Without mosquitoes, malaria wouldn't be able to infect humans. But in addition to hitching a ride, it now appears that the parasite also alters insect behavior — making infected mosquitoes thirstier for human blood. Like, a lot thirstier.
According to a new study led by James Logan, mosquitoes (Anopheles gambiae) carrying the malaria parasite (Plasmodium falciparum) are more attracted to human body odor than uninfected ones. And in fact, they're three times more likely to be drawn towards a human scent.
And fascinatingly — if not disturbingly — malaria does this by enhancing the mosquitoes sense of smell. It's an incredible evolutionary adaptation, one that doesn't directly benefit its own reproductive fitness, but that of its transmission vector. That's nasty.
Logan and his team aren't entirely sure how malaria tweaks mosquito physiology, but they suspect an alteration somewhere in the olfactory system.
The researchers figured this out after watching infected mosquitoes go to town on smelly stockings previously worn by humans. Uninfected mosquitoes weren't nearly as drawn to them.
Each year, malaria infects over 200 million people, killing 770,000 of them. Understanding how it spreads, therefore, is of critical importance. This latest discovery could result in new attractive compounds used to improve mosquito traps.
Read the entire study at PLOS: "Malaria Infected Mosquitoes Express Enhanced Attraction to Human Odor."