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Randremanana R, Andrianaivoarimanana V, Nikolay B, Ramasindrazana B, Paireau J, Ten Bosch QA, Rakotondramanga JM, Rahajandraibe S, Rahelinirina S, Rakotomanana F, Rakotoarimanana FM, Randriamampionona LB, Razafimbia V, De Dieu Randria MJ, Raberahona M, Mikaty G, Le Guern AS, Rakotonjanabelo LA, Ndiaye CF, Rasolofo V, Bertherat E, Ratsitorahina M, Cauchemez S, Baril L, Spiegel A, Rajerison M. Epidemiological characteristics of an urban plague epidemic in Madagascar, August-November, 2017: an outbreak report. Lancet Infect Dis 2019; 19:537-545. [PMID: 30930106 PMCID: PMC6483974 DOI: 10.1016/s1473-3099(18)30730-8] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/01/2018] [Accepted: 11/21/2018] [Indexed: 01/14/2023]
Abstract
BACKGROUND Madagascar accounts for 75% of global plague cases reported to WHO, with an annual incidence of 200-700 suspected cases (mainly bubonic plague). In 2017, a pneumonic plague epidemic of unusual size occurred. The extent of this epidemic provides a unique opportunity to better understand the epidemiology of pneumonic plagues, particularly in urban settings. METHODS Clinically suspected plague cases were notified to the Central Laboratory for Plague at Institut Pasteur de Madagascar (Antananarivo, Madagascar), where biological samples were tested. Based on cases recorded between Aug 1, and Nov 26, 2017, we assessed the epidemiological characteristics of this epidemic. Cases were classified as suspected, probable, or confirmed based on the results of three types of diagnostic tests (rapid diagnostic test, molecular methods, and culture) according to 2006 WHO recommendations. FINDINGS 2414 clinically suspected plague cases were reported, including 1878 (78%) pneumonic plague cases, 395 (16%) bubonic plague cases, one (<1%) septicaemic case, and 140 (6%) cases with unspecified clinical form. 386 (21%) of 1878 notified pneumonic plague cases were probable and 32 (2%) were confirmed. 73 (18%) of 395 notified bubonic plague cases were probable and 66 (17%) were confirmed. The case fatality ratio was higher among confirmed cases (eight [25%] of 32 cases) than probable (27 [8%] of 360 cases) or suspected pneumonic plague cases (74 [5%] of 1358 cases) and a similar trend was seen for bubonic plague cases (16 [24%] of 66 confirmed cases, four [6%] of 68 probable cases, and six [2%] of 243 suspected cases). 351 (84%) of 418 confirmed or probable pneumonic plague cases were concentrated in Antananarivo, the capital city, and Toamasina, the main seaport. All 50 isolated Yersinia pestis strains were susceptible to the tested antibiotics. INTERPRETATION This predominantly urban plague epidemic was characterised by a large number of notifications in two major urban areas and an unusually high proportion of pneumonic forms, with only 23% having one or more positive laboratory tests. Lessons about clinical and biological diagnosis, case definition, surveillance, and the logistical management of the response identified in this epidemic are crucial to improve the response to future plague outbreaks. FUNDING US Agency for International Development, WHO, Institut Pasteur, US Department of Health and Human Services, Laboratoire d'Excellence Integrative Biology of Emerging Infectious Diseases, Models of Infectious Disease Agent Study of the National Institute of General Medical Sciences, AXA Research Fund, and the INCEPTION programme.
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Affiliation(s)
- Rindra Randremanana
- Epidemiology and Clinical Research Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | | | - Birgit Nikolay
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR 2000, CNRS, Paris, France
| | | | - Juliette Paireau
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR 2000, CNRS, Paris, France
| | - Quirine Astrid Ten Bosch
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR 2000, CNRS, Paris, France
| | | | | | | | - Fanjasoa Rakotomanana
- Epidemiology and Clinical Research Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - Feno M Rakotoarimanana
- Epidemiology and Clinical Research Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | | | - Vaoary Razafimbia
- Directorate of Health and Epidemiological Surveillance, Ministry of Public Health, Antananarivo, Madagascar
| | - Mamy Jean De Dieu Randria
- Department of Infectiology, University Hospital Joseph Raseta Befelatanana, Antananarivo, Madagascar
| | - Mihaja Raberahona
- Department of Infectiology, University Hospital Joseph Raseta Befelatanana, Antananarivo, Madagascar
| | - Guillain Mikaty
- Environment and Infectious Risks Research Unit, Laboratory for Urgent Response to Biological Threats (ERI-CIBU), Institut Pasteur, Paris, France
| | - Anne-Sophie Le Guern
- Yersinia Research Unit, National Reference Laboratory for Plague, WHO Collaborating Centre, Institut Pasteur, Paris, France
| | | | | | | | | | - Maherisoa Ratsitorahina
- Directorate of Health and Epidemiological Surveillance, Ministry of Public Health, Antananarivo, Madagascar
| | - Simon Cauchemez
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, UMR 2000, CNRS, Paris, France.
| | - Laurence Baril
- Epidemiology and Clinical Research Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar
| | - André Spiegel
- Institut Pasteur de Madagascar, Antananarivo, Madagascar
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