Epidemiology of Intracellular Bacterial Pathogens Rickettsia spp., Borrelia spp., Coxiella spp., and Bartonella spp. in West Africa from 2000 to 2023: A Systematic Review.

Background

Intracellular bacteria such as Rickettsia spp., Borrelia spp., Coxiella spp., and Bartonella spp. cause febrile illnesses similar to malaria and arboviruses, leading to under-reporting in sub-Saharan Africa.

Methods

Following Preferred Reporting Items for Systematic Review and Meta-Analyses guidelines, we included studies on these bacteria in humans, animals, and vectors in West Africa (2000-2023). Case reports, editorials, studies on other pathogens, and coinfections were excluded. Data was retrieved from African Journals Online, Google Scholar, and PubMed (last search: December 31, 2023). The risk of bias was assessed using an adapted Cochrane RoB 2.0 tool. Data were analyzed using Excel 2016 and QGIS. A random-effects model estimated prevalence, with subgroup analysis based on country, detection method, period, and host type. Heterogeneity was measured via the I2 index (>50% indicating moderate heterogeneity). Publication bias was assessed by stratifying studies by risk of bias.

Results

Out of 27 articles included, 10 covered studies on Rickettsia spp., 5 Borrelia spp., 6 Coxiella spp., 3 Bartonella spp., and 3 both Rickettsia spp. and Coxiella spp. Among them, 10 studies focused on vectors, 5 on animals, 5 on humans, and 7 on One Health. The prevalence of Rickettsia spp. was the highest in humans, 19.46%, 95% confidence interval: [19.42-19.50]. Bartonella spp. had the highest prevalence in animals, 82.57%, 95% CI: [82.46-82.69], and vectors 37.62%, 95% CI: [37.53-37.71]. Prevalence increased significantly post 2010 (81.4%). PCR-based detection showed a higher prevalence (63%). In the risk-of-bias analysis, the quality of the studies, which were included, did not affect the results and overall validity of findings.

Conclusion

Intracellular bacteria spread widely among humans, animals, and vectors. One Health approach is essential for managing zoonotic bacterial diseases in Africa. Variation in prevalence underlines the need for methodological standardization and future research should focus on harmonizing methods by integrating molecular methods.