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Opinions of Monday, 9 June 2014

Columnist: Anim-Mensah, Alexander

Why Mosquitoes Bite Some of Us More than Others

There are several factors why mosquitoes will like to bite some of us than others says Torah Kachur a CBC Radio's science columnist. Mosquitoes are very selective when choosing their human meal tickets, Torah went on to say. By nature mosquitoes are genetically programmed to pick up hosts with the hosts being birds, dogs, cows, and humans to name a few.
The presence of mosquitoes means intense discomfort to many of us. Generally, the male mosquitoes do not bite but for the female the reason why mosquitoes love to bite because they need blood meals to get the necessary nutrients for their larvae to mature.
There are certain groups of people mosquitoes prefers and recent studies indicate that mosquitoes prefer pregnant women as well as larger size people. They also tend to feed on adults more than they do on children. Larger size people or adults are attracted because they breathe out more carbon dioxide (CO2) than children.
Torah Kachur delves into who else is at risk of being bitten — and why
Skin and blood chemicals such as uric acid, steroids and cholesterol are attracted to mosquitoes in search of blood meal nutrients to fertilize their eggs. The reasons mosquitoes bite people with blood rich in uric acid, steroids and cholesterol.
Mosquitoes can sense victims even at about 50 m away. To find humans they are attracted to the carbon dioxide (CO2) we release through breathing, lactic acid from our sweat, as well as “nonanal” a chemical (belongs to a group called aldehyde) which every human release or excrete which generally attracts mosquitoes and bring them closer. Researchers found other indicators, however, were not enough to account for preference. Torah mentioned uric acid, cholesterol and steroids might not be the whole answer to accounts for preference which research is ongoing to reveal more.
Of interest are malaria causing mosquitoes which have shown preference to products from the bacteria on our skins. The skin houses trillions on bacteria that are important to our health and well-being. However, different people has different levels and types of skin bacteria, hence, different bacteria products and different attraction levels to malaria causing mosquitoes. Malaria causing mosquitoes are highly attracted to skins which the bacteria produces or emits sulfur containing compounds. Skins with more diverse species or types of bacteria are less attracted to the malaria mosquitoes. The foregoing paragraph does not suggest that one has to get rid of the skin bacteria to prevent attraction by mosquitoes; these skin bacteria are so important for our well-being Torah added. One can prevent mosquito attraction by using repellent which Deet Insect Repellent among others has proved to be effective.
The mystery behind mosquitoes’ attraction and repulsion was discovered by researchers at the Rockefeller University, USA. This discovery provides a clue to make mosquitoes unattractive to humans. The good news is a family of proteins known as Odorant Receptors (ORs) used by insects to smell odors responsible for the picking human smell is known which researchers has demonstrated mosquitoes’ unattractiveness to humans by genetic alteration. This alteration will make mosquitoes attractive to others except human. There is still academic discussions ongoing to determine the importance of mosquitoes and if making them unattractive toward humans will not cause any imbalance in the ecosystem since birds, other insects and others feeds on mosquitoes.

In the absence mosquitoes’ genes alteration to make humans unattractive to mosquitoes, getting rid of all unnecessary standing waters around us could provide an avenue to minimize the presence of mosquitoes. If the stagnant water could not be drained but can support aquatic life introducing mosquitoes larvae eating fish could minimize mosquito population.
Also, one can make food choices and/or lifestyle changes to prevent mosquitoes’ attractiveness. Mosquitoes are attracted to some smells as the above information points out, hence, it will not be surprising if the type of food one eats regularly could contribute to some peculiar body smell to invite mosquitoes. Apart from the smell some food choices can boost your cholesterol and uric acid levels; different foods could contain different levels of sulfur which the skin bacteria act on to produce the necessary mosquitoes’ attractive smell. Note that the presence of some sulfur compounds are associated with pungent smells such as rotten egg. I believe lifestyle and/or food choices may be a determination of what types of bacteria may be found on one’s skin. Moreover, human activities without a regular bathing routine after a hard sweaty day’s job could make one attractive to mosquitoes.
Nonanal the chemicals which the above article points out as attractive to mosquitoes are found in several perfumes and natural oils; it is unsure if the use of these perfume and/or oils on the skin could increase mosquitoes’ attractiveness.
I believe the above provides some useful information to better lives in Ghana.
God bless.

Alexander Anim-Mensah, PhD
Dayton Ohio

Below are some links in case you want to read or listen to more on this subject.