Mweya Clement N
Mbeya College of Health and Allied Sciences, University of Dar es Salaam, Mbeya, Tanzania.
Trop Med Int Health. 2025 Sep 2. doi: 10.1111/tmi.70032.
This study aimed to assess the prevalence of dengue virus (DENV) infection in Aedes aegypti mosquitoes and evaluate associated ecological and environmental factors in three inland districts (Bahi, Kyela, Ngorongoro) with distinct agro-ecological characteristics and no prior dengue outbreak reports.
A cross-sectional entomological study was conducted during the wet (April-June 2022) and dry (October-November 2022) seasons. Adult mosquitoes were collected indoors and outdoors using battery-powered aspirators, and immature stages were sampled from natural and artificial water containers. Mosquito pools were screened for DENV RNA using RT-qPCR.
A total of 6459 Ae. aegypti mosquitoes were sampled (54% females). DENV RNA was detected in 0.6% (4/631) of the tested pools: one from Bahi and three from Kyela. No infections were detected in Ngorongoro. High mosquito density was observed in Kyela, particularly in paddy plantations and rice farms. Among DENV-positive pools, 100% (4/4) were collected near vegetation, suggesting that outdoor habitats are high-risk sites. The minimum infection rate was 0.6 (95% CI: 0.2-1.6) per 1000 mosquitoes.
This study confirms silent DENV circulation in Ae. aegypti populations in Tanzanian regions without prior epidemic reports. The detection of DENV in mosquitoes from Bahi and Kyela highlights the risk of future outbreaks and underscores the need for enhanced vector surveillance and integrated control strategies. These findings emphasise the urgency of preemptive public health measures to mitigate dengue spread in Tanzania. Limitations of the study include reliance on RT-qPCR without viral isolation or serotyping and the absence of concurrent human clinical data.
本研究旨在评估埃及伊蚊中登革病毒（DENV）感染的流行情况，并评估三个具有不同农业生态特征且此前无登革热疫情报告的内陆地区（巴希、凯拉、恩戈罗恩戈罗）的相关生态和环境因素。
在雨季（2022年4月至6月）和旱季（2022年10月至11月）进行了一项横断面昆虫学研究。使用电池驱动的吸气器在室内和室外收集成年蚊子，并从天然和人工水容器中采集幼虫阶段样本。使用逆转录定量聚合酶链反应（RT-qPCR）对蚊群进行DENV RNA筛查。
共采集了6459只埃及伊蚊（54%为雌性）。在0.6%（4/631）的检测蚊群中检测到DENV RNA：一只来自巴希，三只来自凯拉。在恩戈罗恩戈罗未检测到感染。在凯拉观察到蚊子密度很高，特别是在稻田和水稻农场。在DENV阳性蚊群中，100%（4/4）是在植被附近采集的，这表明室外栖息地是高风险地点。每1000只蚊子的最低感染率为0.6（95%置信区间：0.2 - 1.6）。
本研究证实了在坦桑尼亚此前无疫情报告的地区，埃及伊蚊种群中存在登革病毒的隐性传播。在来自巴希和凯拉的蚊子中检测到登革病毒，凸显了未来爆发疫情的风险，并强调了加强病媒监测和综合控制策略的必要性。这些发现强调了采取先发制人公共卫生措施以减轻坦桑尼亚登革热传播的紧迫性。该研究的局限性包括依赖RT-qPCR而未进行病毒分离或血清分型，以及缺乏同时期的人类临床数据。
