Scientists to fight malaria via spermless mosquitoes

Female mosquitoes just don't get to have any fun. They mate only once, lay eggs, and eventually die.

In an effort to combat malaria, researchers at Imperial College London hope to take advantage of the female mosquito's plight--and reduce the mosquito population--by engineering spermless males. They say the key is that the females don't seem able to tell the difference; they still mate with the sterile males and proceed to lay eggs that never hatch.

This is an improvement over previous attempts to engineer sterile males, the team said, because that process often exposed the males to radiation, leaving them frail and unattractive to their female counterparts. In this latest achievement, the sterile males were just as attractive to females because the single difference from fertile males was an undetectable absence of sperm.

In work that was reported this week in the Proceedings of the National Academy of Sciences, entomologists injected 10,000 mosquito embryos with tiny fragments of RNA that turned off the gene "zpg," which is key in sperm development.

After several months of work they were able to create 100 spermless mosquitoes, and determined that females were just as willing to mate with their spermless creations as they were with fertile males.

Given that nearly a million people die from malaria every year--a disease that accounts for a whopping 20 percent of all childhood deaths in Africa--the end goal of releasing enough spermless males into the world to eventually reduce the population is a truly enormous task. But it now looks at least possible.

"You [could] in principle release large numbers of sterile males over many generations...and eventually all the females will have mated with the sterile males and...you can really reduce the number of mosquitoes," says entomologist Flaminia Catteruccia of Imperial College London.

But the team emphasized that its work is only proof of principle, and was so laborious that new methods would need to be developed to have any discernible effect on the global population of mosquitoes. And before any of these mosquitoes get released in the wild, scientists would have to carefully explore any potential unintended consequences to the ecosystem if a drastic reduction in mosquito population were to take place.

The key achievement of this research, ultimately, is that they were finally able to trick the females. Let the comments begin.