New research that combines cell phone data with the incidence of malaria in Kenya has revealed how human travel patterns contribute to the spread of the disease.
The findings of a team from the Harvard School of Public Health and seven other institutions determined that malaria most likely emanates from Kenya’s Lake Victoria region and then spreads east, chiefly towards the capital of Nairobi.
“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,” senior author Caroline Buckee, an HSPH assistant professor of epidemiology, said.
Buckee said that to map malaria’s potential spread, it is important to factor in the behavior of the people who might be infected, not just information about the mosquito population. Because many infected people have no symptoms, they can carry the parasite throughout the country and infect others.
The team mapped every call or text made by every one of more than 14 million Kenyan mobile phone users to one of 11,920 cell towers located in nearly 700 settlements. Every time someone left their primary settlement, the destination and duration of the journey was calculated. The results were placed against a 2009 malaria prevalence map and researchers were then able to calculate the probability that visitors to a particular area would become infected.