Dengue control


There is an urgent need to develop vector control tools for sustained control of Aedes populations in endemic communities.

Some promising new dengue vector control tools are the subject of research and are currently being field-tested for their use as public health interventions.

Some research areas are:

Insecticide-treated materials

Insecticide-treated materials (ITMs) consist of long-lasting insecticidal nets, curtains and wall hangings. Bednets have proved highly effective in preventing diseases transmitted by nocturnally active mosquitoes.

Insecticide-treated window curtains and sheet covers can also reduce dengue vector densities and transmission.

In studies in Mexico and Venezuela, ITMs (particularly curtains) were well accepted by the communities as their efficacy was reinforced by the reduction of other biting insects as well as cockroaches, houseflies and other pests. Window curtains, screens, and doorway or wardrobe curtains, etc. all appear to have promising results in different settings.

If the application of these interventions is shown to be efficacious, cost-effective and sustainable; it may offer additional prospects for dengue vector control in the home, workplace, schools, hospitals and other locations, and allow for the selection of the most appropriate ITMs by the communities that will use them.

Lethal ovitraps

Ovitraps or oviposition traps collect the eggs laid by the mosquitoes which develop into larva, pupa and adult mosquitoes. Ovitraps are often used for surveillance of Aedes vectors can be modified to render it lethal to immature or adult populations of Ae. aegypti.

Lethal ovitraps (which incorporate an insecticide on the oviposition substrate), autocidal ovitraps (which allow oviposition but prevent adult emergence), and sticky ovitraps (which trap the mosquito when it lands) have been used on a limited basis. Studies have shown that population densities can be reduced with sufficiently large numbers of frequently-serviced traps.

Life expectancy of the vector may also potentially be shortened, thus reducing the number of vectors that become infective.

Genetically-modified mosquitoes

There are two methods of reducing disease transmission using genetics:

  • Population suppression: reduce mosquito population such that it would not be able to sustain pathogen transmission. This includes sterility, reduced adult longevity, or decrease larva/pupa survival.
  • Population replacement: Reduce inherent ability to transmit the pathogen. Mating will alter the genetic pool of the wild population.

The effects of the genetic modification can be self-limiting or self-sustaining (fitness cost and drive). Self-limiting technologies are not capable of persisting in the environment and in the wild genome pool. Self-sustaining genetic transfer will be able transfer genes across generations and is dealt with caution to avoid any other issues.

©RBP/Research on Aedes aegypti in laboratory - Fiocruz, June 2006