Global analysis of Toxoplasma gondii prevalence in wild avian hosts: effects of phylogeny, ecology, and detection methods.

Abstract

Toxoplasma gondii is an Apicomplexan protozoan parasite that infects warm-blooded animals, including birds. Birds may play a significant role in the parasite's transmission due to their diverse habitats, diets, dispersal abilities, and potential as prey for predators. However, information on T. gondii infection dynamics in avian hosts is limited globally. To address this, we conducted a systematic review of 82 studies reporting T. gondii prevalence in wild birds. Using generalized linear mixed models, we analyzed global prevalence patterns across avian taxa and explored predictors of prevalence, including bird order, habitat type, trophic level, and lifestyle, in serological and direct (e.g., genetic and histological) detection studies. We also assessed the strength of the phylogenetic signal in T. gondii prevalence among avian lineages. The global distribution of studies was geographically clustered, with direct detection methods more frequently used in Europe and North America. Certain bird orders, particularly Anseriformes, Accipitriformes, and Strigiformes, exhibited higher prevalence rates, suggesting their important roles in T. gondii transmission. Ecological factors, such as habitat characteristics and trophic levels (e.g., omnivores), were significant predictors of infection. Although phylogenetic analysis revealed a weak phylogenetic signal, high prevalence values were observed in hawks, owls, and falcons. These findings consolidate existing knowledge and emphasize the importance of targeted surveillance efforts. They highlight critical gaps in research on T. gondii transmission in avian hosts and provide direction for future studies. Such insights can inform wildlife management strategies and efforts to mitigate zoonotic disease risks associated with T. gondii.