EPI Investigator Andy Tatem is leading a new effort to create fine-resolution population maps of Africa which will be valuable to characterizing populations at risk for diseases such as malaria. Dubbed "AfriPop," the endeavor requires massive amounts of demographic data, satellite imagery and land cover data in order to create high-resolution maps for the whole continent. And the need for continent-scaled fine-resolution maps, according to Tatem, has never been greater. Tatem and his colleagues will create fine-scale spatial demographic maps for much of Africa during the AfriPop project in order to better fight diseases such as malaria.

The world's population is expected to grow by an additional 2.7 billion people between 2005 and 2050. The fastest-growing hotspots are forecasted in urban centers of low-income countries. The social, economic and environmental repercussions of this growth could make achieving international development goals a much tougher feat. Malaria remains a large foe against development in Africa, where it is estimated that nearly 700 million people are at risk, and there are nearly 300 million clinical cases of malaria per year. The malarial cycle disrupts children's education, pulls adults away from work, weighs down local economies and human potential and even kills.

Tatem, who is an assistant professor of geography, will use a semi-automated population distribution mapping method that produces fine-scale data using a combination of settlement maps derived from satellite imagery, land cover information and census data. The best part? It costs as little as $0.01 per square kilometer. Tatem said that existing spatial demographic maps of Africa are of a poor enough quality that they are hampering researchers abilities to make confident estimates of populations at risk of contracting malaria.

This three-dimensional map of East Africa was built with a 100-meter spatial resolution, and it depicts the population distrubution for a.) Bujumbura, b.) Kigali, c.) Kampala, d.) Nairobi, and e.) Dar Es Salaam. The AfriPop project will produce similar maps for the entire African continent.

"We expect that the maps produced will have wide usage outside of the malaria field," Tatem said. "There has been a large demand from researchers for the existing East Africa maps, but the problem is that we need fine-resolution maps of much larger areas than just this one. We need not just countries but whole continents."

Tatem said that researchers at the United Nations Food and Agriculture Organization, the Centers for Disease Control and the World Bank were all showing a high demand for existing East Africa maps.

"This, combined with the President's plan for AIDS relief and the UN Platform for disaster management and emergency response, leads us to believe that there is a big need for maps like this for other areas," Tatem said.

Tatem specializes in building nuanced maps that combine models of human density and settlement patterns with epidemiological factors – such as malarial transmission rates and transportation networks --- which he combines with environmental and ecological data to model populations that are at risk for malaria or other diseases. Tatem has mapped where diseases are known to be, and where they might be in the near future given predictions about future climate change, population growth or land use change. You could say he uses satellite imagery, demographic data and environmental modeling to devise solutions for public health problems. Predictive disease risk maps can be handy tools for policy-makers and legislators seeking to decide where to invest precious dollars in prevention strategies.

Funded by $125,000 from the Philipe-Weiner Anspach Foundation, the AfriPop project began in July 2009 and will generate vital data that has been largely missing. Collaborators include Dr. Catherine Linard at the University of Oxford in the United Kingdom, the Centre for Geographic Medicine in Nairobi, Kenya and the Universite Libre de Bruxelles in Belgium. Tatem's project will also provide essential baseline data to researchers working with the Malaria Atlas Project, a project that seeks to assemble a unique spatial database of linked information based on medical intelligence and satellite-derived climate data to constrain the limits of malaria transmission and parasite prevalence.

Online resources:
AfriPop
PLoS Article
Malaria Atlas Project
Media on MAP and UF
Tatem Webpages: EPI and CLAS