Always bugged by mosquitos? Blame your body odour

When it comes to mosquitos, having unattractive body odour may actually be a good thing – but what is attractive to a mosquito? A team of scientists developed an ice-rink-sized outdoor arena in Zambia to find out how mosquitos hunt us over longer distances, and discovered that body odour plays a key role in making some humans more attractive to them than others.

These findings “could potentially contribute to the development of more effective mosquito control strategies, leading to better prevention of mosquito-borne diseases”, Alicia Showering, a doctoral candidate at the London School of Hygiene & Tropical Medicine who was not involved in the research, told BBC Science Focus.

This study, published in the journal Current Biology, is one of the first to test how the Anopheles gambia mosquitos (the most efficient malaria vectors in Africa) locate human hosts over longer distances in a ‘real world’ setting – the 1000m³ arena in Choma District, Zambia – rather than in a lab.

Researchers from the John Hopkins Bloomberg School of Public Health’s Malaria Research Institute and Macha ResearchTrust compared heat, body odour, and the release of CO₂ in human breath as lures in the mosquito hunting process.

The arena contained landing pads heated to human skin temperature (35°C). On each of the six nights in the study, they released 200 hungry mosquitos into the arena and monitored them with infrared cameras. When they landed on the pads, it signalled that they were ready to bite.

Six people were sleeping in single-person tents around the arena for the duration of the week, with pipes leading from their tents into the arena. But these pipes were not nightmarish, streamlined hunting funnels for the mosquitos (thankfully). Instead, the researchers used repurposed air conditioning ducting to pump air from each tent – and the body odours it contained from the sleeping participants – onto the landing pads.

The researchers found that one lucky volunteer had a completely different body odour composition to the others and consistently avoided the mosquito’s attention.

“We don’t really know yet exactly what aspect of skin secretions, microbial metabolites, or breath emissions are really driving this, but we’re hoping we’ll be able to figure that out in the coming years,” said Stephanie Rankin-Turner, a postdoctoral fellow at Johns Hopkins Bloomberg School of Public Health and one of the study’s authors.

The team identified different blends of the same 40 chemicals in the odour of all six humans. Each person’s blend may be impacted by diet, skin secretions, microbes, and breath emissions, among other factors.

For mosquitos, some humans are more attractive to others – but by identifying these people, “we can isolate and study the volatile compounds in their body odour,” says Showering. “These odours could be synthesised to develop better, more attractive baits for mosquito traps, thereby reducing mosquito bites and the subsequent transmission of deadly diseases like malaria.

“This research has the potential to lead to new tools in the fight against malaria in the future, which could improve the quality of life and health outcomes in areas where the disease is most prevalent.”