July 15, 2013
Determining What Makes Us Appealing As A Mosquito Meal
Lawrence LeBlond for redOrbit.com - Your Universe Online
Have you ever awakened from a summer night in the woods, camping with friends, only to find you were the sole victim of a mosquito onslaught? Or have you returned from a hike covered in bites, yet your friends were without?
While insect repellent with DEET may offer some protection, scientists concur there is little knowledge into what truly is most-effective in fighting off a seemingly never-ending attack of mosquitoes. But in an ambitious attempt to find out why some of us are more prone to mosquito onslaughts than others, experts have sorted through the evidence to alert us on who is most susceptible to mosquito bites.
One of the most surprising discoveries came from a 2004 study. Researchers from the Institute of Pest Control Technology found a person's blood type may be the top driving factor in why they become more of a treat for mosquitoes. The group of researchers determined that people with Type O blood were nearly twice as likely to be bitten as those with Type A. Those with Type B landed somewhere in the middle. How mosquitoes pick up on this is another thing. Roughly 85 percent of people actually secrete a chemical through their skin that indicates what blood type is found within, giving mosquitoes an open invitation.
Apart from our blood, mosquitoes may also be attracted to us because of certain bacteria that naturally live on our bodies. Citing a 2011 study published in the journal PLoS ONE, Smithsonian reports having large amounts of just a few types of bacteria makes skin more appealing to mosquitoes. In humans with lots of bacteria spread over a greater diversity of bacteria species, mosquitoes became less attracted.
By digging through other research on the topic, Smithsonian also discovered a 2002 study that shows alcohol plays a big role in attractiveness to mosquitoes. Just by consuming one 12-ounce bottle of beer you are inadvertently painting a huge bulls-eye on yourself for these tiny buzzing pests. However, the initial beliefs of why this was the case -- increased ethanol excreted through sweat and/or higher body temperatures -- has not been proven and it remains a mystery as to why a nice cold beer attracts an attack.
Surprisingly, several different studies have found a link between mosquito mayhem and pregnancy. Women, who are expecting, should also expect twice as many mosquito bites as those who are fetal-free. One apparent reason is because pregnant women exhale about 21 percent more carbon dioxide and are on average 1.26 degrees Fahrenheit warmer than others.
It has been found that mosquitoes find their targets by following carbon dioxide emissions in people's breath. According to a 2007 study published in Chemical Senses, mosquitoes use their maxillary palp to detect CO2 from as far as 164 feet away. So, for those who exhale more often and with deeper breaths, mosquitoes may have another open invitation. This is one discovery that could prove why kids do not get bitten as often as adults, since children do not produce as much exhaled CO2 as adults.
While mosquitoes are attracted to us using their sense of smell, sight may also be a factor in some attacks. One medical entomologist from the University of Florida explained to NBC News in a 2011 interview that wearing highly-noticeable colors -- blacks, blues, reds -- could make us easier to spot and make us a more attractive target.
Based on a wide array of mosquito-attack factors, researchers have been looking for sure-fire natural remedies to keep mosquitoes from feeding on humans. And while a mosquito bite can be just plain annoying for many people, there are serious health implications in continuing to allow mosquitoes to have free reign on our bodies.
Recently, deadly West Nile virus (WNv) has been increasing throughout the US and the world, a disease that is easily transmissible via mosquito bites. According to the US Centers for Disease Control and Prevention (CDC), more than 30,000 people have been sickened with WNv since 1999 and some 1,200 have died.
Interestingly, when it comes to mosquitoes infected with the malaria parasite Plasmodium falciparum, some chemical reaction occurs that gives mosquitoes an increased sense of smell, allowing them to detect human odor much more keenly than non-infected mosquitoes. This evidence, which comes from researchers at the London School of Hygiene & Tropical Medicine, could also help in identifying new compounds that could be used to develop modern mosquito traps and repellents.
As for DEET, the only proven method in combating mosquito onslaughts, recent research may also offer new clues into winning the war against these incessant pests.
Researchers from the Howard Hughes Medical Institute (HHMI) recently published a study that shows how the genetically modified olfactory system of mosquitoes can change the way they respond to odors, including the smell of humans and DEET.
The researchers demonstrated that mosquitoes can be genetically manipulated using innovative techniques, which could potentially lead to a greater understanding of why mosquitoes are so attracted to us humans and also how to block that attraction.
With the latest technologies and research in hand, scientists from UK's Rothamsted Research Lab are looking into natural human repellents that have been found to not attract mosquitoes. Using chromatography to isolate these chemical markers, the team is hoping to incorporate them into advanced repellents that could make it possible for anyone to avoid the inevitable summer annoyance that is the mosquito.