A greener vision for vector control: The example of the Singapore dengue control programme

Abstract

Vector-borne diseases are a major cause of morbidity and mortality worldwide. Aedesborne diseases, in particular, including dengue, chikungunya, yellow fever, and Zika, are increasing at an alarming rate due to urbanisation, population movement, weak vector control programmes, and climate change. The World Health Organization calls for strengthening of vector control programmes in line with the Global Vector Control Response (GVCR) strategy, and many vector control programmes are transitioning to this new approach. The Singapore dengue control programme, situated within the country's larger vision of a clean, green, and sustainable environment for the health and well-being of its citizens, provides an excellent example of the GVCR approach in action. Since establishing vector control operations in the 1960s, the Singapore dengue control programme succeeded in reducing the dengue force of infection 10-fold by the 1990s and has maintained it at low levels ever since. Key to this success is consideration of dengue as an environmental disease, with a strong focus on source reduction and other environmental management methods as the dominant vector control strategy. The programme collaborates closely with other government ministries, as well as town councils, communities, the private sector, and academic and research institutions. Community engagement programmes encourage source reduction, and house-to-house inspections accompanied by a strong legislative framework with monetary penalties help to support compliance. Strong vector and epidemiological surveillance means that routine control activities can be heightened to specifically target dengue clusters. Despite its success, the programme continues to innovate to tackle challenges such as climate change, low herd immunity, and manpower constraints. Initiatives include development of novel vector controls such as Wolbachia-infected males and spatiotemporal models for dengue risk assessment. Lessons learnt from the Singapore programme can be applied to other settings, even those less well-resourced than Singapore, for more effective vector control.

Short Report: Adult Aedes abundance and risk of dengue transmission

“…These reports are consolidated through the national surveillance system by the Ministry of Health (Singapore) and transmitted to the NEA for the purpose of implementing disease control activities. Reported dengue infections are linked in space and time in order to determine areas of elevated dengue transmission requiring control activities such as house-to-house inspections to search and destroy mosquito breeding habitats and community engagement to create awareness for dengue and eliciting dengue prevention action [ 24 ]. Such areas are defined as “dengue clusters” and each area is formed when two or more reported infections fall within a 150-meter radius and with illness onset dates within a 14-day period of each other [ 25 ].…”

Effectiveness of Wolbachia-infected mosquito deployments in reducing the incidence of dengue and other Aedes-borne diseases in Niterói, Brazil: A quasi-experimental study

“…Current strategies for dengue control are limited to efforts to suppress immature and adult mosquito numbers, through spraying of insecticides and community campaigns to reduce breeding sites. Even where considerable resources are invested in these activities, sustained suppression of mosquito densities has been elusive, and seasonal outbreaks continue to occur [4,5]. There is a well-recognised need for new, affordable and effective tools for control of dengue and other Aedes-borne arboviruses, including chikungunya and Zika [4,6].…”

Spatio-temporal analysis of the main dengue vector populations in Singapore

“…The low herd immunity [ 15 ], coupled with the tropical climate and highly urbanized environment, poses challenges to the nation’s dengue control program [ 16 ]. As part of Singapore’s vector control program, the National Environment Agency has conducted regular inspections of homes and surrounding areas all year round to remove mosquito-breeding habitats and mobilized the community and stakeholders to minimize instances of stagnant water [ 17 ]. Vector control activities were also ramped up in dengue cluster areas, with space sprays used for adulticiding.…”