Why Mosquitoes Are Attracted to Certain People, and How to Avoid Bites

Mosquitoes are selective insects, and certain factors make some people more attractive targets for bites than others. Understanding these attractants can help individuals take steps to prevent bites, especially during peak mosquito activity times.

One contributing factor is blood type. A study published in the Journal of Medical Entomology found that mosquitoes landed on individuals with Type O blood nearly twice as frequently as those with Type A. Researchers suggest this preference is linked to secretions that indicate a person's blood type, although more research is needed in this area. Jonathan F. Day, an entomology professor at the University of Florida, noted that mosquitoes are attracted to specific cues people emit.

Carbon dioxide (CO2) is a primary cue. Individuals with higher metabolic rates, due to genetics or other factors, produce more CO2, making them more attractive to mosquitoes. However, mosquitoes rely on secondary cues in addition to CO2 to identify targets. Lactic acid, which builds up in muscles during exercise, is one such secondary cue. It is released through the skin and signals to mosquitoes that a person is a potential blood source.

Mosquitoes also use their vision and detect tactile cues. They fly close to the ground and can contrast people against the horizon. Dark clothing makes individuals stand out more, attracting more mosquitoes, while lighter colors are less conspicuous. Once a mosquito lands, body heat becomes a significant tactile cue. People who naturally run warmer, meaning their blood is closer to the skin, are more likely to be bitten. Genetic or physiological differences can influence body temperature.

Lifestyle and health factors can also increase attractiveness to mosquitoes. Increased body temperature from exercise, drinking alcohol, being pregnant, or being overweight can all raise metabolic rates and make individuals more appealing. Studies have shown that consuming even one can of beer can increase a person's risk of attracting mosquitoes.

To prevent mosquito bites, avoiding peak activity times is recommended. Most mosquito species are most active at dawn and dusk. Opting for an after-work run instead of an early morning one can help avoid these times. When outdoor activities are unavoidable during these periods, covering as much skin as possible with breathable clothing, such as fishing shirts and long-legged pants, is advised.

Using insect repellent with a sufficient protection time is also effective. Sprays containing approximately 5% DEET can offer about 90 minutes of protection. The U.S. Environmental Protection Agency has concluded that normal use of DEET products is safe for adults and children. DEET is considered highly effective, particularly in areas where mosquitoes may carry diseases. It is important to follow product instructions and wash off repellent after use.

While some natural repellents like citronella candles are popular, research has not yet supported their effectiveness. Instead, creating airflow with a fan can deter mosquitoes, as they have difficulty flying in windy conditions.

If bitten, scratching the bite can worsen itching and increase the risk of infection. Applying an ice cube or an over-the-counter anti-itch cream containing hydrocortisone can help alleviate discomfort. Oral antihistamines, both drowsy and non-drowsy options, can also counteract the body's reaction to mosquito saliva. However, prevention remains the most effective strategy for avoiding bites.