How Tracking Cell Phones Is Aiding the Fight Against Malaria

We tend to associate the spread of malaria with virus-ridden mosquitoes carrying the disease across deserts, over mountains and beyond borders. But an international team of scientists has shown that cell phones might be a better indicator of how the parasite spreads from person to person.

By tracking the movements of cell phone users in Kenya for nearly one year, between 2008 and 2009, scientists fleshed out travel patterns of a disease that killed about 665,000 people the following year – mostly in Africa. When compared to a countrywide map of malaria infection rates, the scientists were able to infer the probability of malaria infection for each individual cell phone user, going so far as to be able to predict whether a person in a given area is more at-risk for infection during the day or at night.

"This is the frist time that such a massive amount of cell phone data – from millions of individuals over the course of a year – has been used, together with detailed infectious disease data, to measure human mobility and understand how a disease is spreading," said Harvard Public Health Professor Caroline Buckee, the lead author of the study, in a statement.

Buckee worked with scientists from Carnegie Mellon, Johns Hopkins, Oxford, the University of Florida and the National Institutes of Health on the study, which published in the journal Science last week. Malaria is highly present in sub-Saharan Africa, and cell phone usage is growing beyond 300 million subscribers on the continent.

Why track humans rather than mosquitoes? Because, as the study points out, our travel network more consistent and more connected, and human thoroughfares are denser than the parasite travel network. A project by a team at Princeton utilized a similar concept by tracking the spread of disease by mapping the movement of night lights across Africa.

What emerges is a clear picture of how the virus emerges from Lake Victoria, in Kenya’s west, and travels east towards the country’s capitol of Nairobi, branching into other villages along the way. The scientists recommend that malaria prevention campaigns focus on blocking these types of transmissions, which they call "imported infections."

One way to help curb the spread of malaria might be to send text messages to the phones of travelers coming from high-infection areas and urge them to use bed nets, the study notes. The scientists go so far as to suggest restricting travel for some people.

“Governments and other organizations have often concentrated malaria control efforts in low-infection regions,” said Amy Wesolowski, a PhD student at the Carnegie Mellon University department of engineering and public policy, in an announcement. “Those initiatives cost less and provide sense of accomplishment, but ultimately may not be successful because, in those areas, there are many travelers from high-infection areas.”