Global patterns of parasite sharing among freshwater turtles

Freshwater turtles represent a highly diverse and ecologically important group, yet they are among the most threatened vertebrates worldwide due to habitat loss, overexploitation, and the introduction of non-native species. In this study, we conducted a systematic literature review, following PRISMA guidelines, to assess parasite sharing among native and non-native freshwater turtles globally, compiling data from 294 publications spanning 1939 to 2025. Our analyses, including multiple correspondence analysis (MCA) and clustering analysis, revealed that parasite communities are strongly structured by host phylogeny, biogeography, and the presence of non-native species. In North America, Asia, and South America, both native and introduced turtles share extensive parasite networks, whereas Oceania and Africa show mostly endemic, intra-native associations. Non-native species such as Trachemys scripta may act as epidemiological bridges in Europe, facilitating parasite spillover to native hosts. These findings underscore the influence of evolutionary history, species introductions, and geographic isolation on host–parasite dynamics and highlight the need for targeted monitoring and management strategies to mitigate ecological and health risks.