Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe Street, Room E5545, Baltimore, Maryland 21205, USA.
Malar J. 2013 May 31;12:178. doi: 10.1186/1475-2875-12-178.
Plasmodium vivax and Plasmodium falciparum cause a significant illness burden in Peru. Anopheline indices for populated communities in the peri-Iquitos region of Loreto have been reported to be remarkably low, with entomological inoculation rates (EIR) estimated at one to 30 infective bites per year based on a few studies in close proximity to the urban centre of Iquitos and surrounding deforested areas. Local reports suggest that a large number of the reported cases are contracted outside of populated communities in undeveloped riverine areas frequented by loggers and fishermen.
To better understand vectorial capacity in suspected high malaria transmission zones in a rural district near Iquitos, Peru, mosquito collections were conducted at different points in the seasonality of malaria transmission in 21 sites frequented by occupational labourers. Prevalence of Plasmodium spp in vectors was determined by circumsporozoite protein ELISA on individual mosquitoes. Slide surveillance was performed for humans encountered in the zone.
In total, of 8,365 adult female mosquitoes examined, 98.5% were identified as Anopheles darlingi and 117 (1.4%) tested positive for sporozoites (P. falciparum, P. vivax VK210 or P. vivax VK247). Measured human biting rates at these sites ranged from 0.102 to 41.13 bites per person per hour, with EIR values as high as 5.3 infective bites per person per night. Six percent of the 284 blood films were positive for P. vivax or P. falciparum; however, 88% of the individuals found to be positive were asymptomatic at the time of sampling.
The results of this study provide key missing indices of prominent spatial and temporal heterogeneity of vectorial capacity in the Amazon Basin of Peru. The identification of a target human subpopulation as a principal reservoir and dispersion source of Plasmodium species has important implications for vaccine development and the delivery of effective targeted malaria control strategies.
在秘鲁，间日疟原虫和恶性疟原虫会导致严重的疾病负担。据报道，伊基托斯周边地区的人口聚居社区的按蚊指数非常低，根据伊基托斯市中心及周边森林砍伐地区的几项研究估计，昆虫接种率（EIR）估计为每年每 1 至 30 次感染性叮咬。当地报告显示，大量报告的病例发生在人口聚居社区以外的未开发的河流地区，这些地区经常有伐木工和渔民出没。
为了更好地了解秘鲁伊基托斯附近一个农村地区疑似高疟疾传播区的媒介传播能力，在疟疾传播季节性的不同时间点，在 21 个人口密集的职业工人劳动地点进行了蚊子采集。通过环子孢子蛋白 ELISA 检测个体蚊子中疟原虫的存在来确定媒介中的疟原虫感染率。对该区域遇到的人类进行了镜检。
总共检查了 8365 只成年雌性蚊子，其中 98.5%被鉴定为趋性按蚊，117 只（1.4%）检测出孢子虫阳性（恶性疟原虫、间日疟原虫 VK210 或间日疟原虫 VK247）。这些地点的人类叮咬率在 0.102 至 41.13 人/小时之间，EIR 值高达 5.3 人/夜感染性叮咬。284 张血片中，有 6%为间日疟原虫或恶性疟原虫阳性；然而，在采样时，88%的阳性个体无症状。
本研究结果提供了秘鲁亚马逊流域重要的空间和时间媒介传播能力异质性缺失指标。确定目标人群作为疟原虫物种的主要储存库和扩散源，对疫苗开发和有效有针对性的疟疾控制策略的实施具有重要意义。
