Representational Image

(BCCL)

Has mosquito music taken over your dreams? Do your mornings begin with eyebags and irritating itchy red bumps? Have these pesky little fliers trumped all your tried and tested remedies while the rest of the world goes about its business unbothered? If you have answered yes to all these questions, then you, my friend, are perhaps a mosquito magnet!

There exist a lot of theories as to why mosquitoes target some people more than others — these factors range from blood type, blood sugar level and consumption of garlic or bananas, to being a woman or even a child.

What makes mosquito magnets, mosquito magnets?

A group of researchers from Rockefeller University set out to find a definitive answer. Over a span of three years, they studied the response of Aedes aegypti female mosquitoes — the primary vector species for diseases like zika, dengue, yellow fever and chikungunya — towards a set of nylon stockings worn by the eight participants of this experiment.

The female mosquitoes were placed in a plexiglass chamber and could fly via tubes to either of these eight stockings. Whichever stockings the mosquitoes were most compelled to were labelled the most attractive subjects.

The mosquitoes clearly had a preference, as they found one particular participant’s stockings four times more attractive than the next-most compelling participant, and an astonishing 100 times more appealing than the least attractive. After sorting through the stockings marked by the intensity of attraction, the researchers then ran assays to determine why.

Chemical analyses were used to identify 50 molecular compounds that were elevated in the high-attracting participants’ sebum (a moisturising barrier on the human skin). This helped researchers identify the main culprit: a compound called carboxylic acid, which the mosquito magnets produced but the others didn’t. The bacteria on human skin use such organic compounds in the sebum to create a distinct human odour.

“There’s a very, very strong association between having large quantities of these fatty acids on your skin and being a mosquito magnet,” says Vosshall, the Robin Chemers Neustein Professor at The Rockefeller University and Chief Scientific Officer of the Howard Hughes Medical Institute.

Even after 50 more participants were enrolled for a subsequent validation study, the mosquitoes’ preference did not budge. They remained loyal to their favourite meal, not just for a few days but for years!

The scientists even knocked out the olfactory receptors of female mosquitoes in hopes of engineering ones that could not spot humans, but all in vain. Turns out these insects love their food so much, that they have evolved failsafe techniques to hunt the humans down!

Will the mosquito magnets remain ‘magnetic’ forever?

So far, two things have been established: First, mosquitoes’ scent trackers are unbreakable (obviously due to years of evolution!); and second — once a mosquito magnet, always a mosquito magnet… at least for now.

While such magnets are not getting off the mosquito menu anytime soon, researchers are hopeful that meddling with skin microbiota or having a dietary or microbiome intervention that changes how these bacteria interact can probably turn mosquito magnets into mosquito repellents.

Elaborating on this possibility, Leslie Vosshall, head of Rockefeller’s Laboratory of Neurogenetics and Behavior, added: “That’s a hard experiment. But if that were to work, then you could imagine that by having a dietary or microbiome intervention where you put bacteria on the skin that are able to somehow change how they interact with the sebum… But that’s all very speculative.”

In the meantime, while reports of dengue and chikungunya outbreaks emerge from many parts of India, it is crucial to do everything possible to keep away from these disease-carriers.

Some important measures include keeping our surroundings clean, not letting water collect in our homes or surroundings, covering up our bodies well and, if possible, using mosquito nets and repellents. And keeping our weapons of choice (a newspaper or an electric racquet) by our bedside is always a plus.

The study was published in the journal Cell earlier this week and can be accessed here.

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