Putting Mosquitoes On A Diet Might Help Stop Them From Biting Humans

New research finds that feeding mosquitoes human diet drugs causes them to lose their taste for human blood for days. The researchers hope this could be used to reduce the spread of disease.

MARY LOUISE KELLY, HOST:

Scientists have come up with a novel way to try to stop mosquitoes from biting humans. They put them on a kind of diet - seriously. NPR's Merrit Kennedy tells us how.

MERRIT KENNEDY, BYLINE: Wouldn't it be great if mosquitoes weren't hungry for blood? Scientists already knew there is a time the insects aren't interested in feeding, and one research team thought that if they could figure out why, they could potentially change the mosquitoes' behavior. The mosquito species Aedes aegypti, which spreads the Zika virus, can double its body weight from a blood meal. And after that, it won't try to feed again for days.

LESLIE VOSSHALL: So even if you put your arm in a cage of female mosquitoes, they won't even get up and look at you. They really have no interest.

KENNEDY: Female mosquitoes are the ones that suck blood. Leslie Vosshall and her team at The Rockefeller University in New York wanted to trick them into thinking they'd just had a meal. The team thought that disinterested feeling in mosquitoes might be triggered by the same hormonal pathways that humans have. And plenty of drug companies have been working on diet drugs to switch off those pathways and make people feel full.

VOSSHALL: So we just started calling different drug companies to see if they had drugs that were in the pipeline in human drug development that they could give us that we could test in mosquitoes. They all thought this was a really weird request, but several of them were on board and sent us drugs.

KENNEDY: The team tested 24 different diet drugs, mixing them into a saline solution with a special ingredient that made it taste more like blood to mosquitoes. On the 18th kind, they hit the jackpot.

VOSSHALL: And immediately saw that it worked, which was amazing.

KENNEDY: For several days, mosquitoes that took the drug showed no interest in feeding.

VOSSHALL: Everything about them - they are convinced that they've had the most delicious blood meal ever.

KENNEDY: Vosshall hopes a version of the drug could be produced cheaply and potently so that it could one day be used in traps outdoors. It has the potential to help reduce the spread of dangerous mosquito-borne diseases such as yellow fever and dengue. Zainulabeuddin Syed, an entomologist at the University Kentucky, calls it a tour de force of ingenuity.

ZAINULABEUDDIN SYED: It's really interesting work, very well done. People have been thinking about this for decades now.

KENNEDY: Vosshall's team is now trying to figure out if the diet drugs work as well on other kinds of mosquitoes like the kind that carry malaria. Merrit Kennedy, NPR News.

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