In every group of student travellers, there’s always at least one who mosquitoes find irresistible. But why do these biting pests find some of us more attractive than others?
Wherever your travels take you, chances are, you’ll find mosquitoes in residence. With over 3,700 mosquito species living all over the world, except in Antarctica, it’s hard to get away from them. Although you may see large congregations of the insects at dusk and dawn, they’re active around the clock and always on the lookout for their next meal.
When a mosquito bites you, she (it’s always a female – the males don’t have the right mouthparts) pierces your skin with a sharp proboscis. As she drinks in blood, she excretes saliva into your bloodstream, which is why mosquitoes are so effective at spreading diseases, such as malaria and dengue. It’s also what makes a bite irritating. When the human immune system senses the saliva, it sends out histamine to fight the foreign protein, causing blood vessels and the skin to swell. That’s when the itching starts.
Mosquito magnets
Studies have shown that mosquitoes are attracted to some people more than others. And some people have more extreme reactions to bites than others. Where the two meet, it can be severely irritating. Although it’s an area where there’s still room for research, there are lots of theories to explain the mosquito-magnet phenomenon…
- Blood type: it’s suggested that people with type O blood are more appealing to mosquitoes. But not all researchers agree on this and as O+ is the most common blood type, this doesn’t really narrow the field.
- Odour: everyone has their own unique smell, which is imperceptible to the human nose, but can be sniffed out by mosquitoes from as far as 60 metres away. This odour is made up of chemicals such as carboxylic acid, lactic acid and ammonia, as well as microscopic bacteria that live on the skin. Some people don’t smell appealing to mosquitoes, while others are irresistible. As your individual smell is all down to your genetic make-up, there’s not much you can do to change it.
- Carbon dioxide: this is something else that mosquitoes are looking for in a victim – the more you give off, the more of a target you become. The insects detect CO₂ from your breath with their antenna and seek it out, which explains why they buzz around your head. If you’re exercising and breathing heavily, you’ll get more mosquito attention. As high body temperature also attracts mosquitoes, this is one area in which exercise is bad for you.
- Colours: mosquitoes appear to have pretty good eyesight but are picky about colours. They’re more likely to investigate black, navy or dark green clothing than white or pale shades.
Staying out of harm’s way
Whether you’re prone to a lot of bites or just a few, avoiding them altogether is the best course of action. There are a few sensible precautions to take, whether you’re travelling abroad or out and about in the UK.
Wear long sleeves and trousers to minimise the amount of skin mosquitoes can access and prevent swollen bites around the ankles and wrists, which can be especially uncomfortable. Garments treated with plant-based or synthetic insect repellents are available.
Choose pale-coloured clothing that’s less likely to catch the attention of mosquitoes.
Use mosquito nets, both when you’re sleeping and over your hat when you’re in an area where the insect population is high.
Take an antihistamine every day, even before you’ve been bitten, to prevent an over-enthusiastic immune response. Your doctor or pharmacist can advise if this is suitable for you and help you choose the right type of antihistamine.
Use an insect repellent and make sure you refresh it according to the manufacturer’s guidance. There are several chemicals approved for use on your skin. If you’d prefer to use an essential oil, lemon-eucalyptus, lavender, clove and tea-tree oils are all considered effective. Some people swear by garlic oil, but that may have the effect of repelling your friends, as well as insects.
Once bitten…
Even with your best efforts to foil them, mosquitoes are determined. If you do get bitten, the NHS advises washing the area with soap and water before applying an ice pack to reduce swelling. Paracetamol can help with pain, while ibuprofen also reduces inflammation. Scratching might be irresistible, but it can lead to infection, so minimising the itching with antihistamine cream or tablets can help reduce the temptation.
After being bitten, you might see a near-immediate immune response or a more delayed reaction. Some bites can be itchy and irritating for a week. If bites become infected, it can lead to cellulitis, which needs antibiotic treatment. Skeeter syndrome results in a more extreme reaction than normal to a bite. People with weakened immune systems can fall victim, as can anyone visiting an area where there are different mosquito species. Recognising what level of response is normal for you is important, especially when you’re travelling. If you see a reaction that’s more dramatic than usual, that’s the time to seek medical advice.