Monday, February 7, 2011

Malaria Inside and Out

According to a new article in Nature, a recent discovery of a subspecies of mosquito may mean that eradicating malaria could be next to impossible. Malaria kills roughly 710,000 people in Sub-Saharan Africa every year. The disease is caused by the parasite plasmodium falciparum, which is carried most often by the Anopheles gambiae mosquito. Researchers have recently discovered a subspecies, nicknamed Goundry, which they believe lives outside the home. Malaria-carrying adult mosquitoes have originally thought to live inside the home, where most cases of malaria are contracted. This data is biased due to collection of adults in the home only. The idea of outdoor-dwelling malaria-carrying mosquitoes is not a new idea. It has been floating around since the 1970s; however, only recently has this new subspecies been in the spotlight.

Finding evidence that Goundry is both outdoor-dwelling and responsible for human cases of malaria is hard to do. Outdoor capture of adult mosquitoes is near impossible. Bait traps rarely work, and using humans as bait is understandably not allowed. Instead, researchers have been catching aquatic larval mosquitoes, raising them in a laboratory, and looking for genetic markers of the Goundry subspecies. While the scientists have been able to identify the new subspecies and its outdoor-living behavior, there is still no conclusive evidence that this mosquito is a threat to humans as humans may not even be its target; many malaria-carrying mosquitoes do not feast on humans.

So what does this mean if Goundry does bite humans? It could mean a perpetual step backwards in the fight against malaria. Indoor insecticide sprays have been used in the past in hopes of decreasing the rate of malaria, but this has no effect on the outdoor subspecies. However, this issue is small compared to the fact that the Goundry subspecies acquires the malaria parasite more easily than other malaria-carrying species. When fed blood infected with the parasite, 58% of Goundry mosquitoes picked up the parasite, compared to only 35% with other mosquitoes. While the efforts will still continue to find out more about this mosquito and methods of eradicating malaria, people in the infected areas of the world could be at more risk than they think.

Posted by Marlena Grasso (2)

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