Genomic history of the seventh pandemic of cholera in Africa

10 November 2017   Vol 358, Issue 6364

Genomic history of the seventh pandemic of cholera in Africa
By François-Xavier Weill, Daryl Domman, Elisabeth Njamkepo, Cheryl Tarr, Jean Rauzier, Nizar Fawal, Karen H. Keddy, Henrik Salje, Sandra Moore, Asish K. Mukhopadhyay, Raymond Bercion, Francisco J. Luquero, Antoinette Ngandjio, Mireille Dosso, Elena Monakhova, Benoit Garin, Christiane Bouchier, Carlo Pazzani, Ankur Mutreja, Roland Grunow, Fati Sidikou, Laurence Bonte, Sébastien Breurec, Maria Damian, Berthe-Marie Njanpop-Lafourcade, Guillaume Sapriel, Anne-Laure Page, Monzer Hamze, Myriam Henkens, Goutam Chowdhury, Martin Mengel, Jean-Louis Koeck, Jean-Michel Fournier, Gordon Dougan, Patrick A. D. Grimont, Julian Parkhill, Kathryn E. Holt, Renaud Piarroux, Thandavarayan Ramamurthy, Marie-Laure Quilici, Nicholas R. Thomson
Science10 Nov 2017 : 785-789 Full Access
Multiple waves of local outbreaks and pandemic cholera indicate independence from climate change and marine reservoirs.
Editor’s Summary
The cholera pathogen, Vibrio cholerae, is considered to be ubiquitous in water systems, making the design of eradication measures apparently fruitless. Nevertheless, local and global Vibrio populations remain distinct. Now, Weill et al. and Domman et al. show that a surprising diversity between continents has been established. Latin America and Africa bear different variants of cholera toxin with different transmission dynamics and ecological niches. The data are not consistent with the establishment of long-term reservoirs of pandemic cholera or with a relationship to climate events
The seventh cholera pandemic has heavily affected Africa, although the origin and continental spread of the disease remain undefined. We used genomic data from 1070 Vibrio cholerae O1 isolates, across 45 African countries and over a 49-year period, to show that past epidemics were attributable to a single expanded lineage. This lineage was introduced at least 11 times since 1970, into two main regions, West Africa and East/Southern Africa, causing epidemics that lasted up to 28 years. The last five introductions into Africa, all from Asia, involved multidrug-resistant sublineages that replaced antibiotic-susceptible sublineages after 2000. This phylogenetic framework describes the periodicity of lineage introduction and the stable routes of cholera spread, which should inform the rational design of control measures for cholera in Africa.