Confusing Mosquitoes to Fight Deadly Disease

This image, put together by a UC Riverside researcher, shows the head and olfactory organs of a female mosquito (in foreground) and a fruitfly (background). The red lines are sample electrical recordings from a CO2-sensitive neuron. The red and black molecules show the chemical structures of compounds the research team tested. (Stephanie Turner)

As summer begins, thoughts often turn to hot dogs, hamburgers, watermelon … and mosquitoes.

For most barbecuers, the bugs are little more than a pesky annoyance.  But for millions around the world every year, mosquitoes carrying diseases such as malaria, dengue fever and West Nile virus prove deadly.  Mosquito nets and repellants help fight bites, but public health officials still seek cheaper and more effective ways to fight mosquito-borne disease.

Enter researchers at UC Riverside, who reported Wednesday in the journal Nature on three classes of odor molecules that could potentially keep mosquitoes away from people.  The chemicals work by blocking the mosquitoes’ ability to detect carbon dioxide — the key cue that leads the insects to their human victims.  Mosquitoes zero in on exhaled breath to find you and make you their lunch.

The types of odor molecules work in three ways.  The first set inhibits mosquitoes’ and flies’ carbon-dioxide receptors.  The second set mimics carbon dioxide.  The third set overstimulates carbon-dioxide-sensing neurons, making them unable to detect CO2 for several minutes.

Though the compounds haven’t yet been approved for use in humans, UC Riverside researchers think they might be used to create traps that could replace the bulky and expensive CO2-spewing models in use today.

“Odor molecules that mimic carbon dioxide activity … can lead to the development of small and inexpensive lures to trap mosquitoes — a great benefit, especially to developing countries,”  said Anandasankar Ray, an assistant professor of entomology at UC Riverside, in a press release.

The research, which included wind-tunnel experiments and other tests, tested the compounds on three disease-carrying mosquitoes: Anopheles gambiae (which transits malaria), Aedes aegypti (dengue and yellow fever) and Culex quinquefasciatus (West Nile virus and filariasis, also known as elephantiasis). The work was funded by the Bill and Melinda Gates foundation.

UC Riverside has patents on the discovery, which it has licensed to a new startup, Olfactor Labs.  The company plans to have product prototypes in 2012.

For more information about products currently available to ward off mosquito bites, check out this piece on natural repellents and this story on DEET drawbacks.  Read here for tips on choosing an insect repellant.

Los Angeles Times reporter Amina Khan wrote in April about efforts to engineer genes to fight malaria and in February about a mosquito subspecies that was making work harder for health workers.

By Eryn Brown, Los Angeles Times / for the Booster Shots blog

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