SMELLY armpits may turn you into a mosquito magnet, according to new research.
They hold the key to why some people are plagued by the critters – and others get off scot free, scientists say.
GettyMosquitoes are drawn to body odour, according to new research[/caption]
A study found the pesky insects are drawn to body odour – or BO – and can find us from 350ft away once getting a whiff.
They then leave an itchy bite – or worse if carrying deadly diseases.
The findings are based on the African malaria mosquito, Anopheles gambiae, which were let loose in an ice rink-sized outdoor testing arena in Zambia.
A team from Johns Hopkins University, Baltimore, released 200 hungry mosquitoes each night and used infrared motion cameras to observe how often they landed on evenly spaced pads heated to 35C – mimicking human skin.
This was a good sign they were ready to bite.
The initial results showed body odour was a more attractive bait than CO2 – a known cue for mosquitoes.
But further tests showed the swarm were also choosy.
The aromas of six volunteers sleeping in single-person tents were piped onto the pads over six consecutive nights.
It enabled the researchers to record the mosquitoes’ preferences and collect nightly air samples to compare airborne components of body odour.
Senior author Dr Conor McMeniman said: “These mosquitoes typically hunt humans in the hours before and after midnight.
“They follow scent trails and convective currents emanating from humans, and typically they will enter homes and bite between around 10pm and 2am.
“We wanted to assess mosquito olfactory preferences during the peak period of activity when they are out and about and active and also assess the odour from sleeping humans during that same time window.”
Night after night, some people were more attractive to mosquitoes than others.
One volunteer, who had a strikingly different odour, consistently attracted very few mosquitoes.
The study identified 40 chemicals that were emitted by all of the humans, though at different rates.
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Co-first author Dr Stephanie Rankin-Turner said: “It is probably a ratio-specific blend they are following.
“We don’t really know yet exactly what aspect of skin secretions, microbial metabolites, or breath emissions are really driving this, but we are hoping we will be able to figure that out in the coming years.”
People who were more attractive consistently emitted more carboxylic acids produced by skin microbes.
In contrast, the person who was least attractive gave off fewer – but triple the amount of eucalyptol, a plant compound.
It is found in oils, herbs and spices. Elevated levels may be related to diet.
The researchers were surprised by how effectively the mosquitoes could locate and choose between potential human meals within the huge arena.
First author Dr Diego Giraldo said: “This is the largest system to assess olfactory preference for any mosquito in the world.
“And it is a very busy sensory environment for the mosquitoes.”
Dr Rankin-Turner added: “When you see something moved from a tiny laboratory space where the odors are right there, and the mosquitoes are still finding them in this big open space out in a field in Zambia, it really drives home just how powerful these mosquitoes are as host seekers.”
The study, published in the journal Current Biology, could lead to the development of more effective repellents and traps.
Last week another US team found mosquitoes were put off by coconut scented soaps.
SWNSThe ice rink-sized testing area and surrounding tents used in the study[/caption]
SWNSThe aromas of six volunteers sleeping in single-person tents were piped onto pads[/caption] Read More