Fatal toxoplasmosis in Coendou spinosus from Southern Brazil: clinical, pathological, and genotype findings.

Although toxoplasmosis is well documented in New World non-human primates, data on its clinical impact and genotypic diversity in neotropical rodents remain limited. This study investigated fatal toxoplasmosis in Coendou spinosus through histopathological, immunohistochemical, and molecular analyses, with genotypic characterization of the infecting strain. Between September 2016 and October 2019, eight individuals were analyzed, including rescued animals and post-mortem cases from a local zoo in Southern Brazil. Tissue samples underwent histopathology and immunohistochemistry using anti-T. gondii antibodies, and molecular assays were conducted by nested PCR and PCR-Restriction Fragment Length Polymorphism (PCR-RFLP). Severe necrotizing lesions, especially in the central nervous system, were observed in five animals, associated with abundant bradyzoites and tachyzoites. Molecular detection confirmed T. gondii DNA in all animals, and subsequent genotyping revealed a previously undescribed atypical strain in the animal CS8. These findings demonstrate the high mortality associated with T. gondii infections, presenting documented clinical signs of toxoplasmosis in C. spinosus and highlighting its vulnerability to zoonotic pathogens, particularly due to habitat encroachment and increased interactions with humans and other wildlife.