Half of the world's population, some 3.3 billion people, are at risk for malaria. In an effort to reduce the spread of malaria, an international team of researchers is using cell phone data to determine how human travel affects the transmission of the disease and identify regions where imported infections originate.
For the study, researchers combined a year's worth of cell phone GPS data for Kenya's nearly 15 million subscribers with maps showing malaria prevalence and estimates of infection risk. In doing so, they were able to create highly-detailed maps depicting population travel patterns to and from malaria hotspots that could be useful in shaping public health efforts to reduce infection rates. As reported in a recent Scientific American story:
The researchers found that many of the journeys, as mapped via cell phone data, involved travel to or through the capital city, Nairobi, where previous malaria eradication efforts and urbanization have pushed the illness to low levels and reduced the number of potential carrier mosquitoes. Thus, even the many visitors to the city who might be infected and city residents who have become infected while traveling to other regions are unlikely to cause a large spike in subsequent transmission of the disease there.
Many other areas of the country, however, are at higher risk from imported cases of malaria, according to the travel maps. Some of the most vulnerable places are those in the central and Lake Victoria region, which offer more potential vectors and less robust eradication progress. Those people moving within these regions, between areas where malaria has high and low prevalence, might actually be one of the biggest forces of spreading the illness.
With this information, governments could focus efforts on areas that were likely to both contribute and receive the highest number of infections. New control efforts could include boosting surveillance in these places, improving communication about risk of travel to these areas, and perhaps even sending text messages to travelers if they are visiting a high-risk region.