2008 Public Lecture Series
A R C H I V E D
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Transcript: Jan Conn
Hi, I'm Jan Conn, and I work on the evolution and ecology of mosquitoes that transmit malaria parasites. I mostly work in Latin America, although I also do some work with the mosquitoes that transmit West Nile virus in North America. The reason I'm so interested in mosquitoes
is they are absolutely fascinating; they're very complex organisms. We have very
interesting tools to study their ecology and evolution.
Most of what we're doing in the lab these days is trying to characterize mosquito populations. We're trying to determine whether we can identify them as a particular species -- if they're a member of a species complex. In some cases we've discovered new potential species and, in that case, we're looking at those populations of mosquitoes with quite a different number of what we call markers. These are molecular genes, or regions of genes that we can extract from individual mosquitoes, amplify the gene or the region and sequence, and compare the sequences of a known species with our species.
We can also use the differences we might find, in the DNA code, to develop an assay that could be used very simply, to distinguish between mosquito species. Almost all of the worst diseases -- parasitic diseases, certainly, and many of the viral diseases -- are in a band around the globe that is tropical, and a lot of that has to do simply with temperature. In Latin America, the important factor is to know whether you're living in or travelling to an endemic area.
Endemic simply means that it is the place where malaria is transmitted -- usually in Latin America seasonally, so sometimes right after the rainy season -- sometimes during the dry season, and of course seasonally in the tropics is very heterogeneous; it's not identical everywhere. You can't count on the rainy season being exactly at the same time every year, especially with the El Niņo phenomenon, and with global warming, changing weather patterns in dramatic ways regionally and continentally.
We have mosquitoes in North America that have historically transmitted malaria parasites, especially during, for instance, the American Civil War. The reason that there's so much less malaria transmitted in North America now is for a combination of reasons. Many of them have to do with the fact that we have drained a lot of swamps. People live in general in screened or air-conditioned houses, so what we've managed to do is cut the contact in many cases and places between the mosquitoes that could transmit malaria and the humans that they could transmit the parasites to.