Potential zoonotic rickettsiales bacteria associated with small mammals and their ectoparasites in africa: a systematic review and meta-analysis.

The proximity of humans to small mammals and their ectoparasites at wildlife-human interfaces in Africa creates favorable conditions for the spillover of zoonotic pathogens. Anaplasmaceae and Rickettsiaceae bacteria are emerging threats due to their genomic adaptability and resilience to environmental changes. This systematic review and meta-analysis examined the distribution and prevalence of these pathogens in African small mammals and their ectoparasites. A comprehensive search across five electronic databases yielded 37 studies meeting predefined inclusion and exclusion criteria. The most frequently reported pathogens were Rickettsia felis (11 studies), Rickettsia massiliae (8 studies), and Rickettsia typhi (7 studies). A meta-analysis using a random-effects model was conducted separately for small mammals and ectoparasites. In small mammals, the highest prevalence was observed for Anaplasma spp. (15.17%; 95% CI 8-26.9%), Rickettsia helvetica (14.65%; 95% CI 9.09-22.75%), R. felis (12%; 95% CI 6.13-22.18%), R. massiliae (10.75%; 95% CI 0.6-70.55%), and Ehrlichia spp. (10.35%; 95% CI 4.13-23.66%). Among ectoparasites, the highest prevalence was found in ticks for R. africae (41.53%; 95% CI 13.53-76.33%) and R. massiliae (30.55%; 95% CI 8.96-66.29%). In fleas, R. felis (21.68%; 95% CI 8.67-44.68%) was most prevalent. This analysis underscores the importance of molecular detection tools, such as the combination of quantitative real-time polymerase chain reaction (qPCR) and sequencing for detection and identification of Rickettsiales, and highlights the dominance of R. africae, R. felis, and R. massiliae in ectoparasites, particularly in Eastern and Northern Africa. The study also underscores the impact of sample size and geographical regional differences in prevalence estimates. This review was registered in the international database of Prospectively Registered Systematic Reviews (PROSPERO) with ID: CRD42024552324.