Disease Early-Warning Systems in Colombia

Each year in Colombia, more than 100,000 people get sick from malaria and approximately 42,000 come down with dengue fever. Now, the national government has enlisted IRI's help in using climate risk management in an ongoing project to improve its early-warning system for the two diseases. The work is overseen by the World Bank and funded by Global Environmental Facility (GEF) and Colombia.

"What makes this work fresh and exciting is its approach," says Walter Baethgen, director of IRI's Latin America and Caribbean Program. "We have here a project on climate-change adaptation, funded by a large and respected global institution, that is looking at ways to reduce a society's current vulnerabilities to climate as a means of improving its future ability to adapt. This isn't about projections fifty or hundred years from now, which mean little to people already having to deal with climate risks today."

Colombia spends $15 million annually to try to control malaria and dengue, according to Gilma Mantilla, who, until recently, ran the infectious-disease surveillance program at the Instituto Nacional de Salud (INS). Mantilla says that climate change may have profound impacts on the transmission dynamics of dengue and malaria in the country.

"For example, an increase in temperature of 2 degress Celsius, as predicted by the Intergovernmental Panel on Climate Change, could increase the number of infective mosquitoes biting humans, increase their digestion rate, and the rate at which larvae develop into adults. Scientists have found that periods of intense rainfall or drought associated with climate change increases the abundance of breeding habitats of vectors," she says. "This results in a pattern of dengue transmission that is highly associated with seasonal rainfall, especially in Colombia."

Mantilla, a physician and epidemiologist, resigned her INS post to join the latest class of students in the Earth Institute's Climate and Society Masters Program. She will spend the next year working closely with IRI scientists to move the early-warning system project forward, with the help of a fellow Colombian, Daniel Ruiz Carrascal. Ruiz graduated from the master's program this year and now is pursuing his Ph.D. at IRI. Before coming to Columbia University, he studied malaria eco-epidemiological models and several other projects in his home country aimed at understanding the potential impacts of climate variability on human health.

This international exchange and cross pollinating of ideas is a typical component of IRI projects. While the institute spends considerable resources to provide state-of-the-art climate forecasts and other information, it also helps to fund training and education of its colleagues abroad, so that the knowledge transfer remains dynamic and bidirectional.

Both Mantilla and Carrascal will head back to Colombia after completing their degrees in order to help put into practice the climate-risk-management strategies they learned here.

"Although important research on dengue and malaria early-warning systems is being carried out in other areas of the world, this project is the first to apply research to the decision-making and control activities of a national health system and to set targets for reducing of population's vulnerability to potential epidemics induced by climate change," says Mantilla.

Because of its successes with a similar project in Africa, IRI seems a natural partner for Colombia, she says. The IRI is a PAHO-WHO Collaborating Centre on early-warning systems for malaria and other climate sensitive diseases. "It can provide expert advice not only on forecasting techniques, but also on how to translate forecasts into risk assessments and how we can improve our monitoring to better inform the system," she says.

To this end, IRI sent Tony Barnston, who runs the institute's Forecast Operations group, and Steve Connor, director of both the PAHO-WHO Collaborating Centre and the IRI Environmental Monitoring Program, to Bogota in early August. There, they met with scientists from the Instituto de Hidrologia, Meteorologia y Estudios Ambientales (IDEAM), and from the INS. The scientists gave presentations on IRI's approach to climate risk management and its tools and resources, such as the freely accessible Data Library, Climate Predictability Tool and Map Rooms. Their Colombian colleagues in turn shared their knowledge on the epidemiology of malaria and dengue fever in the country, as well as giving access to their own climate and weather data.

"It was an eye opener for me to see the effects of ENSO on Colombian rainfall using a far richer network of stations than I had ever been able to access," says Barnston. "There is no substitute for visiting a country to see analyses using its local data archives first hand."

A team from Colombia is currently spending a month at IRI to be trained by Barnston and colleagues on aspects of downscaling, bias correction, multimodel ensembling and statistical inference.

Connor says his group will spend time discussing with the visitors how an early-warning system can be informed by climate and other appropriate information, to make it more 'intelligent'. "We'll be helping our partners identify ways the surveillance and response system can better respond to changing circumstances, which can affect the risk potential for epidemics and infections."

"For example, communities can become more vulnerable if, say, policies that govern access to health services change, or in the way that medicines are priced," he explains. These changes are governed by the political dynamics of the region, independent of any changes in the weather or climate, which also can raise of lower vulnerabilities, he says.

What this project comes down to in the end, says Walter Baethgen, "is going from something abstract--a data point from a model, for example--to some action that is very real and very much needed, such as a preventative spraying program or the purchasing of extra antimalarial drugs."

Relevant Links

Project description [pdf]