Diversity of Toxoplasma gondii strains at the global level and its determinants

The population structure of Toxoplasma gondii is characterized by contrasting geographic patterns of strain diversity at different spatial scales: global, regional and even local scales in some regions. The determinants of this diversity pattern and its possible evolutionary mechanisms are still largely unexplored. This review will focus on three main dichotomies observed in the population structure of the parasite: (1) domestic versus wild, (2) South America versus the rest of the world and (3) intercontinental clonal lineages versus regional or local clonal lineages. Here, the impact in terms of public health of this remarkably contrasting geographic diversity of T. gondii populations is discussed, with emphasis on the role of globalization of exchanges that could lead to rapid evolution of T. gondii population spatial structure and new challenges in a One Health context. •Recombination events drive the evolution of population structure of Toxoplasma gondii.•The population structure of Toxoplasma is different in wild and domestic environments.•Virulence of Toxoplasma strains in reservoir hosts influences selection of local strains.•Globalization of exchanges will impact the population structure of the parasite.•Clinicians should be aware of more pathogenic strains imported from the wild environment or from South America.