It’s one of life’s most maddening injustices. How is it possible that if two people enter a mosquito-infested environment, one will come out looking like a pizza while the other escapes unharmed?
There are several answers, according to research collated by the Smithsonian Institution in Washington D.C. Many relate to lifestyle: vigorous exercise builds up lactic acid and heat that makes you “stand out to insects”. Dark or vivid clothing can make you more visible, and alcohol consumption is a mooted yet unproven factor.
Mosquitoes locate their targets by smelling carbon dioxide, which is produced in higher volume by larger people and particularly pregnant women. Skin bacteria colonies are also attractive and may explain the volume of bites to feet and ankles where they are densest.
But the research finds genetics are the most important factor, explaining up to 85% of variation, proving that you can be cursed or blessed.
“We think that 10% of the population are mega-attractive and 10% completely unattractive,” Dr. James Logan, mosquito expert at the London School of Hygiene and Tropical Medicine, told Metro. “'Fruity-smelling' chemicals known as ketones are responsible," adds Logan, and “we’re working to develop a repellant based on this…we think the traits are passed genetically.”
Mosquitoes’ preference for human blood over other species may also provide a solution. Genetic engineers at the US-based Howard Hughes Medical Institute (HHMI) were recently able to reduce the preference relative to guinea pigs, reporting that by “disrupting a single gene, we can fundamentally confuse the mosquito from its task of seeking humans.”
HHMI Researcher Leslie B. Vosshall told Metro this success will lead to “new repellants”, and ultimately “make attractive people less attractive”. Until then, stay out of the swamps.