Combating Dengue With Innovative, Paradigm-shift-Strategies: Early Dengue Surveillance in Adult Aedes Mosquitoes

Overview

During dengue outbreaks, the Ministry of Health Malaysia employs various methods to control the spread of disease, including killing the larvae of Aedes mosquitoes, fogging, together with educating and disseminating information about the dengue outbreak, to the community. However, this is too late. Research has shown that when an outbreak has occurred, the viral infection has already spread among the community. Therefore, this current trial aims to educate the public (via questionnaire survey and interactions with the residential managements, mainly), detect dengue-infected mosquitoes, inform the communities of the presence of dengue-infected mosquitoes, followed by approaching and educating them to take precautionary measures before the outbreak happens. Trapping (using gravid oviposition sticky (GOS) traps) and detecting dengue virus non-structural 1 (NS1) antigen (using dengue NS1 kit) in the Aedes mosquitoes will be a more reliable way to alert the community before a potential dengue outbreak in their housing area. The community will receive information of presence of infected mosquitoes and probable dengue infections before dengue cases are reported. This will be an ideal time for clean-ups and for search and destroy activities. With this shift in approach and the use of newer techniques, it is hoped that deaths and epidemics due to dengue will be reduced.

This cluster randomised controlled trial will be conducted to provide evidence on the efficacy of an integrated active vector surveillance and preventive strategy in the community. It aims to demonstrate effectiveness of a new proactive paradigm in reducing dengue epidemics. The main hypotheses are 1) This new paradigm (GOS trap and dengue NS1 kit for detection of dengue in Aedes) will reduce dengue epidemics compared to the usual current vector surveillance/control carried out by the Ministry of Health. 2) Community will be more receptive to this new surveillance activity as they will receive information of dengue transmissions before dengue cases are reported. The study sites at PJU10, Damansara Damai, Petaling Jaya, Selangor, Malaysia are 1. Intervention arm: Harmoni Apartment, Impian Apartment, Park Avenue Condominium, and Suria Shop Apartment 2. Control arm: Permai Apartment, Lestari Apartment, Indah Apartment, and Vista Shop Apartment Activities to be carried out include: A. Questionnaire survey and blood taking for dengue seroprevalence among residents from both arms When people in the community are gathered at an identified, suitable area, the Knowledge, Attitude and Practice (KAP) questionnaires will be distributed for them to answer. After the questionnaire survey, about 3 ml of venous blood would be taken by trained personnel for dengue IgG and IgM serology. B. Placement of the GOS mosquito trap in the intervention arm The GOS mosquito traps will be placed in the intervention arm and serviced weekly. The trapped Aedes mosquitoes would be checked for dengue virus via dengue NS1 rapid diagnostic test kit. The GOS mosquito traps will also be placed randomly in the control arm once per month for entomological survey. C. If a dengue-positive mosquito is found, flyers and banners will be distributed and hung to inform the residents of the presence of dengue transmission in the apartment block/apartment. Alternatively, the residents may also be approached house-to-house or an educational booth set up at strategic locations in the apartment to warn and educate the residents. D. The KAP questionnaire survey will be carried out again 3 months before the completion of the trial in the intervention arm to gauge the communities' perception of this intervention.