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  • Do mosquitoes bite some people more than others? Maybe you're the type of person who's constantly

  • itching when you're outside at night. Or you're the type that get hassled at all.

  • According to the experts, mosquitoes are picky about who they bite. But do we know why?

  • There's more than 300 species of mosquito in Australia, but only 20 pose a risk to human

  • health through disease or nuisance biting. You may also be surprised to learn it's only

  • female mosquitoes that bite and that's because they need an energy hit to develop their eggs.

  • But how does she do this? When she has found an animal or a person to

  • bite, she'll land on the skin and she'll start probing away at the skin with her proboscis

  • and the proboscis isn't a sharp, needle-like device, it's actually a little bit flexible.

  • So she can inject that into the skin, move around and find a source of that blood.

  • But also, the feeding tubes in the proboscis, some of them spit and some of them suck.

  • So the mosquito will inject some saliva into the skin - it has anti-coagulants, a little

  • bit of anaesthetic, it helps the blood feeding go through much easier, and then in other

  • tubes, the mosquito will suck up the blood.

  • So how does a female mosquito choose her next meal?

  • Researchers say she's initially attracted by the carbon dioxide we breathe out.

  • Then, when the mosquito gets closer, they respond to the heat of our body - the higher

  • your body temperature, the more likely you are to get bitten.

  • Scientists think the key attractor is the chemical of our skin produced by bacteria

  • and sweat, which signals how attractive, or not, we might be.

  • But, it's very difficult to tell exactly what bacteria or smells are appealing, and every

  • species of mosquito is slightly different in what it finds attractive.

  • There's also other factors that come into play, like the colour of our clothing.

  • Dark colours tend to attract mosquitoes more than light colours - perhaps they can see us moving

  • around more in dark clothing. Scientists also recently discovered a gene

  • in mosquitoes that leads them to bite some people over others, but they're yet to determine why.

  • And there's a load of other theories out there,

  • like eating garlic, or taking vitamin B will change how attractive we are to mosquitoes.

  • But science has failed, so far, to show any evidence this works.

  • We do know that some research shows that maybe diet has a subtle change to our attractiveness.

  • We know from studies in Africa that drinking beer may make us more attractive to mosquitoes

  • that spread malaria parasites. But it doesn't mean that avoiding drinking alcohol will prevent

  • you from being bitten by any mosquitoes.

  • Your blood type may also have an impact, though

  • scientists think not as much as the smell of your skin. Studies in Africa investigating

  • malaria transmission are examining whether type O blood attracts a few more mosquitoes

  • than other types. But just because you don't itch, doesn't mean

  • you weren't bitten at all. Everyone differs when it comes to their reaction to mosquitoes'

  • saliva, just like we do with certain foods. But putting up with nuisance biting isn't

  • the only worry when it comes to mosquitoes.

  • They can also carry disease, with the World

  • Health Organisation estimating there are more than 700,000 deaths every year from vector-borne

  • disease. Mosquitoes are carriers, along with others including ticks, sand flies and fleas.

  • It's for this reason that mosquitoes are considered the deadliest animals on the planet.

  • Malaria is perhaps the best-known of these diseases and causes more than 400,000 deaths

  • every year. Australia was declared free of malaria in 1981.

  • The disease we're most worried about in Australia is caused by Ross River Virus. We get thousands

  • of cases of human disease across Australia every year. It doesn't matter whether you're

  • in Cairns, or Hobart or Sydney, or Perth, there's a chance that in some of those areas

  • during some seasons you may be exposed to that virus. It's much more prevalent outside

  • metropolitan areas and the reason for that is that the mosquitoes don't hatch out of

  • the wetland infected with the virus. They have to bite an animal first, and typically

  • that's a kangaroo or a wallaby. So it's in these rural, or semi-rural areas where the

  • risk is much greater of mosquito-borne disease in Australia.

  • Ross River Virus has no treatment or cure so the best way to prevent the illness is

  • to stop mosquito bites. And there's plenty of ways you can do this.

  • Wearing long sleeves and long pants to minimise access to skin is one of them.

  • Using repellents, like sprays or lotions is another. Products containing DEET or picaridin or extract

  • of lemon eucalyptus are most effective. The higher the concentration, the longer it will

  • last on your skin and the less you will need to re-apply.

  • Burn mosquito coils and candles containing insecticides in outdoor areas. They'll help

  • protect you if you're within a few metres. Sitting under fans can also be useful as mosquitoes

  • can't fly easily in windy conditions. Other measures, like sound-emitting devices

  • and wristbands exist, but there's no evidence yet showing they work.

  • Wearing a colourful band on your wrist, no matter how strongly it smells, it won't provide

  • protection for the rest of your body.

  • Cleaning up around the home is another important

  • way of lowering mosquito numbers. They love breeding in pet water bowls or bird baths

  • so change the water regularly, and check for common places water collects like pot plant

  • drip trays, blocked gutters, toys, or old tyres.

Do mosquitoes bite some people more than others? Maybe you're the type of person who's constantly

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蚊に刺されやすい人がいる理由|知ってますか? (Why mosquitoes bite some people more than others | Did You Know?)

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    00348 に公開 2021 年 01 月 14 日
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