Being a Parasite Vector Isn't All Puppies and Unicorns

Maggie Koerth-Baker is a guest blogger on Boing Boing. A freelance science and health journalist, Maggie lives in Minneapolis, brain dumps on Twitter, and writes quite often for mental_floss magazine.

Short, but zippy, fact I found out this morning, while researching a piece on mosquitoes and malaria.

I've always sort of wondered what the interaction between mosquito and parasite is like. I've often seen the relationship described in a way that implies mosquitoes are ignorant of the larger human drama playing out in their digestive tract--as though they're basically just a parasite Fed-Ex. Sure, you're getting some bad news, but that's not really the mosquito's problem.

Turns out, though, there's some fairly decent evidence that, while not really being in the mortal danger we humans are, mosquitoes infected with malaria parasites aren't exactly the picture of insecty good health, either. I've spent most of the day talking to researchers at the Imperial College in London, the Johns Hopkins School of Public Health and the University of California Mosquito Research Program. They say that, while still controversial, there seem to be a least a couple of ways malaria bites the proboscis that feeds it.

First, infected female mosquitoes lay fewer eggs than their healthy sisters.

Second, it looks like infected mosquitoes might have trouble sucking blood. Gregory Lanzaro, Ph.D., director of the UC Mosquito Research Program, says there's been some research showing that malaria damages mosquito salivary glands, basically keeping the host from slurping down a full meal. Chronically un-satiated, the mosquito would end up having to bite more victims to get a proper dinner. That's good news for malaria, which needs a human habitat in order to grow up and reproduce. A mosquito that eats from more people is a mosquito that gives malaria a better chance of not ending up like a parasitic Peter Pan. Or, to look at it from our perspective, a mosquito that's carrying malaria is a mosquito that's more bitey and, thus, more likely to spread malaria to more people.

The mosquito POV? Probably a lot like being on a diet. Forever. Is it time to eat again yet?