UNLABELLED: 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. METHODS: 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. RESULTS: 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.
UNLABELLED: 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. METHODS: 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. RESULTS: 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.
Authors: Hui Vern Wong; Indra Vythilingam; Wan Yusof Wan Sulaiman; Aleksei Lulla; Andres Merits; Yoke Fun Chan; I-Ching Sam Journal: Am J Trop Med Hyg Date: 2015-11-23 Impact factor: 2.345
Authors: Claire J Heath; Elysse N Grossi-Soyster; Bryson A Ndenga; Francis M Mutuku; Malaya K Sahoo; Harun N Ngugi; Joel O Mbakaya; Peter Siema; Uriel Kitron; Nayer Zahiri; Jimmy Hortion; Jesse J Waggoner; Charles H King; Benjamin A Pinsky; A Desiree LaBeaud Journal: PLoS Negl Trop Dis Date: 2020-06-19
Authors: Amy Krystosik; Gathenji Njoroge; Lorriane Odhiambo; Jenna E Forsyth; Francis Mutuku; A Desiree LaBeaud Journal: Front Public Health Date: 2020-01-17
Authors: Elaine Y Y Huang; Annette Y P Wong; Ivy H T Lee; Zhe Qu; Ho Yin Yip; Chi-Wah Leung; Shuk-May Yin; Jerome H L Hui Journal: Parasit Vectors Date: 2020-07-20 Impact factor: 3.876
Authors: Julie-Anne A Tangena; Sébastien Marcombe; Phoutmany Thammavong; Somsanith Chonephetsarath; Boudsady Somphong; Kouxiong Sayteng; Marc Grandadam; Ian W Sutherland; Steve W Lindsay; Paul T Brey Journal: PLoS One Date: 2018-10-25 Impact factor: 3.240