Serological, molecular and pathological survey of Toxoplasma gondii infection in free ranging red foxes (Vulpes vulpes) from Central Italy

One-hundred ninety one sera of red foxes (Vulpes vulpes) of both genders (78 females and 113 males) were examined for antibodies to Toxoplasmag ondii using indirect immunofluorescent test (IFAT). Tissue samples of myocardium, lymph nodes and brains from seropositive animals were tested for the presence of T. gondii DNA by means of a specific Polymerase Chain Reaction (PCR) and then processed for histopathology and submitted to immunohistochemistry to detect T. gondii antigen. One-hundred and two sera (53.4%) scored positive. Of the antibody positive group, eight animals tested positive for PCR all eight from the myocardium of which one also included a positive brain. All the DNA extracts were genotyped. Histopathology showed lesions characteristic of protozoan encephalitis while immunohistochemistry did not show T. gondii 24 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 types I and III alleles) divergent from typical T. gondii strains, indicate red foxes as a sentinel of T. gondii in the environment.