Cell phone records may be a valuable source of data that if used correctly, could help control and eliminate malaria in sub-Saharan Africa, researchers from the USA and Kenya reported in the journal Science.

Even though malaria-carrying mosquitoes do not fly very far, the disease still manages to spread over very long distances. Infected humans can carry malaria to faraway places rapidly; as fast as a plane or car can take them. A significant percentage of infected humans have no symptoms; they can unwittingly be carrying the parasite during their travels and infecting hundreds of other people.

Humans do not infect other humans directly. An infected human may arrive to a new area and be bitten by an malaria-free mosquito. The human infects that mosquito. The mosquito, now infected, bites another person – and the disease spreads on and on…..

Malaria’s ability to spread rapidly makes it a challenging infection to eliminate, especially in parts of the world with limited resources for health care. Sub-Saharan Africa, where Malaria is endemic, is a huge area with very limited resources.

Of the one million people who die from malaria each year globally, 90% are children under five years of age in sub-Saharan Africa. Researchers from the Institute for Health Metrics and Evaluation, University of Washington, Seattle, USA, earlier this year revealed that malaria incidence and mortality globally was much higher than experts had thought. The disease threatens 3 billion people around the world.

A team of researchers in Kenya has demonstrated how cell phone records may be utilized to identify regions that should be targeted in order to optimize malaria control and elimination efforts.

Co-author, Andy Tatem, associate professor of geography at the University of Florida’s Emerging Pathogens Institute, said:

“Over 30 countries around the world have stated a national goal of eliminating malaria. But it’s difficult to eliminate the disease when new cases are constantly being imported.”

In order to know in detail how a disease is spreading, accurate data on where people live is essential.

Senior author, Caroline Buckee, assistant professor of epidemiology at Harvard School of Public Health, said “Figuring out where people live sounds trivial, but it’s actually a very difficult thing to do in sub-Saharan Africa.”

The population maps were provided by Tatem through his AfriPop Project which uses satellite imaging census data, as well as land cover maps to produce maps with very detailed population distribution information of sub-Saharan Africa.

A Kenyan cell phone company provided the team with its records so that they could identify the travel routes between towns and villages. The team had data on 14,816,521 anonymous cell phone users, which included their movements over a 12-month period around Kenya. Subscribers were linked to one of 11,920 cell towers located in 692 different settlements.

Each time a cell phone subscriber left his/her main place of residence, the duration of each trip and destination was calculated.

Buckee said:

“Researchers have used GPS trackers, surveys and traffic flow on highways to try to understand how people are moving, but that gave us information about a few hundred people at best. Using cellphone records gave us billions of data points.”

The researchers then applied the population and movement data to a malaria transmission model that foretells infection risks using probability mathematics.

This created a new map, showing likely predicted malaria movements between different areas in Kenya. It also showed which specific locations should be targeted for malaria control and elimination.

The authors said that by using their system and maps, anti-malaria efforts “would yield the biggest benefit nationally”.

The researchers discovered that a large part of malaria in Kenya comes from the Lake Victoria region and spreads east, mainly towards Nairobi, the country’s capital.

Justin Cohen, the senior technical adviser from the Clinton Health Access Initiative Malaria Control Team, said “Malaria control programs have very effective tools today to prevent transmission, but unfortunately, resources for implementing them are quite constrained. The technique used in this study gives us a way to optimize the impact of our limited resources”

Cell phones have become useful in reducing malaria incidence in various ways. Researchers from the Kenya Medical Research Institute-Wellcome Trust Research Program in Nairobi, Kenya, reported in The Lancet in August 2011 that daily text message reminders to health workers can improve treatment standards by nearly 25%.

Written by Christian Nordvist