The Plan

Now that I have you all hooked (or a few of you anyway), let's talk about the science!

Dengue fever is a disease caused by a virus which is carried by the mosquito Aedes aegypti. There's no vaccination and no treatment. It can sometimes lead to the more severe disease known as dengue hemorrhagic fever, which usually happens after someone has had a case of dengue fever already from one of the other serotypes. There are four serotypes.

The mosquito lives primarily in cities and breeds in artificial water containers such as water tanks, tires, buckets, and discarded trash filled with rainwater. The mosquito is also the vector for yellow fever, so there was a big push to eradicate it from the Americas in the 1950s and 1960s. But efforts waned, and rapid urbanization provided plenty of breeding grounds, and the mosquito came back in the 1970s and now covers even more area than it had inhabited before.

The point of my work this summer is to look at the distribution of the mosquito in cities in the Venezuelan Andes. We're interested in looking both between cities (what makes the cities different?) and within cities (what makes parts of the same city different from each other?). For these analyses, we'll be collecting data about the climate as well as information about population density, frequency of trash collection, and other socioeconomic variables. We're also interested in what we can learn from satellite data ("remote sensing") about city structure and its thermal properties and the change in the city over time. Oh right, and the mosquitoes.

The real work of the summer will be studying the mosquitoes. I'm going to four cities in the Andes mountain region: Mérida, Lagunillas, Barinas, and Barinitas. The first two are in the mountains, the second two in the plains next to the mountains. The first of each pair is large and the second is small. I'll have square (-ish, let's be realistic) sample sites picked out for each city, and within each "cell" we'll go door-to-door, requesting participation in the study. We have a questionnaire about household information and recent history of dengue, and then we'll survey the house and yard for larvae or potential breeding grounds.

The use of squares or cells is actually a bit new. Usually, surveyors just count 50 houses or 100 houses as they walk up a street and call it a day. However, that method doesn't work well if we want to coordinate our data with information from the satellite images. Remote sensing studies are pretty new in itself, and I think we'll be able to get a lot of information about neighborhood change and its effects on the mosquito distribution from this one in addition to the information about the effect of climate/altitude on the distribution between cities.

Well, that's a lot. So I'll leave it there for now. Let me know if there are any questions, as I could write (and have written) pages and pages more about this project.

On Thursday I leave for Mérida with Adriana, one of the lab techs here at UCV. We just purchased our flights today, which is a bit more of a last-minute approach than usual. I'll be leaving Sarah, the other public health student from Yale, here in Caracas. She's taking on the mosquitoes which carry malaria in the mangroves of the northern beaches. We used to joke at the University of Maryland about "studying beach malaria" during our vacations, and I think I'm going to let them know that it actually exists.