New Voices - About the Research - Mercy Borbor-Cordova

Seeking human and environmental health solutions in a global context

Mercy Borbor-Cordova and Mary Hayden worked with the local population to survey areas of Guayaquil, Ecaudor, with a high incidence of dengue fever. Note the barrels of standing water. (Image courtesy Mercy Borbor-Cordova.)

Megacities, pollution, and health

With Patricia Romero Lankao and Olga Wilhelmi of NCAR, Borbor-Cordova is studying the interactions among air pollution, heat waves, and vulnerability in four megacities: Bogotá, Buenos Aires, Mexico City, and Santiago de Chile. The goal is to pinpoint the worst of the worst: the poorest neighborhoods in the path of the greatest pollution.

Seventy-five percent of Latin Americans live in cities with populations over 10 million, so the researchers had many choices. The cities they picked already have data sets on air pollution, socioeconomic distribution, and other relevant factors, plus another critical asset: experienced local researchers. Three or four scientists from each country are involved in the study, and "the leaders of these national groups are very experienced people . . . who already have contacts in the policy area," says Borbor-Cordova. The national groups will be responsible for creating networks and making contacts with public health and environmental authorities.

The research team held a workshop to hash out how to standardize the information from each country. They're also conducting spatial analyses; "every city has a different way to monitor . . . environmental, health and vulnerability data," she says. Borbor-Cordova's job is to pull together the health data. The project is funded by the Interamerican Institute for Global Change Research in Brazil and is a follow-up to a previous project called South American Emissions, Megacities and Climate, which developed emissions inventories and climate change scenarios.

Dengue fever and climate change

Another project just under way studies the spread of dengue fever in Ecuador. This disease—almost unknown in developed countries—is carried by the Aedes aegypti mosquito and is found where there are warm temperatures and clean, stagnant water in which the insects lay their eggs. Most people recover from most forms of the disease, but hemorrhagic dengue can have fatal complications, particularly among children and the elderly.

To begin discerning what social and ecological factors are important in dengue transmission, Borbor-Cordova and Mary Hayden (NCAR) went to Ecuador last summer to do a pilot study of two communities with different rates of infection.

Both neighborhoods have water lines, so Borbor-Cordova was surprised to find that most residents stored water. They do this in case the piped-in water breaks down. "They use all kind of containers, from cisterns to the smallest containers, and they don't see it as a risk," she says. "But if there is even just a little amount of humidity, the pupae of Aedes mosquitoes will be there." Borbor-Cordova is working on recommendations for a health education campaign in the communities to raise awareness of this problem and its solutions.

Since their pilot study, Borbor-Cordova and Hayden have joined with an NCAR interdisciplinary research group to work on a proposal to study how climate change will affect the spread of dengue, not only in the city but upwards into the Andes mountains. "At some point the climate will be getting warmer at higher elevations, so the habitat for mosquitoes will also expand. Thus we need to determine how weather, climate, and land use would change under various projections for climate change." Ecuador is particularly well suited for this study because its population centers range in altitude from sea level, where Aedes aegypti is abundant and dengue is widespread, to higher elevations where the insect is absent and the disease currently does not occur.

Widening the circle of collaborators

A group from Borbor-Cordova's former university in Ecuador is collaborating on this project, as are public health and malaria control officials. "It would be impossible to do that work without their help," she says. If the proposal is funded, researchers will include Mexican and Colombian nationals who work on dengue fever and climate modelers from NCAR in a team that will be more interdisciplinary than most. Borbor-Cordova admits that working in such a diverse group is difficult. "For example, in my case I'm an environmental scientist and I have to learn a lot about epidemiology." Yet she stresses that it's the only way to tackle this extensive and complex problem.

The dengue initiative is at the interface of environment and public health, like Borbor-Cordova's previous work on air pollution and health in Guayaquil. Does that mean she'll organize this research in the same way? Not exactly. Borbor-Cordova has learned that each problem requires an individual approach that takes into account best practices as well as the nature of the affected population. For example, part of the success of the Guayaquil project came from the impoverished communities themselves, but to attack a mosquito-borne disease, "a top-down approach is important to complement the mosquito control in the community." That's what's worked in other places like Puerto Rico and Cuba, she says.