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（1996年为45万例）中，99%发生在亚马逊地区。1995年和1996年，巴西亚马逊河北部的罗赖马州获得了巴西年度寄生虫指数最高的殊荣。在罗赖马，主要疟蚊病媒尚未查明或认定是何种病媒，而且对种群结构、季节波动或繁殖地点偏好几乎一无所知。这些基本的生物学信息最终将用于更有效地控制当地疟疾传播。本项目拟利用分子技术，准确识别主要疟疾媒介，确定传播责任人，并对阿氏按蚊（Anopheles albitarsis complex）和阿氏按蚊（Anopheles albitarsis）的种群结构和繁殖地进行研究。这两种物种都出现在罗赖马州的拟议研究地点。达林按蚊是拉丁美洲最有效的疟疾病媒，但在美洲的物种。albitasis复合体特别是marajoara)在巴西附近的Amapa州被认为是重要的地方病媒。这些种属于新热带亚属Nyssorhynchus。将在罗赖马州博阿维斯塔附近的两个疟疾地方病点（一个农村，一个城市）每月采集成蚊和幼虫。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鉴定。隐种的分子鉴定将与ELISA的寄生虫检测相结合。微卫星引物(最近开发的An。Darlingi)将用于比较两个地方性收集点幼虫繁殖地和成虫收集地的种群结构。

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.