Systematic Review of Important Bacterial Zoonoses in Africa in the Last Decade in Light of the 'One Health' Concept

Abstract

Zoonoses present a major public health threat and are estimated to account for a substantial part of the infectious disease burden in low-income countries. The severity of zoonotic diseases is compounded by factors such as poverty, living in close contact with livestock and wildlife, immunosuppression as well as coinfection with other diseases. The interconnections between humans, animals and the environment are essential to understand the spread and subsequent containment of zoonoses. We searched three scientific databases for articles relevant to the epidemiology of bacterial zoonoses/zoonotic bacterial pathogens, including disease prevalence and control measures in humans and multiple animal species, in various African countries within the period from 2008 to 2018. The review identified 1966 articles, of which 58 studies in 29 countries met the quality criteria for data extraction. The prevalence of brucellosis, leptospirosis, Q fever ranged from 0-40%, 1.1-24% and 0.9-28.2%, respectively, depending on geographical location and even higher in suspected outbreak cases. Risk factors for human zoonotic infection included exposure to livestock and animal slaughters. Dietary factors linked with seropositivity were found to include consumption of raw milk and locally fermented milk products. It was found that zoonoses such as leptospirosis, brucellosis, Q fever and rickettsiosis among others are frequently under/misdiagnosed in febrile patients seeking treatment at healthcare centres, leading to overdiagnoses of more familiar febrile conditions such as malaria and typhoid fever. The interactions at the human-animal interface contribute substantially to zoonotic infections. Seroprevalence of the various zoonoses varies by geographic location and species. There is a need to build laboratory capacity and effective surveillance processes for timely and effective detection and control of zoonoses in Africa. A multifaceted 'One Health' approach to tackle zoonoses is critical in the fight against zoonotic diseases. The impacts of zoonoses include.

Keywords: Africa; One-health; Zoonosis; animals; antibiotics; antimicrobial resistance; bacteria; epidemiology; livestock.

Figure 1

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flowchart showing search strategy and selection process for the research articles published between 2008 and 2018 used in the current study. Based on the search strategy, 3553 English articles were identified in total. Duplicates were removed.

Figure 2

The prevalence of important bacterial zoonotic diseases in different geographic regions in Africa.

Figure 3

Geographic distribution of important bacterial zoonotic diseases between 2008 to 2018 in Africa. Map of Africa showing locations indicating countries with reported zoonotic diseases and circulation. (Map was reproduced from Nations Online Project.)