I woke up with a multitude of itchy red bites. And? Most likely, it’s those pesky mosquitoes that are causing the irritation. While they aren’t the sole culprits for the marks left behind, the redness is actually a reaction to the saliva from those tiny, blood-sucking insects.
Globally, there are around 3,500 mosquito species, including 36 in the UK and over 200 in the US, with only the females being the notorious bloodsuckers.
Mosquitoes are widely recognized as nuisances. Even in regions like the UK and the US, where concerns over diseases such as malaria, dengue, and Zika are minimal, it’s important to be aware of their potential threats.
However, Professor James Logan urges us to take these creatures seriously. He is the Dean of the London School of Hygiene and Tropical Medicine’s (LSHTM) School of Disease Control and the CEO of Arctech.
“As climate change progresses, more mosquitoes capable of transmitting diseases are encroaching closer to the UK and the US, including not just malaria-carrying mosquitoes but those that spread dengue as well,” he states.
“Currently, there are no active disease outbreaks, but that won’t be the case for long. It’s not a question of ‘if,’ but rather ‘when.’”
According to Logan, the US is “even further ahead” in this regard, with cases of dengue, malaria, and the West Nile virus on the rise.
In May 2025, the UK Health Security Agency reported the first detection of the West Nile virus within British mosquitoes.
Regardless of potential disease threats, mosquito bites tend to be a common nuisance every summer, with scant scientific evidence to support any immediate concerns.
In the UK, the National Health Service (NHS) has noted an uptick in visits to pages about “insect bites and stings,” indicating a rise in the number of people reporting bites in recent years.
“The warmer weather might encourage mosquito reproduction and activity, leading to more of them being around,” Logan mentions.
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Why do mosquito bites itch?
As the weather heats up, the mosquito population rises—so what makes their bites so bothersome?
It all boils down to the mosquito’s mouthparts, slender and needle-like, designed for sucking.
“Mosquitoes are drawn to your scent, warmth, and moisture. When they alight on you, they insert their mouthparts into your skin,” Logan explains. “The tip of the mouthpart navigates around, seeking a blood vessel, and once it finds one, it feeds from there.”
In the process of feeding, these unwelcome intruders inject saliva into your bloodstream to prevent clotting and numb pain, allowing them to go undetected.
However, the chemicals they inject can trigger an allergic response, resulting in those itchy red welts.
“When bitten by a particular mosquito species for the first time, the reaction is generally mild,” states Logan. “With repeated bites, your body becomes sensitized, and the reactions may become stronger. Continuous exposure can further adapt your immune system.”
Your immune system treats substances like mosquito saliva as threats, prompting white blood cells to produce antibodies. Consequently, your body reacts with redness or swelling during subsequent encounters.
This process is known as sensitization, akin to how allergies develop. Fortunately, regular exposure—termed desensitization—can reduce your response over time.
In seasonal regions, the intermittent summer exposure to mosquitoes means our bodies take longer to acclimatize.
How to keep mosquitoes at bay
Now that we’ve identified the problem, how can we prevent mosquito bites? While closing windows and donning long clothing are effective strategies, they may not be appealing during hot summer days.
You might consider installing insect screens or mosquito nets in your sleeping areas.
“Removing breeding grounds is also crucial,” Logan advises, as mosquitoes thrive in stagnant water—anything deeper than a bottle cap can serve as ideal breeding conditions. Ensure to cover water sources such as flowerpots, buckets, and bird baths, and eliminate any trash or recyclables that might gather water.
In addition, wearing insect repellents is advisable. Logan praises DEET (N,N-diethyl-M-toluamide) as “one of the best repellents available,” affirming its safety when applied according to product instructions.
If you prefer a natural alternative, consider using Lemon Eucalyptus oil, noted also as OLE or PMD. Other options include IR3535 and picaridin.
Some essential oils have shown promise; a 2023 study found that clove, cinnamon, and geraniol oils can be effective.
Despite this, Logan cautions, “reliance solely on natural solutions may not be sufficient.”
If you’re willing to invest further, consider “impregnated” clothing—this doesn’t refer to anything sensational but involves fabric treated with insect repellents or insecticides, typically permethrin.
“We also have plug-in devices that distribute pesticides throughout our homes,” Logan adds, “which can eliminate pests like spiders and flies that venture inside.”
What to do if bitten
If you’ve already fallen victim to a mosquito bite, here are some tips to manage the situation.
“The first rule is not to scratch,” Logan advises, acknowledging the challenge. “Scratching only risks infection.”
In severe cases, mosquito bites could lead to serious infections, sepsis, or even limb amputation, Logan warns.
If a bite is particularly bothersome, you may consider over-the-counter antihistamines or hydrocortisone creams, although their effectiveness can vary.
“They may work wonders for some, while others experience little relief,” he notes. “Antihistamine creams need to be applied immediately after being bitten due to the rapid production of histamine.”
“Unfortunately, many people delay addressing the bite, making timely intervention essential.”
In summary, Logan emphasizes:
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About our experts
Professor James Logan serves as the Director and Head of Disease Management at the London School of Hygiene (LSHTM). He is associated with Arctech, a spinout from LSHTM. His research focuses on using sensors, insects, and other wildlife as biosensors for disease diagnostics and developing nature-inspired tools for disease surveillance. His team was the first to identify the connection between body odor and malaria infection.
Source: www.sciencefocus.com
