoor residual spraying.
尽管由于森林砍伐，主要媒介按蚊属库蚊已不常见，但疟疾在越南北中部的农村社区仍很普遍。在这些情况下，人们对负责维持传播的次要媒介知之甚少。需要了解这些农村社区中物种的基本信息，以便将生态、行为和媒介状况等传播参数分配给相应的物种。
在越南北中部广平县春川县的 Khe Ngang 和 Hang Chuon 两个农村村庄，于 2003-2007 年的雨季和旱季进行了一系列纵向昆虫学调查。在这些调查中，使用人体降落捕获法、人和动物诱饵配对收集法和幼虫调查法收集按蚊。通过 PCR 和序列分析鉴定属于种复合体的标本，通过酶联免疫吸附试验检测环子孢子蛋白来确定媒介。
超过 80%的按蚊区系由中华按蚊、库蚊、哈氏按蚊、致倦库蚊、Sawadwongporni 按蚊和菲律宾按蚊组成。PCR 和序列分析解决了 Funestus 组、Maculatus 组、Hyrcanus 组和 Dirus 复合体的鉴定问题。大多数物种为嗜血性，虽然所有物种都可以叮咬人类，但对牛和水牛的吸引力更高。按蚊属库蚊是最嗜人血的物种，但很罕见，仅占所有采集的按蚊的 1.24%。中华按蚊、库蚊、哈氏按蚊、致倦库蚊、Sawadwongporni 按蚊、嗜人按蚊和菲律宾按蚊均检测到环子孢子蛋白呈阳性。种间产卵地点偏好的异质性使媒介密度在雨季和旱季都很高，从而实现全年传播。
在越南北中部的农村社区，疟疾传播由多种按蚊种维持，尽管这些按蚊种采集时以人类为食，但主要为嗜血性，这种行为允许低水平但持续的疟疾传播。重要的动物诱饵——牛和水牛——被养在村里，围绕这些动物进行的屏障喷洒可能比目前使用的室内滞留喷洒更能有效降低媒介密度和寿命。
