According to World Health Organization, preventing or reducing dengue virus transmission depends entirely the control of the mosquito vectors or interruption of human–vector contact.
In essence, the prevention and control activity for dengue fever is centred on the control of the transmitting vector or agent i.e. the mosquito. Past research in Fiji and various published report identified Aedes aegypti mosquitoes as the most effective vector for dengue fever. The mosquito prefers to inhabit close to household and immediate vicinity of its food source (blood meal), as well as other settings (such as schools, hospitals and workplaces). Therefore, the dengue, fever Interventions are focused on eliminating or at least reducing the population of mosquitoes around areas where humans habitat.
The World Health Organization recommends an integrated vector management (IVM) as the strategic approach for vector control. IVM is defined as “a rational decision-making process for the optimal use of resources for vector control”. The Integrated Vector Management (IVM) considers five key elements in the management process, namely:
- Advocacy, social mobilization and legislation
- Collaboration within the health sector and with other sectors
- Integrated approach to disease control
- Evidence-based decision-making
According to a recent review on the Vector Control initiatives by a WHO Consultant (Unpublished 2014), Fiji has a long history of dealing with dengue (since 1885) and has a leading dengue vector control program in the Melanesia and Pacific region. Whilst the consultant noted that there is a high level of knowledge and awareness of dengue amongst the health leadership and staff, there is scope to provide additional resources to increase mobility and technical capacity of the teams.
Despite limitations, the overall aim for vector control has been to eliminate all potential breeding habits of mosquitoes through effective vector reduction campaign in the high risk urban and rural areas within the operational health division’s placing greater emphasis on source reduction through basic environmental health approaches and community mobilization. This is implemented through:
- Vector reduction campaign via clean-up of compounds / backyard , overgrowth in vacant lots and blocked drains
- Cartage of refuse in dengue sensitive and high risk areas within the rural areas
- Mobilization of community to sustain clean and vector free environment
Intersectoral collaboration through a National Dengue Clean-Up Initiative which is places emphasis on destroying mosquito breeding in tyres, drums and other receptacles that can retain water.
Apart from source reduction, vector control can be achieved through good water supply and storage measures (mosquito proofing water storage containers), good solid waste management practices (ensuring that potential water retaining receptacles are properly disposed), and through the use of chemical controls. Chemical controls are usually done through spraying which ideally targets adult mosquitoes and through larviciding which targets immature mosquito larvae. In addition, entomological monitoring and surveillance through the monitoring of vector populations through larval and adult mosquito monitoring coupled with timely feedbacks are essential for dengue prevention and control.
A final tool that is available for effective dengue control is through the use of legislative advocacy and implementation of legislative authority. Simply put, imposing of fines to persons who harbour or breed mosquitoes. The limitations to such an approach are the long awaited court processes and associated court costs to resolve an eminent threat.
Finally, dengue Fever is preventable, but no prevention is 100% effective. Some of the best means of prevention starts with an individual mindset towards self-protection. Some of these prevention measures include minimizing mosquito bites, avoiding mosquito-prone areas and using of repellents. Apart from these, source reduction through elimination of mosquito breeding sites is the best course in prevention dengue.
It is only through the combination of these efforts successful dengue control can be achieved.
1. Dengue: guidelines for diagnosis, treatment, prevention and control — New edition (2009), World Health Organization.