February 20, 2012
Insects cover our planet. Filed into 750,000 different species, at any given time there are one million trillion bugs buzzing around the globe.
About 14,000 of those species are blood-feeders, meaning they drink their meals by puncturing the skin of vertebrates, including humans. Besides being a nuisance, blood-feeding insects, such as certain strains of mosquitoes, are infected with parasitic organisms that are no threat to the bugs themselves, but if transferred to humans, become toxic, or worse, lethal.
A new collection of studies from PLoS charts alternative strategies for curbing mosquito-borne diseases such as dengue and malaria using genetically modified insects. The idea is to create mosquitoes that are less infectious and pass their altered genetics to the next generation by breeding with their natural counterparts.
Even though GM insects offer potential relief from malaria and dengue, which remain untreatable, unpreventable diseases in much of the developing world, there is still a lot of skepticism, mistrust and even fear of genetically modified organisms of any sort. Careful regulation, program oversight, and public information campaigns are just as important as proving the efficacy of GM insect release.
These pictures show the different types of mosquitoes whose genetic profiles are changing in the name of science and public health.
Above:
Aedes aegypti
Aedes aegypti is a carrier mosquito for the virus that causes dengue fever in humans. Researchers discovered that by introducing Wolbachia bacterial strains into some insects, the dengue virus didn’t live as long as usual inside the mosquitoes. What’s more, because most Wolbachia strains are relatively harmless to the insects, the bacteria spread through mosquito generations, passing from mother to offspring.
A study in Zhiyong Xi’s lab at Michigan State University found that the Wolbachia bacterium stopped the dengue virus from replicating, and therefore kept it from spreading among mosquitoes. In fact, 14 days after the study started, 37.5 percent of the mosquitoes were unable to infect humans with dengue.
Another study, from Elizabeth McGraw’s lab at The University of Queensland, Australia, showed that by using a modified Wolbachia bacteria (wMelPop), the older mosquitoes -- the insects that typically pass dengue to humans -- had a shortened lifespan because they could no longer feed. From the age of 26 days onward, the mosquitoes with the wMelPop Wolbachia bacteria in their bodies started drinking significantly less blood than their uninfected counterparts.
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SOURCE: Wired.com
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