Mapping the burden of cholera in sub-Saharan Africa

Author: Gene Stowe

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Sean Moore, a research assistant professor in the Department of Biological Sciences and the Eck Institute for Global Health, has coauthored a paper mapping the incidence of cholera in Africa, a critical step in the World Health Organization’s goal of reducing cholera deaths by 90 percent over the next decade.

“Mapping the burden of cholera in sub-Saharan Africa and implications for control: an analysis of data across geographical scales” appeared in The Lancet on March 1, 2018.

The mapping enables targeted application of cholera elimination strategies to high-incidence areas for most immediate and effective control. Reports often aggregate cases for a whole country and do not identify high-incidence areas within the country.

“We need a better understanding of where the current cholera burden is highest so we can target prevention and control efforts. This burden estimate can also serve as a baseline so we can compare results moving forward,” Moore says. “You don’t know how good an intervention is unless you know where you started.”

Long-term solutions to cholera include access to clean water, effective sanitation, and improved hygiene. Recently developed low-cost vaccines protect users for three to five years and provide the possibility of disease reduction while appropriate infrastructure is established. Outside of recent epidemics in Haiti and Yemen, most reported cholera outbreaks and epidemics occur in Africa.

Moore and the other researchers gathered data from government agencies, WHO, and nongovernmental organizations such as Doctors Without Borders and UNICEF to map incidence from 2010 to 2016 in a grid of 20 by 20 kilometer cells. They estimated that 151 of 3,751 districts are at high risk of cholera, totaling 87 million people. Because vaccinating that many people would require more than 160 million doses of vaccine – and annual production only recently reached 20 million doses – fine-tuned targeting among those districts is necessary. They concluded that targeting districts that account for less than 4 percent of the population could eliminate half the cholera in the region. The vaccines have been used only during outbreaks and at high-risk refugee camps in the past.

Co-authors of the study include Justin Lessler, Francisco J. Luquero, Heather S. McKay, Elizabeth C. Lee, and Andrew S. Azman, Johns Hopkins Bloomberg School of Public Health; Rebecca Grais, Epicentre; MyriamHenkens, Medecins Sans Frontieres International Office; Martin Mengel, Agence de Medecine Preventive; Jessica Dunoyer, UNICEF West and Central Africa Regional Office; Maurice M’bangombe, Malawi Ministry of Health; MamoudouHarounaDjingarey, WHO Office for Africa; Bertrand Sudre, European Centre for Disease Prevention and Control; DidierBompangue, Ministry of Health, Kinshasa; Robert S. M. Fraser, International Federation for the Red Cross and Red Crescent Societies; AbdinasirAbubakar, WHO Office for the Eastern Mediterranean; and William Perea and Dominique Legros, WHO Geneva.

The Bill and Melinda Gates Foundation provided funding for the project.

Originally published by Gene Stowe at on March 02, 2018.