New science explains why mosquitoes prefer some people over others 

 Summer is here, and the mosquitoes are out.

Last year the United States confirmed 664 cases of West Nile virus, which is transmitted through the tiny bloodsuckers. These cases resulted in 52 deaths, the highest number of which -- 20 -- was recorded in Texas.

So far this year, the dry heat impacting much of the West has cases down to more manageable levels. Only 11 cases and one death have been reported.

Why do mosquitos seem to prefer some people more than others?

When in groups of people, you may find that you are bitten less than if you were to confront the pesky insect alone.

Of the more than 3,500 mosquito species, only 200 of them drink human blood. Studies done on this smaller subset are attacked to specific characteristics that can lead to receiving more or fewer bites.

Carbon dioxide and blood types

With their strong olfactory senses, mosquitos can often identify the best places on the body to bite, usually the feet and ankles.

Researchers at the London School of Hygiene and Tropical Medicine found that human body odor and various chemical compounds can lead to more bites.

There are two compounds our bodies naturally create which can attract mosquitoes: carbon dioxide and lactic acid. Adults tend to get bitten more frequently than children because they emit more carbon dioxide.

Later, researchers found that parasites can change the scent of a human host, making them more susceptible to mosquitoes bites. This is especially dangerous in areas where Malaria and other disease carried by mosquitos are present.

A study from the American Journal of Entomology found slight differences in the blood type preference of mosquitos. The study tracked 300 mosquitoes; 192 were confirmed to have bit a person. Thirty percent of the insects bit someone with Type O blood.

Results from the blood type study

Source: American Journal of Entomology ·

However, the reproduction levels of the insects, represented by the number of eggs laid, were the same across all blood types.

Other studies have demonstrated the black and red tend to attract mosquitos, whereas yellow and green have been shown to keep them at bay.