Rohani A, Aidil Azahary A R, Malinda M, Zurainee M N, Rozilawati H, Wan Najdah W M A, Lee H L
Medical Entomology Unit, Infectious Disease Research Centre, Institute for Medical Research, Kuala Lumpur, Malaysia.
J Vector Borne Dis. 2014 Dec;51(4):327-32.
BACKGROUND & OBJECTIVESI: Transovarial transmission of dengue virus in the Aedes vectors is now a well-documented phenomenon reported from many parts of the endemic areas in the world, which played an important role in initiating and maintaining the outbreak in human populations. This study investigated the factors affecting breeding habitats and the relationship with transovarial dengue virus in larvae of Aedes aegypti and Ae. albopictus.
Larval surveillance was conducted in dengue outbreak areas in Malaysia from 2008 until 2009. Sampling was carried out based on habitat type, water condition (substrate type), canopy coverage, temperature and pH at breeding habitats. RT-PCR was performed to detect presence of transovarial dengue virus in larvae collected in the study areas.
A total of 789 breeding habitats were identified during this study and the majority of these breeding sites were plastic containers (57.46%). Aedes albopictus dominated most of the water condition surveyed, while Ae. aegypti indicated preference toward habitats with clear water. Aedes aegypti was selective in selecting ovipositional sites compared to Ae. albopictus where shaded areas were shown to be the most preferred. From a total of 363 mosquito larvae pools, 23 (6.3%) pools were positive for dengue virus where 18 of them were from Ae. albopictus and five were from Ae. aegypti mosquito larvae pools.
INTERPRETATION & CONCLUSION: This study indicated the presence of transovarial transmission of dengue virus in immature Ae. aegypti and Ae. albopictus in the field. This study also showed that combination of water conditions, canopy coverage, temperature and pH of breeding habitats were the factors affecting the larval population. The study suggested that larval survey programme could serve as a tool not only to monitor the local dengue vector distribution but also to provide objective information for taking appropriate action by the community against dengue vectors.
背景与目的：登革病毒在伊蚊媒介中的经卵传播现已成为世界上许多流行地区报道的一种有充分记录的现象，它在引发和维持人类群体中的疫情爆发方面发挥了重要作用。本研究调查了影响埃及伊蚊和白纹伊蚊幼虫繁殖栖息地的因素以及与经卵传播登革病毒的关系。
2008年至2009年在马来西亚登革热疫情爆发地区进行幼虫监测。根据繁殖栖息地的类型、水的状况（底物类型）、树冠覆盖率、温度和pH值进行采样。对在研究区域收集的幼虫进行逆转录聚合酶链反应（RT-PCR）以检测经卵传播登革病毒的存在。
在本研究期间共确定了789个繁殖栖息地，其中大多数繁殖地点是塑料容器（57.46%）。在调查的大多数水的状况中白纹伊蚊占主导，而埃及伊蚊则表现出对清水栖息地的偏好。与白纹伊蚊相比，埃及伊蚊在选择产卵地点时具有选择性，其中阴凉区域是最受青睐的。在总共363个蚊虫幼虫样本中，23个（6.3%）样本登革病毒呈阳性，其中18个来自白纹伊蚊，5个来自埃及伊蚊幼虫样本。
本研究表明在野外未成熟的埃及伊蚊和白纹伊蚊中存在登革病毒的经卵传播。本研究还表明繁殖栖息地的水的状况、树冠覆盖率、温度和pH值的组合是影响幼虫数量的因素。该研究表明幼虫调查计划不仅可以作为监测当地登革热媒介分布的工具，还可以为社区采取针对登革热媒介的适当行动提供客观信息。
