Mobile phone data helps map malaria spread

Researchers have used data from 15 million people in Kenya to map the spread the malaria with detailed information on the regional incidence of the disease.

"This is the first 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," Professor Caroline Buckee, Harvard School of Public Health and lead author of the study, said.

"As Kenya begins to succeed in reducing malaria transmission in some areas but not others, cell-phone mapping of human movement between high and low-risk regions becomes a valuable planning tool," Professor Bob Snow, KEMRI-University of Oxford-Wellcome Trust Collaborative Programme said.

Between June 2008 and June 2009, the researchers mapped every call or text made by each of 14, 816, 521 Kenyan mobile phone subscribers to one of 11, 920 cell towers located in 692 different settlements.

Every time an individual left his or her primary settlement, the destination and duration of each journey was calculated.

Using a malaria prevalence map to estimate the disease's prevalence in each location being studied, the researchers inferred each resident's probability of being infected and the daily probability that visitors to particular areas would become infected.

"To estimate malaria's potential spread, it is important to factor in not only information about the location of the mosquitoes that carry the malaria parasite but also the behaviour of the people who might be infected," explained Buckee.

"Since many infected people have no symptoms, they can unintentionally carry the parasite during their travels and infect hundreds of others," he said.

The study enabled the researchers to build a map of parasite movements between 'source' areas, which mostly emit disease, and 'sink' areas, which mostly receive disease.

Malaria kills about 1 million people each year and threatens 40 million globally. Of those affected, 95 per cent are children under five in sub-Saharan Africa, report said.

The study was published in the journal 'Science'.