Research reveals targeting mosquito sperm storage could help combat malaria

A collaborative team of researchers published study results on April 7 that showed reducing the fertility of malaria-carrying mosquitoes may provide a new avenue to control the disease.

The research was published in Proceedings of the National Academy of Sciences, and showed that affecting the sperm of Anopheles gambiae mosquitoes caused the female of the species to fertilize fewer eggs.

Female Anopheles gambiae mosquitoes mate only once during their lifetime, storing the sperm in a spermatheca. The female retrieves sperm from the spermatheca to fertilize the eggs it lays. The sperm are protected by an enzyme called HPX15, and when the enzyme was altered, fewer eggs were fertilized.

"Malaria kills over 650,000 people every year and we need to find new ways of tackling it, partly because mosquitoes continue to evolve ways of resisting our efforts," Imperial College London Department of Life Sciences Researcher Robert Shaw said. "We are interested in cutting the numbers of malarial mosquitoes by impairing their ability to reproduce, and our new study suggests a way that we might be able to do this. There is no single magic bullet for tackling malaria, but making mosquitoes less fertile could provide us with a valuable weapon against the disease."

Researchers were able to discover how HPX15 is activated, which offered another route to impacting fertility and rate of reproduction.

"We've managed to disable HPX15 in mosquitoes in the lab, but we don't yet have a way of replicating this in wild mosquitoes," Harvard School of Public Health Associate Professor Flaminia Catteruccia said. "The next step for this research is to think about how we could prevent activation of either the enzyme that protects the sperm, HPX15, or of the male trigger 20E that kicks that enzyme into action. There may also be other pathways that we could target, and this is something that we're keen to investigate."