Malaria Infected mosquitoes are more attracted to human odor than uninfected mosquitoes, speeding the transmission of malaria parasites.
Bodily odors are unpleasant enough for the people around us, but there’s a much more serious downside to our pungent aromas. Unfortunately for humans, malaria-infected mosquitoes can’t get enough of the scents we emit.
Research published in the journal PLOS ONE shows that mosquitoes infected with the malarial parasite Plasmodium falciparum are more attracted to human odors than their uninfected counterparts.
Dr. James Logan and colleagues at the London School of Hygiene & Tropical Medicine found that the malarial parasite affects mosquitoes’ olfactory systems, making human odors far more alluring to the insects. It’s good news for the mosquitoes who are getting more out of our blood, but alarming for people heading outdoors in the midst of mosquito season.
“Mosquitoes are attracted to chemicals given off in our body odours,” Logan explained in an interview with Healthline. “There are a number of chemicals, including carbon dioxide, ammonia, and carboxylic acids. Anopheles mosquitoes are particularly attracted to foot odour.”
P. falciparum is one of the parasites that changes the way disease pathogens are transmitted. It makes it so that the malaria-carrying mosquito Anopheles gambiae is better able to find blood meals, and so it facilitates the transmission of malaria from mosquitoes to humans and vice versa.
The researchers studied the behavior of mosquitoes infected with P. falciparum by putting human scent on a piece of nylon fabric and using a control cloth without human odor. When they observed the mosquitoes in a cage olfactometer, researchers saw that the infected females flocked to the human-scented fabric far more often and for longer periods of time than the uninfected mosquitoes did.
The London study is the first to show olfactory changes in mosquitoes caused by P. falciparum, but malaria is known to affect mosquito behavior in more ways than one. Researchers pointed to previous studies showing that mosquitoes infected with malaria take in larger and more frequent portions of blood than do uninfected mosquitoes.
Unfortunately, being bitten by an infected mosquito carries a high risk. As Logan explained, “if you are bitten by an infected mosquito, so long as the parasite load is high enough and at the right stage, you will become infected with malaria.”
But there are common-sense preventative measures you can take to protect yourself from mosquito bites.
“When traveling to a country with malaria you must take antimalarial medication,” Logan said. “Bed nets and repellents are also essential.”
According to the study, there are 200 million human cases and more than 770,000 deaths worldwide each year related to malaria. By understanding what mosquitoes are attracted to, we can gain greater insight into the human transmission of the disease.
This study could lead to the development of new technologies for trapping mosquitoes, particularly those infected with P. falciparum. And research is already under way to develop a vaccine to prevent the spread of this strain of malaria.
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