Wednesday, November 18, 2009

Male infertility

How does male sterility combat malaria? When mosquitoes are sterile, they devastate the entire mosquito population. Called the Sterile Insect Technique (SIT), "the release of sexually sterile male insects to wipe out a pest population" is suggested as a "solution to the problem of malaria in Africa" (BioMed).

Malaria "control in sub-Saharan Africa, where 90 percent of the 300 to 500 million malaria cases and one to three million deaths occur from malaria each year, still depends on only two technologies for vector intervention: indoor residual spraying and insecticide-treated bed nets" (Klassen). Overtime mosquitoes become resistant to pesticides and insect populations bounce back from elimination efforts. According to researcher, Mark Benedict, "In the context of elimination, SIT could play a unique role. As part of an area-wide integrated pest management programme, the SIT may be able to minimize problems due to insecticide resistance to antimalarial drugs" (BioMed).

This technique "involves the generation of 'sterile' male mosquitoes, which are incapable of producing offspring despite being sexually active. Because female mosquitoes only mate once during their lifetimes, a single mating with a sterile male can ensure that she will never breed" This leads to an increasing reduction in the population over time, in contrast to insecticides, which kill a certain fraction of the insect population" (BioMed).

Considerable "research and development on the suppression of mosquitoes with the sterile insect technique (SIT) was conducted from the mid-1950s to the mid-1970s"; however, "nearly all of the scientists who pioneered this approach have retired and several of the greatest have died." The resurgence of this idea is due in part to "new technologies" that are "available to support area-wide integrated pest management (AW-IPM) programmes" (Klassen).

If implemented in Africa, the sterile insect technique when combined with other measures could effectively eliminate the malaria-carrying mosquito population in Africa.

For an overview of the history of malaria and the SIT project, please read the study's introduction in the malaria journal:

BioMed Central. "Are Sterile Mosquitoes the Answer to Malaria Elimination?." ScienceDaily 17 November 2009. 18 November 2009 .
Klassen, Wauldemar. "Introduction: development of the sterile insect technique for African malaria vectors". Homestead, Florida. 16 November 2009.

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