Dengue control

Control strategies

©Dr Raman Velayudhan/Breeding of Aedes aegypti mosquitoes in water trapped in a disused tyre

Vector control

Preventing or reducing dengue virus transmission depends entirely in controlling the mosquito vectors or interruption of human–vector contact. WHO promotes the strategic approach known as Integrated Vector Management (IVM) to control mosquito vectors, including those of dengue.

IVM is defined as a 'rational decision-making process for the optimal use of resources for vector control." The aims are to improve efficacy, cost effectiveness, ecological soundness and sustainability (further information on IVM available here).

Transmission control activities should target Ae. aegypti (or any of the other vectors depending on the evidence of transmission) in its immature (egg, larva, and pupa) and adult stages in the household and immediate vicinity. This includes other settings where human–vector contact occurs, such as schools, hospitals and workplaces.

Methods of vector control

Ae. aegypti uses a wide range of confined larval habitats, both man-made and natural.

Some man-made container habitats produce large numbers of adult mosquitoes, whereas others are less productive. Consequently, control efforts should target the habitats that are most productive and hence epidemiologically more important rather than all types of container, especially when there are major resource constraints.

Vector transmission is reduced through the use or combination of these three methods:

Individual and household protection

Self-initiative for source reduction in homes and community. See "Environmental management"

Clothing that minimizes skin exposure during daylight hours when mosquitoes are most active affords some protection from the bites of dengue vectors and is encouraged particularly during outbreaks.

Repellents may be applied to exposed skin or to clothing. The use of repellents must be in strict accordance with label instructions.

Insecticide-treated mosquito nets afford good protection for those who sleep during the day (e.g. infants, the bedridden and night-shift workers).

Where indoor biting occurs, household insecticide aerosol products, mosquito coils or other insecticide vaporizers may also reduce biting activity.

Household fixtures such as window and door screens and air-conditioning can also reduce biting.

Safe use of insecticides

All pesticides are toxic to some degree. Safety precautions for their use – including care in the handling of pesticides, safe work practices for those who apply them, and appropriate field application – should be followed.

WHO Pesticide Evaluation Scheme (WHOPES) has published specific guidelines on use of insecticides, safety procedures, quality control and guidelines for testing.