Multiple Typing Approach to Characterize Toxoplasma gondii Strains from Captive and Livestock Species in Northern Italy Suggests the Circulation of Type-II Variants

Abstract

Toxoplasma gondii is a widespread foodborne parasite that affects both humans and animals worldwide. The genetic characterization of this parasite has become crucial due to its epidemiological and clinical implications. The present study focused on the direct genetic characterization of T. gondii-positive DNA samples from Northern Italy, using three standardized genotyping methods. Of the 87 PCR-positive DNA samples obtained from livestock, wild, and captive animals, 9 were confirmed, quantified, and subsequently subjected to typing procedures: microsatellite analysis, PCR-RFLP, and partial sequencing of GRA6 and SAG3 genes. Most of the typed samples, derived from clinical cases of toxoplasmosis, specifically related to abortion outbreaks in small ruminants, as well as one case of systemic toxoplasmosis in lemur (Lemur catta). Predominantly, Type II strains were observed, with non-clonal variants identified in a sheep and a lemur. Sequencing of SAG3 revealed specific single nucleotide polymorphism, previously documented in European type-II variants, with phylogenesis suggesting a potential genetic relatedness between T. gondii population in Italy, Spain, and France. By utilizing three distinct genotyping methods, this study provides the first comprehensive microsatellite profiles of T. gondii in Italy, and additional insights into the molecular variability of T. gondii strains circulating in this country from different epidemiological settings.