MOLECULAR ANALYSIS OF MALARIA VECTORS IN RORAIMA, BRAZIL

在全球范围内，疟疾是最重要的寄生虫病，每年影响3-5亿人。在巴西报告的疟疾病例中(1996年为45万例)，99%发生在亚马逊地区。1995年和1996年，巴西亚马逊河流域北部的罗莱马州有一个令人怀疑的区别，那就是巴西的年度寄生虫指数最高。在罗莱马，主要的按蚊媒介尚未确定或被牵连，而且几乎对种群结构、季节波动或滋生地点偏好一无所知。这些基本的生物学信息最终将被用于更有效地控制当地疟疾传播。利用分子技术，该项目建议准确识别主要的疟疾媒介，指认那些传播疟疾的人，并检查阿尔比塔按蚊复合体和按蚊物种的种群结构和繁殖地。达林吉，这两个都出现在罗莱马州的拟议研究地点。达林伊按蚊是拉丁美洲最有效的疟疾媒介，但也是该地区的物种。钠长石复合体(An.尤其是Marajoara)在巴西附近的Amapa州被牵连为重要的当地媒介。这些种属于新热带亚属Nyssorhynchus。每月将在罗莱马州Boa Vista附近的两个疟疾流行地点(一个在农村，一个在城市)收集成虫和幼虫。成虫和幼虫将使用形态键(可以准确区分物种)或新开发的分子探针进行识别。对隐蔽物种的分子鉴定将与ELISA的寄生虫检测相结合。微卫星引物(最近为An.将用于比较两个地方性收集点的幼虫繁殖点和成虫收集点的种群结构。

Globally, malaria is the most important parasitic disease, affecting 300-500 million persons annually. Of the malaria cases (450,000 in 1996) reported in Brazil, 99 percent occurred in the Amazon region. In both 1995 and 1996 Roraima State in northern Amazonian Brazil had the dubious distinction of having the highest annual parasitic index (IPA) in Brazil. In Roraima, the principal anopheline malaria vectors have not yet been identified or incriminated, and virtually nothing is known about population structure, seasonal fluctuations or breeding site preferences. This basic biological information will ultimately be used to more effectively control local malaria transmission. Using molecular techniques, this project proposes to accurately identify the main malaria vectors, incriminate those responsible for transmission, and examine population structure and breeding sites within species of the Anopheles albitarsis complex and An. darlingi, both of which are present in the proposed study sites in Roraima State. Anopheles darlingi is the most efficient malaria vector in Latin America but species in the An. albitarsis complex (An. marajoara, in particular) have been implicated as important local vectors in nearby Amapa state in Brazil. These species are in the neotropical subgenus Nyssorhynchus. Adult and larval mosquitoes will be collected monthly in two endemic malaria sites (one rural, and one urban) near Boa Vista in Roraima State. Adults and larvae will be identified using either morphological keys (where they can accurately distinguish species) or newly developed molecular probes. Molecular identification of cryptic species will be coupled with parasite detection of ELISA. Microsatellites primers (recently developed for An. darlingi) will be used to compare population structure in larval breeding sites and adult collections in each of the two endemic collection sites.