Seroepidemiological and biomolecular survey on Toxoplasma gondii infection on organic pig farms

Pigs are an important reservoir of Toxoplasma gondii, and pork meat is considered one of the main sources of human infection. The present survey assesses the prevalence of T. gondii in organically reared pigs in Sardinia found on the island using various diagnostic methods. Firstly, a seroepidemiological survey was carried out on 63 farms, examining individual blood samples from 414 adult pigs. Secondly, a biomolecular investigation carried out on another 62 farms, examining the brain samples from 107 adult pigs. The seroprevalence detected for T. gondii at the farm level was 85.7% (54 out of the 63 pig farms examined). However, the prevalence rate in the investigated pigs was 51.7% (214 positives out of 414 examined). A total of 54.8% (34/62) of the monitored pig farms were found to be positive by PCR. The presence of T. gondii DNA in individual brain samples was detected in 47.7% (51/107) of the examined animals. The high prevalence of T. gondii found is alarming and suggests that pigs reared on organic farms should be considered as a significant source of infection for humans in the areas investigated.