Some people seem to be mosquito magnets — the bugs come to them wherever they are and leave bites in any exposed flesh — while others remain relatively unharmed and free from itchiness.
How do mosquitoes choose their prey and how can we repel them? We spoke to some experts for their advice.
Leslie Vosshall, vice president and scientific director of the Howard Hughes Medical Institute, explained that a mosquito’s saliva has a quality similar to that of an anesthetic, so you don’t feel the bite until after the insect has flown away. It also has anticoagulants so your blood continues to flow without clotting.
“Mosquito saliva contains a lot of proteins, some of which are allergens,” said Vosshall, adding, “Our bodies recognize the mosquito protein as foreign, and our immune cells spring into action to try to fight it.”
It’s not the bite that causes the itch — it’s actually the body’s response to the foreign mosquito protein it’s trying to fight off. That’s why some people have only a mild reaction to bites, while others, who are more sensitive to the foreign protein, react with large swellings that are more painful.
And you don’t have to get mad at male mosquitoes, because only female mosquitoes sting. They bite to get a blood meal, as most female mosquitoes cannot produce eggs without that blood.
How do mosquitoes choose their prey?
“Once they actually get close to a host, they use a variety of other signals to eventually hone in,” he said. “These include visual components such as shapes, sizes and colors. Therefore, dark colors are not recommended in prime skeeter habitats as they stand out more, especially with regard to backgrounds and contrasts.”
Other chemical signals “including breath odors, microbiota byproducts on our skin or other common human odors such as octenol, ammonia, caproic acid or lactic acid” all combine with our carbon dioxide to make us more or less attractive to different types of mosquitoes, he added.
“This is something we’re working on — the amount and type of body odor a person gives off is probably the reason,” Vosshall said via email. “There are papers that claim it’s blood type, or sweetness in the blood, or sex (women are supposedly more attractive to mosquitoes), but nothing has been conclusively proven.”
What counters the urge to scratch?
“Don’t scratch” is the advice most experts and health professionals give. As harsh and sometimes unrealistic as it sounds, scratching makes the skin inflamed and the inflammation makes the skin more itchy.
“Scratching can also cause secondary infections and prolong irritation,” Markowski warned, adding that in extreme cases, people can scar themselves.
Instead, there are dozens of creams and sprays that promise itch relief, as well as home remedies and mosquito repellents, so choosing what’s right for you can often come down to trial and error.
“In general, all the different anti-itch creams are very similar,” Markowski said. “In general, I suggest that if you are highly allergic to mosquitoes, you may need a cream containing Benadryl or a similar antihistamine.”
Vosshall recommended applying hot water to the bite as soon as possible.
“If you’re out walking and that’s not practical, a lidocaine topical anesthetic gel can be helpful to prevent the itchy feeling, as can an over-the-counter cortisone cream.”
While both experts said many people prefer natural remedies or herbal products, they urged caution. There is no scientific evidence that these remedies work, and they may have their own precautions or side effects.
In fact, the best remedy to combat the itch is to prevent a bite in the first place.
However, he acknowledged some people’s concerns about the ingredient’s toxicity, adding, “As with all products, I recommend treating a small area first and making sure you don’t have any allergic reactions. all use guidelines before reading and following the label.”
When to call for medical help?
You should also consult a doctor if you plan to travel to a country where blood-borne pathogens such as Zika virus and malaria are common. Mosquitoes can spread some diseases from person to person, but a doctor can advise whether vaccines or preventative treatments are available.