On this episode of Meet The Scientists, we’ll meet Mari Kimura, a scientist at the Cornell Lab of Ornithology who’s studying avian malaria, a disease that affects birds throughout the world and is spread by mosquitoes. My name is Mari Kimura, I study avian malaria. Avian malaria is caused by a tiny little parasite that infects the red blood cells of birds. The way parasites move from one bird to another is through the bite of a mosquito. The mosquito picks up the parasite when it feeds on the blood of an infected bird. When the mosquito feeds again it can pass the parasite on to another bird. While some birds that carry avian malaria can remain healthy many become weak and may eventually die. There’s a very good chance that a bird that you see your feeder might be infected avian malaria. This doesn’t necessarily mean that the bird is sick in fact it’s probably healthy if it’s still alive. Humans cannot be infected with avian malaria. Even though avian malaria can’t infect humans other parasites can. In fact it was Mari’s own experience with an infection that made her really interested in parasites and how they work. I spent some time in Africa and I was infected with a blood parasite and one of the nice things that it does is actually shows up in your eye. I just had this really uncomfortable feeling in my eye and noticed that there was a flap of… sort of this moving very slowly riding line in my eyeball which is absolutely disgusting but also completely fascinating at the same time from a biologist’s point of view. I didn’t start out wanting to study mosquitoes, in fact I resisted for a long time, but I think that mosquitoes are really really interesting. There are lots of different mosquito species we don’t really know which are responsible for transmitting avian malaria. One of the goals of my research is to answer that question. And to answer that question Mari needs to collect mosquitos she knows haven’t been infected with malaria parasites. And in order to have clean mosquitoes she needs to start at the beginning with mosquito eggs. In particular the species that I study likes to lay their eggs in tires so most of my fieldwork has really involved climbing around on tires and collecting mosquito eggs. The water that collects in these old tires is the perfect place for mosquitoes to lay their eggs in floating clusters called egg rafts. Yeah a tire pile like this is a really fantastic place for mosquitoes to lay their eggs. What I’m doing is collecting egg rafts so I see a bunch in here so I’m just gonna take my scoop. Now that she’s collected the mosquito eggs, it’s off to the insect rearing room to raise a new generation of adult mosquitoes that she can use in her experiments. So I’ve got my pan of water and I’m starting the mosquito rearing process so the first thing I want to do is set up a pan and put enough food in here for the larvae to survive until they emerge eventually as adults. This is the egg raft that we picked up from the tire, back at the tire pile, and I’m just going to dump it in here. I’m marking the pan with the species, the date, and the location. When the mosquitoes become adults she lets them feed on a bird she knows already has avian malaria. Then it’s off to the molecular lab to see if the mosquitoes have caught the parasite. So malaria parasites aren’t like birds. You can’t really look at things like color and shape and size and really say this is one species in this is another species. Because the parasites are microscopic Mari uses a high-tech process called PCR which actually allows her to separate out and see the parasites DNA if it’s there. What I’m doing is extracting DNA from the mosquito to than amplify a portion of the parasite DNA, if I find it than I know that the mosquito has been affected if the mosquito has been infected with a parasite there’s a good chance that species of mosquito might be a carrier of avian malaria out in the wild. All in all it’s this combination of field and lab work that really helps Mari to answer her scientific questions. What’s really exciting about science is that you are constantly learning new things and life is really never boring.

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Learn about Cornell scientist Mari Kimura’s work studying avian malaria, a disease that affects birds and is spread by mosquitoes, but does not affect humans.