Targeting the Mosquito’s Sense of Smell

Targeting the Mosquito’s Sense of Smell


Mosquitoes…it seems no matter where you
go, there they are, clamoring to feed on your blood. For many in the United States, the insects
are just a backyard nuisance. Worldwide, however, blood-feeding mosquitoes are responsible for
the spread of debilitating infectious diseases, such as malaria, dengue fever, and West Nile
encephalitis. Like many insects, mosquitoes devour the sugary
nectar of plants to produce energy. But to generate eggs, the female mosquito requires
an extra ingredient: the proteins found in blood. She will hunt high and low in search
of a suitable host, but how does she ultimately find us? Adriana Costero-Saint Denis is a program officer
at the National Institute of Allergy and Infectious Diseases, or NIAID. She oversees research
aimed at understanding the biology of mosquitoes and other vectors of human diseases. “The reason that mosquitoes need to feed on
our blood is to reproduce, so the way that they find us is through olfaction.” Mosquitoes use olfaction, or their sense of
smell, to locate a potential blood meal. When we exhale, we emit a ball of carbon dioxide
that forms into a plume. Female mosquitoes encounter this plume and follow it back to
the source. As they get closer, they sense the odors emitting from our skin, confirming
that we are a source of food. “When mosquitoes find us and bite us, or blood
feed from us, that’s when they transmit infectious disease agents, so if we can prevent mosquitoes from finding us, then we can prevent transmission of diseases.” NIAID funds several research projects aimed
at understanding the biology of the mosquito’s sense of smell. For example, Anand Ray at the University of
California, Riverside, is an NIAID grantee looking at ways to inhibit the function of
the insect’s odor receptor genes. “In my lab, we’ve been able to find odors
that can block these sensors in the antennae of the insect and therefore block the ability
of the mosquitoes to find us.” Dr. Ray and his colleagues identify compounds
that can activate or disrupt the insect’s carbon dioxide detectors. They then evaluate these compounds as repellents
to prevent mosquitoes from biting people or as attractants for the development of traps. “What we are trying to do is develop simple
and affordable odor molecules that can block attractive behavior of mosquitoes towards
human beings and create affordable programs that are environmentally safe, that are suitable
for places like Africa and Asia, where disease transmission is most prevalent.” Today, the best way to avoid mosquito bites
is to cover exposed skin by wearing long-sleeved shirts, long pants, and hats; stay indoors
at dawn and dusk, when the insects are most active; and follow all instructions when using
mosquito control products, such as repellents that contain DEET. For more information about NIAID-supported
research, visit our website. For more information on how to prevent mosquito
bites, visit the website of the Centers for Disease Control and Prevention. For information on the proper use of insect
repellents, visit the website of the Environmental Protection Agency.

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