Seroprevalence and genotyping of Toxoplasma gondii in horses slaughtered for human consumption in Italy

This study aimed to investigate the seroprevalence of Toxoplasma gondii–specific immunoglobulin G antibodies, to detect T. gondii DNA and to genotype the parasite in horses (N = 153) slaughtered at two plants located in a province of Northern Italy. Blood samples were collected, and sera were examined by an indirect fluorescent antibody test (cutoff titer, ≥1:20). Portions of tongue, masseter muscle, and heart from seropositive horses were used for nested polymerase chain reaction (PCR). Genotyping of T. gondii DNA from nested PCR–positive tissues was performed by PCR-restriction fragment length polymorphism of 13 markers. Seropositivity for T. gondii was detected in 17.6% of slaughtered horses. Prevalence was higher in females than in males and in older (aged >9 years) than in younger horses. Grade horses were statistically more likely to be infected than purebred ones. Three (11.1%) randomly chosen heart samples harbored T. gondii DNA. Polymerase chain reaction-restriction fragment length polymorphism analysis showed type I, mixed II/III, and III genotypes. Our results suggest that consumption of raw or undercooked meat from horses slaughtered in the study area may represent a potential source for human and animal infection with T. gondii in Italy.