Thanks to the collection of cholera vibrio strains from the National Reference Centre for Vibrio and Cholera (hosted by the Enteric Bacterial Pathogens Unit at the Institut Pasteur in Paris) and in collaboration with scientists from the Cantacuzino Institute (Bucharest, Romania) and the Public Health Agency of Canada, a retrospective analysis of the latest cholera epidemics in Europe, related to the current seventh pandemic, has been carried out by studying the genome of 172 strains isolated from European patients.
Understanding the origin of epidemics
In 1970, nine years after the start of the seventh cholera pandemic in Indonesia, this deadly disease reached Africa and Europe. Several southern European countries (Spain, Portugal and Italy) recorded indigenous cases in the early 1970s, and in 1974-75 all of Portugal was affected with more than 3,500 cases and 50 deaths. In France, a few sporadic cases were also reported. In Eastern Europe, cholera epidemics continued until 2011. The work of researchers has led to a better understanding of the circulation dynamics of the cholera vibrio in Europe from 1970 to 2011. Southern European countries were affected from the early 1970s by strains originating from North or West Africa, whereas Eastern European countries were affected by strains originating from South Asia, often via the Middle East, until 2011.
The 1994 epidemics in Italy and Albania are an exception, the last recorded outbreaks in Southern Europe did not originate in Africa but were linked to outbreaks in Eastern Europe.
This study confirms the role of humans in the spread of cholera
This work also showed the recurrent imported nature of cholera in Romania, which experienced four epidemics between 1990 and 1995. Each epidemic was caused by a new lineage imported from South Asia and not by the same lineage that would have persisted thanks to a permanent aquatic reservoir (a theory that has been prevalent for several years). This study, as well as a previous one on the epidemiology of cholera in Africa (2), confirmed the central role of humans in the spread of this disease, through direct or indirect human-to-human transmission.
(1) The seventh pandemic of cholera in Europe revisited by microbial genomics, Nature communications, October 22, 2020.
Mihaela Oprea1, Elisabeth Njamkepo2, Daniela Cristea1, Anna Zhukova3,4, Clifford G. Clark5, Anatoly N. Kravetz6, Elena Monakhova7, Adriana S. Ciontea1, Radu Cojocaru8, Jean Rauzier2, Maria Damian1, Olivier Gascuel3, Marie-Laure Quilici2 & François-Xavier Weill 2
1Cantacuzino National Medico-Military Institute for Research and Development, 050096 Bucharest, Romania.
2Institut Pasteur, Unité des Bactéries Pathogènes Entériques, Paris 75015, France.
3Unité Bioinformatique Evolutive, USR3756 (C3BI/DBC), Institut Pasteur & CNRS, Paris, France.
4Hub Bioinformatique et Biostatistique, USR3756 (C3BI/DBC), Institut Pasteur, Paris, France.
5National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MN, Canada.
6Kiev Research Institute of Epidemiology and Infectious Diseases, Protasiv Yar Uzuiz, Ukraine.
7Rostov-on-Don Research AntiPlague Institute, Rostov-on-Don, Russia 344002.
8National Centre for Public Health, Chisinau, Republic of Moldova
(2) Genomic history of the seventh pandemic of cholera in Africa, Science, November 10, 2017
François-Xavier Weill1,2,Daryl Domman2, Elisabeth Njamkepo1, Cheryl Tarr3, Jean Rauzier1, Nizar Fawal1, Karen H. Keddy4,5, Henrik Salje6,7, Sandra Moore8, Asish K. Mukhopadhyay9, Raymond Bercion10,11, Francisco J. Luquero12, Antoinette Ngandjio13, Mireille Dosso14, Elena Monakhova15, Benoit Garin11, Christiane Bouchier16, Carlo Pazzani17, Ankur Mutreja18,19, Roland Grunow20, Fati Sidikou21, Laurence Bonte22 , Sébastien Breurec10, Maria Damian23, Berthe-Marie Njanpop-Lafourcade24, Guillaume Sapriel25,26, Anne-Laure Page12, Monzer Hamze27, Myriam Henkens28, Goutam Chowdhury9, Martin Mengel24, Jean-Louis Koeck29, Jean-Michel Fournier30, Gordon Dougan2,18, Patrick A. D. Grimont31, Julian Parkhill2, Kathryn E. Holt32, Renaud Piarroux8, Thandavarayan Ramamurthy19, Marie-Laure Quilici1,30, Nicholas R. Thomson2,33