Chemical Compounds From Human Odors Stimulate Mosquito-Borne Diseases Like Dengue Fever [STUDY]

Mosquitoes spreading yellow fever, Zika, and dengue are guided toward the people they are landing on by a scent from human skin.

That scent's exact composition, a Phys.org report said, has not been determined until now. The team led by UC Riverside found that the combination of carbon dioxide plus two chemicals, including lactic acids and 2-ketoglutaric, elicits an odor that causes a mosquito to find and land on its victim.

The chemical cocktail also encourages probing, using piercing mouthparts to look for blood. Furthermore, the chemical mixture appears to particularly attract female Aedes aegypti mosquitoes, Zika vectors, as well as chikungunya, yellow fever viruses, and dengue.

This mosquito originated in Africa, although it has spread to tropical and subtropical regions globally, including the United States.

Mosquitoes Using Assortment of Hints to Find Victims

The new study finding and how the researchers discovered them are detailed in the Scientific Reports journal. According to UCR entomologist Ring Carde, even though others have identified compounds attracting mosquitoes, many of them do not elicit a robust, rapid effect. "This one does," he specified.

Mosquitoes use an assortment of hints to find their victims, which include sight, humidity, temperature, and carbon dioxide.

However, this recent research by Carde demonstrates that skin odors are even more essential for pinpointing a biting area.

He also explained they demonstrated that mosquitoes land on visually obscure targets infused with the two odors, and these targets are not associated with either moisture or heat. This leaves the skin odor as "the key guiding factor." the expert elaborated.

Discovering Chemicals to Make Human Scents Potent for Insects

Given the substantiality of odor in helping mosquitoes feed on humans successfully, Carde wanted to find the exact chemicals to make human scent so potent for the insects.

Lactic acid, part of the equation, was identified as one chemical element in the odor cocktail as long ago as 1968.

Since then, several studies have determined that carbon dioxide incorporated with ammonia, as well as other chemicals produced by humans, attracts mosquitoes, as well.

Carbon Dioxide Combined with Ammonia as a Mosquito Attractor

Since then, several studies have identified that carbon dioxide combined with ammonia, and other chemicals produced by humans also attract these mosquitoes.

Nevertheless, Carde has investigated mosquitoes for over a decade and felt these other chemicals were not robust attractants.

He explained something unexplored about the odors' chemistry, luring the yellow fever mosquito. Carde added he wanted to nail down the exact blend.

Techniques that chemicals usually use to determine these chemicals would not have worked for 2-ketoglutaric acid, explained Carde.

Potential for Killing Disease-Spreading Mosquitoes

Looking for mosquito attractors, Carde turned to Jan Bello, a chemist formerly from the UCR and now affiliated with Provivi, an insect pest control firm, who extracted compounds from the sweat on his feet.

Bello filled his socks with glass beads, then walked around with the beads in his socks for four hours each odor collection, a similar Bioengineeer.org report specified.

The chemist added wearing the beads felt nearly like a massage, like squeezing stress balls filled with sand, although with the feet.

This discovery may not lead to an understanding of the formulation of new repellants, but the researchers are hopeful that such a discovery can be employed to attract, trap, and possibly kill disease-spreading mosquitoes.

Related information about how mosquitoes spread viruses is shown in Vincent Racaniello's YouTube video below:

Check out more news and information on Mosquitoes in Science Times.