Toxoplasma gondii infection and biosecurity levels in fattening pigs and sows: serological and molecular epidemiology in the intensive pig industry (Lombardy, Northern Italy)

Toxoplasma gondii is a widespread protozoan affecting animals and humans. One of the major routes of human infection is through the consumption of raw or under-cooked meat, particularly of certain animal species, including pigs. Although T. gondii represents an important public health issue, its control at slaughter is not mandatory. Consequently, available information on T. gondii infection in domestic animals destined for human consumption is scarce. Thus, an epidemiologic survey was designed to update information on T. gondii infection in pigs from intensive production. Fattening pigs and sows from conventional farms were sampled. Sera were tested with a commercial ELISA for anti- T. gondii antibodies, whereas molecular analysis by 529 bp repetitive element PCR and B1 real-time PCR with subsequent genotyping was performed on heart samples. Statistical analysis was carried out to detect farm management features and sanitary procedures enhancing the risk of infection. At the farm level, 63.6% (7/11) of farms housing sows and 6.7% (1/15) housing fattening pigs scored positive, with individual prevalences of 8.6% (13/151) in sows and 0.5% (1/219) in fattening pigs. T. gondii DNA was detected in eight sows and one fattening pig, and sequencing revealed the presence of all three genotypes (types I, II, and III). Furthermore, the decrease in the biosecurity level enhanced the risk of infection within a farm. The present survey outcomes confirm the spread of T. gondii infection in pig farms in an area of intensive swine production. The application of stricter sanitary procedures may contribute to a further reduction of infection.