Ever sit at a outdoor restaurant in the evening and have one person complain about the mosquitoes while every one else has not noticed any? The reality is that some people are magnets for the pesky insects, while others repel them. The tendency to attract mosquito bites is inherited, according to new research, and based on a genetic component that attracts the blood-sucking bugs.
A small study published this past week in PLOS ONE found evidence that the reason some humans attract mosquitoes whereas others do not is a genetic component. The researchers from the London School of Hygiene & Tropical Medicine initiated their study based on an earlier research suggesting that the blood-sucking insects are attracted by body odor. The new study seems to explain that the truth is a little deeper below the skin surface, in the genes.
The researchers recruited 37 sets of twins for their mosquito bite study. The participants included 18 pairs of identical twins, who would share the same genes. It also included 19 sets of non-identical or “fraternal” female twins, who would share only 50 percent of their genes like any other sibling.
Each twin stuck one hand into the matching ends of a Y-shaped tube. The researchers released the some Aedes aegypti, mosquitoes known to spread dengue and other diseases, into the other, longer end. Each insect entering the bottom of the Y-shaped tube reached the fork in the road and had to determine which side of the Y to go up. If the human hands sitting as targets at the ends had similar attractions (odors and genes) for the bugs, roughly 50 percent of the mosquitoes would go up the tube one way, while remainder would choose the other route.
A roughly 50/50 split of where the insects went (or which hands they bit, if any) occurred when they were released in tubes with identical twins volunteering their hands in the Y. The insects were attracted equally to the hand from each twin because their genes, and attractiveness to the bugs, were the same.
When the fraternal twin placed their hands in the tubes, however, the mosquitoes displayed a marked preference for one twin over the other. That seems to indicate that the difference in their genes impacts the attractiveness of their body odor.
The researchers believe that their findings can be useful in the development of new measures that can help control the mosquito population and stop them from transmitting diseases. By investigating the genetic mechanisms that explain one person’s attractiveness to biting insects versus another person, “we can move closer to using this knowledge for better ways of keeping us safe from bites and the diseases insects can spread through bites,” noted Dr. James Logan, a senior lecturer in Medical Entomology at the school who served as the study author.
Mosquitoes are widely recognized as the deadliest animals on earth, killing approximately 725,000 people each year. The insects with the innocent sounding name—Spanish for “little fly”—carry devastating diseases. According to the U.S. Centers for Disease Control and Prevention (CDC), 40 percent of the world’s population (approximately 2.5 billion) live in mosquito-prone areas where they is a high risk of dengue transmission.
Logan expressed hope that further investigation of their research findings that the tendency to attract mosquito bites is genetic could lead to better ways of protecting people from mosquito-borne diseases. Understanding the genetic basis for variation between individuals could lead to development of better ways to control or repel them. Logan suggested that perhaps a pill could be created which will enhance the production of natural repellents by the body and replace skin lotions.
By Dyanne Weiss