Epidemiology of Leptospirosis in Africa: a systematic review of a neglected zoonosis and a paradigm for 'one health' in Africa

Allan, K. J. , Biggs, H. M., Halliday, J. E.B. , Kazwala, R. R., Maro, V. P., Cleaveland, S. and Crump, J. A. (2015) Epidemiology of Leptospirosis in Africa: a systematic review of a neglected zoonosis and a paradigm for 'one health' in Africa. PLoS Neglected Tropical Diseases, 9(9), e0003899. (doi:10.1371/journal.pntd.0003899) (PMID:26368568) (PMCID:PMC4569256)

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Abstract

Background Leptospirosis is an important but neglected bacterial zoonosis that has been largely overlooked in Africa. In this systematic review, we aimed to summarise and compare current knowledge of: (1) the geographic distribution, prevalence, incidence and diversity of acute human leptospirosis in Africa; and (2) the geographic distribution, host range, prevalence and diversity of Leptospira spp. infection in animal hosts in Africa. Methods Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, we searched for studies that described (1) acute human leptospirosis and (2) pathogenic Leptospira spp. infection in animals. We performed a literature search using eight international and regional databases for English and non-English articles published between January 1930 to October 2014 that met out pre-defined inclusion criteria and strict case definitions. Results and Discussion We identified 97 studies that described acute human leptospirosis (n = 46) or animal Leptospira infection (n = 51) in 26 African countries. The prevalence of acute human leptospirosis ranged from 2 3% to 19 8% (n = 11) in hospital patients with febrile illness. Incidence estimates were largely restricted to the Indian Ocean islands (3 to 101 cases per 100,000 per year (n = 6)). Data from Tanzania indicate that human disease incidence is also high in mainland Africa (75 to 102 cases per 100,000 per year). Three major species (Leptospira borgpetersenii, L. interrogans and L. kirschneri) are predominant in reports from Africa and isolates from a diverse range of serogroups have been reported in human and animal infections. Cattle appear to be important hosts of a large number of Leptospira serogroups in Africa, but few data are available to allow comparison of Leptospira infection in linked human and animal populations. We advocate a ‘One Health’ approach to promote multidisciplinary research efforts to improve understanding of the animal to human transmission of leptospirosis on the African continent. Author Summary Leptospirosis is an important bacterial zoonosis that affects people and animals worldwide. It is common in tropical areas where people and animals live in close contact, but the disease has been widely neglected in Africa. In this study we aimed to demonstrate the extent of leptospirosis in Africa and describe the diversity of the causative agent Leptospira spp. in human and animal infections across the continent. Through a systematic literature review, we identified 97 studies from 26 African countries that described human disease or animal infection and met inclusion criteria. Leptospirosis was the cause of illness in 2 3% to 19 8% of hospital patients with a fever. Where population-level data were available, leptospirosis was estimated to affect 3 to 102 people per 100,000 every year. A variety of animal hosts of Leptospira spp. were identified. Cattle were reported as carriers of a variety of serological types of Leptospira spp. infection. The role of cattle and many other different animal hosts in human disease transmission remains unclear. Our review demonstrates that leptospirosis is a substantial cause of human illness in Africa, and we recommend integration of human and animal studies in the future to help us understand the epidemiology of leptospirosis on this continent.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Cleaveland, Professor Sarah and Halliday, Dr Joanna and Allan, Dr Kathryn
Authors: Allan, K. J., Biggs, H. M., Halliday, J. E.B., Kazwala, R. R., Maro, V. P., Cleaveland, S., and Crump, J. A.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
Journal Name:PLoS Neglected Tropical Diseases
Publisher:Public Library of Science
ISSN:1935-2727
ISSN (Online):1935-2735
Copyright Holders:Copyright © 2015 The Authors
First Published:First published in PLoS Neglected Tropical Diseases 9(9):e0003899
Publisher Policy:Reproduced under a Creative Commons License
Data DOI:10.5525/gla.researchdata.191

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
573981Leptospirosis in Tanzania; a study of the role of rodents in an emerging public health problem.Sarah CleavelandWellcome Trust (WELLCOME)096400/Z/11/ZRI BIODIVERSITY ANIMAL HEALTH & COMPMED