Some people believe that mosquitoes are more attracted to people with blood group O than to any other blood type. This idea has gained traction on social media platforms, especially TikTok, where many users suggest that certain blood types act like magnets for mosquitoes.
But is there any truth to this?
First, it’s important to understand what blood groups are. There are four main blood types: A, B, AB, and O. These classifications are determined by genetic factors inherited from one’s parents and can be either Rhesus positive or negative. Blood group O is the most common among the population.
The belief that blood group O attracts mosquitoes more than others dates back to scientific studies conducted in the 1970s. One such study found that female Anopheles gambiae mosquitoes, which transmit malaria, fed more often on people with blood group O. However, this study did not provide a clear explanation, only observing the blood group distribution among mosquito-fed samples.
A later study in 2004 took a different approach. It counted the number of times mosquitoes landed on people of different blood types and found that those with blood group O experienced more landings. Still, this research did not explain why such a preference might exist. Interestingly, this study involved Aedes albopictus mosquitoes, which are known to spread diseases like dengue, zika, and chikungunya not malaria.
Another study in 2021 initially claimed that mosquitoes prefer blood group B, while blood group O was found to have high digestibility. However, the study was later retracted, casting doubt on its findings.
So, what actually attracts mosquitoes?
Experts explain that mosquitoes are not particularly concerned with blood group. Instead, they are guided by a range of other factors, the most significant of which include body odour, temperature, and carbon dioxide.
Human body odour is a result of complex compounds emitted by the skin. These can be influenced by genetics, diet, and sweat. Mosquitoes use their keen sense of smell to pick up on these chemical cues. Some of these compounds, like lactic acid, ammonia, and fatty acids, help mosquitoes zero in on a human target.
Body temperature also plays a role. Though the average human temperature is said to be 37°C, it usually ranges between 36.4°C and 37.2°C. People whose bodies are slightly warmer tend to be more attractive to mosquitoes.
Carbon dioxide is another key factor. As humans exhale, they release CO₂, which acts like a beacon for mosquitoes. The more CO₂ one produces, the more likely they are to attract mosquitoes. Interestingly, mosquitoes are able to distinguish between CO₂ from a human and that from a car or another non-living source.
Even the smell of feet can make someone more appealing to mosquitoes. This may be a strategy used by mosquitoes to bite people without waking them up, especially at night.
Regardless of blood type, there are effective ways to prevent mosquito bites. These include using insecticide-treated bed nets, applying mosquito repellents, and deploying insecticides. Additionally, new innovations such as spatial repellents devices that can be hung on a wall like photo frames are now available. These work without smoke, last for up to a month, and kill mosquitoes rather than just keeping them away.
There is also a vaccine for malaria, approved for use in children, which adds another layer of protection.
In short, while some early studies hinted at a possible link between blood group and mosquito preference, there is no strong scientific evidence that blood group O is a mosquito magnet. Other factors play a much more significant role in attracting mosquitoes.
