Pattern of malaria transmission along the Rahad River basin, Eastern Sudan
Pattern of malaria transmission along the Rahad River basin, Eastern Sudan
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DOI：
10.1186/1756-3305-4-109
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发表时间：
2011-06-16
影响因子：
3.2
通讯作者：
Elhassan, Ibrahim M.
中科院分区：
文献类型：
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作者：
Himeidan, Yousif E.;Elzaki, Mervet M.;Elhassan, Ibrahim M.
背景：了解疟疾媒介蚊及其感染力动态对制定干预和控制方案具有重要意义。在苏丹东部的非灌溉和灌溉半干旱地区，疟疾传播模式有所不同。然而，关于季节性河流流域沿着疟疾传播动态的信息很少。这些信息是需要设计有效的病媒控制strategies.Methods：蚊子采样除虫菊喷雾捕捉（PSC）的纵向研究进行了两个村庄（科卡和乌姆萨拉拉）沿着拉哈德河流域2005年12月至2006年10月。用ELISA法检测恶性疟原虫环子孢子（CSP）和人血指数（HBI）。三个季节被认为是和调查代表凉干，热干和雨季分别为11月至2月，3月，6月，7月至10月。用卡方检验比较了不同季节和不同种群间的种群间的CSP。其他昆虫学指标，包括昆虫接种率（EIR）的季节和种群之间的差异，分别采用Tukey-Kramer HSD和学生T检验。安之间的联系。结果：共采集成年雌性按蚊1,402只，其中按蚊占98%。冈比亚复合体;其余为An.红鳍。所有的标本。gambiae复合体经PCR鉴定为An.阿拉伯的。双峰年高峰期。在两个月的时间滞后后，在降雨高峰和拉哈德河的消退之后观察到阿拉伯树密度（科卡r = 0.79，d. f. = 1，P = 0.05; Um Salala，r = 0.88，d.f. = 1，P = 0.02）。只有科卡（P = 0.0009）的CSP在季节之间存在显著差异，其平均值是乌姆萨拉拉（P = 0.0014）的9倍。在干热季节（CSP = 6.25%），在科卡观察到活跃传播，在此期间观察到EIR为0.01 ib/p/n。EIR在雨季达到最高值0.71 ib/p/n，在凉旱季的小高峰期下降到0.18 ib/p/n（P = 0.54）。两个种群的合并年平均EIR为55.48 ib/p/y，通常，个体接受An的感染性叮咬需要大约192.7天。arabiensis.Conclusion:双峰年高峰和在干热季节观察到的活跃传播表明，疟疾传播模式为低度至中度。在降雨高峰和随后拉哈德河流量下降之后，传染性和传播率随着靠近河流而增加。目前的媒介干预措施可以与幼虫控制相结合，并应根据时间和空间的目标制定格式。
Background: Understanding malaria vector mosquitoes and their infectivity dynamics is of importance in setting up intervention and control programmes. Patterns of malaria transmission have been shown to differ between non-irrigated and irrigated semi-arid areas of eastern Sudan. However, very little information is available regarding malaria transmission dynamics along the seasonal river's basin. Such information is required for the design of effective vector control strategies.Methods: A longitudinal study for mosquito sampling using pyrethrum spray catch (PSC) was conducted in two villages (Koka & Um Salala) along the Rahad River basin from December 2005 to October 2006. The Plasmodium falciparum circumsporozoite (CSP) and human blood index (HBI) were detected by ELISA. Three seasons were considered and the surveys represented cool dry, hot dry and rainy seasons were November - February, March June, July - October, respectively. The CSP was compared between the seasons and populations using Chi-square test. The differences between the seasons and the populations in the other entomological indices, including Entomological Inoculation Rates (EIR), were measured using Tukey-Kramer HSD and Student T-test, respectively. The association between An. arabiensis density and monthly total rainfall was examined using regression analysis.Results: A total of 1,402 adult female anopheline mosquitoes were sampled, of which 98% were An. gambiae complex; the rest were An. rufipes. All specimens of An. gambiae complex identified by the PCR were An. arabiensis. Bimodal annual peaks of An. arabiensis densities were observed following the peak of rainfall and recess of the Rahad River after a time-lag of two months (Koka r = 0.79, d.f. = 1, P = 0.05; Um Salala, r = 0.88, d.f. = 1, P = 0.02). The CSP differed significantly among the seasons only in Koka (P = 0.0009) where the mean was nine times higher than in Um Salala (P = 0.0014). Active transmission was observed in Koka during the hot, dry season (CSP = 6.25%) and the EIR was observed to be 0.01 ib/p/n during this time. The EIR peaked to 0.71 ib/p/n during the rainy season and decreased to 0.18 ib/p/n during the minor peak of the cool dry season (P = 0.54). The combined annual average of the EIR for both populations was 55.48 ib/p/y and, typically, it would take approximately 192.7 days for an individual to receive an infective bite from An. arabiensis.Conclusion: The bimodal annual peaks and the active transmission observed during the hot dry season suggested low to moderate perennial malaria transmission pattern. Infectivity and transmission rates increased with proximity to the river following the peak of rainfall and the subsequent recession in the flow of the Rahad River. Current vector interventions can be integrated with larval control and should be formatted in accordance with targeted according to the time and space.