• Researchers conducted a study to find out how different human body odors can attract mosquitoes.
  • A facility was set up where hundreds of mosquitoes were exposed to scents from humans.
  • Their study suggested mosquitoes were attracted to carboxylic acids, including one found in dairy.

Researchers learned the key ingredient in human body odor that may be particularly attractive to mosquitoes — and the answer can be found in cheeses.

In a study published on Friday with Current Biology, researchers from Johns Hopkins Malaria Research Institute and the School of Medicine partnered with the Macha Research Trust in Zambia to find out what traits in various human body odors are more appealing to mosquitoes.

The research used a 20-meter by 20-meter screened cage that contained hundreds of African malaria mosquitoes, according to the study. Despite the name, the mosquitoes were not infected with malaria, according to CNN, which first reported on the study.

Around the facility are eight one-person tents. These tents are connected to the cage in a way that the human body odor can be safely fed to the mosquitoes.

Researchers found that mosquitoes gravitated to human body odor with "increased relative abundances of the volatile carboxylic acids," including butyric acid. Butyric acid is a fatty acid humans produce in their gut, but it's also naturally occurring in butter, "hard cheeses" such as parmesan, milk, yogurts, and cream, according to a separate study published in the National Library of Medicine. The acid can also be found in some fermented foods such as sauerkraut and pickled cucumbers, according to the study.

In contrast, mosquitoes were less attracted to body odor deprived of carboxylic acids and "enriched with the monoterpenoid eucalyptol," the Johns Hopkins and Mach researchers found. Eucalyptol can be found in tea tree oil and cannabis sativa, according to the American Chemical Society.

According to PubChem, the compound is also commonly present in mouthwash and cough suppressants.

Conor J. McMeniman, a professor at the Johns Hopkins Bloomberg Public School of Health and one of the co-authors of the study, did not immediately respond to a request for comment sent outside of working hours.

"This finding opens up approaches for developing lures or repellents that can be used in traps to disrupt the host-seeking behavior of mosquitoes, thereby controlling malaria vectors in regions where the disease is endemic," Edgar Simulundu, one of the co-authors of the paper, told CNN.