A mother holds her baby as she receives a new malaria vaccine at the Walter Reed Project Research Center in Kenya, October 30, 2009.WASHINGTON — Scientists are studying the use of mobile phones to track patterns of malaria transmission in endemic nations. The research is part of an effort by many countries to control or eliminate the mosquito-borne disease.
On their own, malaria-carrying mosquitoes can’t travel very far. But the insects that are responsible for nearly one million deaths around the world each year can, and do, hitch rides in the belongings of people who travel. Malaria can also be transmitted to healthy individuals by asymptomatic people who venture from an area where many people are sick with the disease, to a location, such as a city, where residents are seldom exposed to malarial mosquitoes.
Such is the case in Kenya, where researchers have determined the disease primarily spreads east from the country’s Lake Victoria region toward Nairobi with people who travel to the country’s capital.
Their finding is based on an analysis of the mobile phone data of 15 million Kenyan subscribers, by researchers at Harvard University's School of Public Health in Boston, Massachusetts. Kenya has a population of 43 million people.
Caroline Buckee says many countries are launching aggressive efforts to eliminate malaria. One of the first steps in the campaign is to figure out how human travel patterns might be contributing to its spread.
Buckee, an assistant professor at the Harvard school, says until recently, it’s been difficult to track large population movements. Traditional methods, using census data and road networks, have not worked very well.
“But mobile phones offer a really unique way, on an unprecedented scale, to understand how a whole population is moving around,” said Buckee.
In Kenya, Buckee explains, the researchers calculated the destination and duration of each phone user's trip away from their primary home, based on transmissions to and from the mobile phone carrier’s 12,000 transmission towers.
Then, overlaying a map of malaria prevalence data in different regions of the country, researchers calculated each resident’s probability of being infected in a particular area as well as the likelihood that a visitor to that destination would become infected.
The result was a pattern showing malaria transmission routes emanating from Lake Victoria.
Buckee says having such data could influence malaria control efforts, particularly in non-endemic regions.
“One thing you could consider is sending text messages to people coming to high risk cell towers, for example, reminding them to use a bed net," she said. "And I think those types of approaches are simple but they would hopefully target people who are asymptomatic and are unaware that they are carrying parasites, reminding them that they can still contribute to malaria in that region.”
Buckee says researchers are investigating using mobile phone records in other countries to help identify malaria transmission routes, where pockets of the disease are less obvious than in Kenya.
An article on this approach is published in the journal Science.