Noah Fromson

Cornell professor Laura Harrington presents her findings to a panel at the National Press Club which explored the reproductive systems of mosquitoes carrying the Zika virus.



WASHINGTON — Zika researchers need to shift focus from male to female mosquitoes because mating could be the key to controlling the virus, an expert said Tuesday.

Scientists have been working on genetically modifying the aedes aegypti mosquito, which carries the Zika virus. The modified males pass on a lethal gene to females that make their offspring die. FDA analysis of these modified males found little risk in releasing them into the wild.

There is widespread public support for these projects. A national survey conducted last month by Purdue University said 78 percent of responders supported introduction of genetically modified mosquitoes into the U.S. to slow the Zika outbreak.

So, there is a focus on modifying males, but tweaking the genes of male mosquitoes affects their fitness, said Laura Harrington, a Cornell University professor and mosquito expert who worked on the study.

“It’s really difficult to produce males that are as fit as wild type males, and females have a choice in who they mate with,” Harrington said. “And so they can mate with a modified male or a nice, fit, wildtype male. So that’s a challenge here.”

A new study at Cornell University found that mating is directly linked to a female mosquito’s capacity to spread viruses because of genetic changes to her reproductive system after consummation. These changes “prime” her for processes like blood feeding and egg development, the study said.

“Reproduction is the Achilles’ heel of the mosquito lifestyle,” Harrington said. “If we can get in there and prevent females from reproducing or prevent females from being fertile, we can limit the populations and limit the spread.”

Harrington and her research team are looking to uncover a molecule that is critical to the fertility of female mosquitoes. If the search is successful, scientists could create a chemical inhibitor that wouldn’t stop a female from producing eggs, but she wouldn’t be able to lay them, she said.

Harrington’s research also covers other non-traditional methods of reducing mosquito populations like using sound, which is attractive to mosquitoes, to trap them.

“Genetic modification is just one strategy,” Harrington said. “We’re not just going to have a silver bullet — you’re going to have to have a lot of different strategies.”