Has science finally figured out why mosquitoes prefer some people to others?
A new study from Rockefeller University in New York found that some people attract mosquitoes by how they smell to those mosquitoes.
Speaking to The New Daily, Associate Professor Cameron Webb, a mosquito expert at NSW Pathology who wasn’t involved in the study, said the findings were important – because the reason why some people are mosquito magnets and not others is a “great mystery”.
“We know that some people just simply don’t attract too many mosquitoes, and some people attract a lot,” Dr Webb said.
“So it’s really good to kind of work out exactly what’s going on, and how they’re kind of making a decision on who to bite.”
What smells good to mosquitoes?
The research focused on the Aedes aegypti, the type of mosquito that spreads diseases like yellow fever, Zika and dengue.
People who produce higher levels of carboxylic acids attract more mosquitoes, the study found.
The level of attraction appears to work on a sliding scale, depending on the amount of carboxylic acid mixed in with a person’s body odour.
We all produce these acids in sebum, the oily layer that coats our skin. They’re part of the skin’s natural moisturiser – and they’re also used in the production of soap.
Professor Webb said the smell produced by these acids likely doesn’t smell too good to the human nose.
Australia has about 300 different types of mosquitoes – the Aedes aegypti mosquito is only found in central and Far North Queensland.
“So most Australians are not getting bitten by this mosquito,” Dr Webb said.
“They’re getting bitten by dozens of other local mosquitoes, which all may actually have different tastes for biting individuals.”
Mosquitoes love water
Dr Webb said there are two ingredients that mosquitoes need to maintain their lifecycle – warmth and water.
With parts of Australia’s east coast being hit with downpours and floods, we can expect to see a big increase of mosquitoes.
But not just yet.
“Even though we’ve got water everywhere at the moment, the temperatures in many parts of the country are relatively mild, and so that probably keeps some of the really dramatic increases of mosquitoes in check,” he said.
“The thing is, over the weeks and months ahead, all of the flood waters are going to start to recede, you’re going to get stagnant pools, ponds and puddles all over the place.”
When the water finally recedes in the coming weeks, that’s when the temperature will start to increase. Once that happens, it will be a more suitable time for mosquitoes to breed.
With the emergence of the Japanese encephalitis virus there is a heightened concern as Australia heads into the warmer months.
What keeps mozzies away?
The old wives tale about gin and tonic deterring mosquitoes comes from the fact people used to drink tonic water to ward off malaria.
However, most tonic water these days doesn’t use quinine, the ingredient that helps relieve malaria symptoms.
All you achieve by enjoying a gin and tonic is getting your mind off mosquitoes, Dr Webb says.
Vitamin B is also supposed to repel mozzies, however, the evidence to back the claim is only anecdotal.
Actual studies conclude, for the most part, Vitamin B does nothing to prevent being bitten, Dr Webb said.
Instead, he recommends applying a repellent, liberally.
A repellent bought at the supermarket is fine, but a few spritzes won’t cut it. You need to apply it as you would a sunscreen, to all areas of skin that are exposed.
Clothing can also help. Loose clothing that covers everything is ideal – tight clothing or activewear will allow mosquitoes to bite through the fabric.
Reducing stagnant water around the home will also decrease your chances of mosquito bites.
Huge challenge ahead
Although a hindrance, mosquitoes are part of Australia’s ecosystem “as much as kangaroos, koalas, birds and frogs”, Dr Webb said.
In some circumstances, we need to learn to live with mosquitoes. However, they are moving into major cities around the country.
Dr Webb says there is potentially a huge challenge ahead as mosquito populations explode after severe weather events linked to climate change.
