Real-time PCR detection of Toxoplasma gondii in tissue samples of wild boars (Sus scrofa) from southern Italy reveals high prevalence and parasite load

BACKGROUND: Toxoplasmosis is a zoonotic parasitic disease caused by Toxoplasma gondii, a widespread protozoan in the phylum Apicomplexa. In Europe, several studies have demonstrated the presence of the parasite in tissues of wild boars (Sus scrofa), but no data exists on the T. gondii load in tissues which in turn may be an useful way to assess the infection risk for the consumer of wild boar meat. METHODS: We sampled and tested a total of 472 tissue samples of brain, heart and masseter muscle from 177 wild boars from the Campania region of southern Italy by real-time PCR analyses for detection and quantification of T. gondii. The sensitivity and specificity of the method were calculated by ROC analysis curves. RESULTS: PCR analysis revealed the presence of T. gondii in tissue samples of 78 out of 177 (44%) wild boars. In general, the brain presented the highest PCR prevalence (31%), followed by the heart (28.3%) and the masseter muscle (24.2%), with the highest estimated parasite numbers observed in the brain followed by the heart and masseter muscle. The PCR method showed an excellent discriminating ability for each of the examined tissues. According to the ROC analysis curves, the respective sensitivity and specificity were 99 and 100% for masseter muscle, 98 and 98% for brain and 96 and 98% for heart samples. CONCLUSIONS: The high prevalence of infection here detected suggests a widespread distribution of the parasite in the wildlife of the Campania region of southern Italy. The T. gondii burdens detected may potentially represent a source of infection for humans.