Could Modified Mosquitoes Eradicate Malaria?
Researchers have discovered a way to potentially eradicate malaria by introducing genetically modified mosquitoes into general mosquito populations. These insects almost exclusively produce male offspring, reducing the population numbers of the disease-carrying females in an extremely short amount of time.
According to a study published in Nature Communications, researchers from Imperial College London developed a genetic method that changes the potential for Anopheles gambiae mosquitoes - the main transmitters of malaria - to produce 95 percent male offspring.
Among these pesty bugs, only females feed on blood, while males essentially live their short lives only to reproduce. By significantly cutting the rate of female birth, researchers hope to cull female populations in a limited number of short-lived generations, reducing the number of females in a region that can carry and transmit the malaria parasite to humans.
Nikolai Windbicheler, co-leader of the study, told Reuters that once a few modified mosquitoes are introduced into a population, the eradication process is "self-sustaining."
In an experiment involving five caged and unmodified wild mosquito populations, the introduction of new modified males resulted in the eradication of four of the five cages in six generations (about 12 weeks).
Eradication occurs after the modified genes become more and more prevalent in the population, until none of the remaining mosquitoes can produce a female.
"Essentially the mosquitoes carry out the work for us," Windbicheler said.
According to the World Health Organization, malaria kills an estimated 627,000 people worldwide each year, most of them infants and small children.
This, the researchers argue, is reason enough to remove Anopheles gambiae. However, many experts can't help but wonder what eliminating an entire species could do to world ecosystems.
According to an article published in Nature back in 2010, eliminating mosquitoes may not have much of an impact at all.
Ecologists have discovered that because mosquitoes essentially exist only to reproduce (collecting blood exclusively for their eggs), they are actually a poor source of sustenance even for the insects' primary predators, and are certainly not a predator's first choice.
If an animal is expending energy just to hunt flying insects, they are far more likely to go for the "22-ounce filet-mignon moth" than the "6-ounce hamburger mosquito," entomologist Janet McAllister of the Centers for Disease Control and Prevention (CDC) explained in the article.
However, some rare species would be severely impacted.
"The mosquitofish (Gambusia affinis), for example, is a specialized predator - so effective at killing mosquitoes that it is stocked in rice fields and swimming pools as pest control - that could go extinct. And the loss of these or other fish could have major effects up and down the food chain," according to the report.
So there are some factors the world needs to consider before releasing this new end-all to mosquitoes into the world.
Still, the study does establish that as long as male populations cannot migrate to populate elsewhere, isolated eradication is possible - keeping the option open as the threat of malaria and other mosquito-borne illnesses bares down on the world this summer.