Serologic, molecular, and pathologic survey of Toxoplasma gondii infection in free-ranging red foxes (Vulpes vulpes) in central Italy.

We tested 191 sera of red foxes (Vulpes vulpes; 78 females and 113 males) for antibodies to Toxoplasma gondii using an indirect immunofluorescent test. Tissue samples of myocardium, lymph nodes, and brains from antibody-positive animals were tested for T. gondii DNA using specific PCR and processed for histopathology and immunohistochemistry (IHC) to detect T. gondii antigen. Of 192 (53.4%) antibody-positive animals, eight were positive by PCR on myocardium and one on brain. All DNA extracts were genotyped. Histopathology showed lesions characteristic of protozoan encephalitis; IHC did not show T. gondii antigen in examined tissues. The high antibody prevalence found in our study, which is the first in Italy, and the occurrence of polymorphic strains (combination of different type I and III alleles) divergent from typical T. gondii strains, suggests red foxes may be a sentinel of T. gondii in the environment.