Spotlighting zoonotic strongyloidiasis: a semi-systematic review of threadworms within baboons highlights opportunities for human infections

BACKGROUND: Both humans and non-human primates are susceptible to Strongyloides fuelleborni, a grossly underappreciated parasitic zoonotic threadworm across the world, in addition to the more widely reported Strongyloides stercoralis. This semi-systematic review sought to assess the global evidence on zoonotic strongyloidiasis in baboons, Africa's most prolific non-human primate, to better understand the zoonotic threat these animals may pose to control strategies and public health goals. METHODS: Using appropriate keyword terminology, PubMed, Scopus and Web of Science databases were searched for relevant articles, up to December 2025. Articles were then screened using inclusion and exclusion criteria, extracting relevant information for: infection prevalence, baboon species, threadworm species, infection setting and diagnostic methods. Publication content was summarised using Microsoft Excel with statistical analysis on R Studio. RESULTS: From 1588 articles [PubMed (n = 307), Scopus (n = 678) and Web of Science (n = 603)], a total of 44 were summarised. Across the six species of baboons currently recognised, infection prevalence differed significantly (P = 0.02), Papio cynocephalus with highest prevalence [68.9% (IQR 38.8-82.8)] and Papio papio with lowest [6.5% (IQR 2.5-21.8)], noting a total absence of information for Papio kindae. However, over two thirds of articles did not identify threadworm infections to species level. Although not statistically significant, infection prevalence by infection setting followed an ascending order of, research organisations [13.7% (IQR 8.0-37.3)], wild populations [26.0% (IQR 15.9-37.3)] and then zoological organisations [50.0% (IQR 31.8-75.0)]. Infection dynamics (e.g. baboon sex, age) were inadequately reported, moreover detection methods infrequently used molecular methods which hampered any precise incrimination of zoonotic transmission. CONCLUSIONS: Our semi-systematic review has revealed several gaps in the global epidemiology of zoonotic strongyloidiasis which may incur real consequences for its future elimination as a public health problem. Above all, we recommend improved threadworm species identification, particularly in population-level discrimination, to better identify transmission risks into humans. Narrowing these knowledge gaps should lead to improved future control strategies for strongyloidiasis globally.