Sero-prevalence of Toxoplasma gondii in Danish pigs.

In 2015, the World Health Organisation rated toxoplasmosis as one of the most important food borne zoonotic diseases in the world. In addition, recent studies have associated Toxoplasma gondii sero-positivity with severe mental illnesses such as schizophrenia. Intake of raw or insufficiently cooked meat has been suggested to pose a major risk of T. gondii transmission in Europe. The objective of this study was to assess the T. gondii sero-prevalence in Danish pigs divided into sub populations (sows versus finishers, indoor versus outdoor). Serum samples were collected from 89 indoor-reared sows, 128 indoor finishers and 37 outdoor-reared finishers and analysed using an antibody ELISA with a sensitivity of 76.3% and a specificity of 93.7%. It was found that 33.7% indoor-reared sows, 3.1% indoor-reared finishers and 10.8% outdoor reared finishers were T. gondii sero-positive. The sero-positivity of T. gondii was significantly higher for indoor-reared sows compared to indoor-reared finishers (RR=10.9, (P<0.001). Although, the probability of T. gondii sero-positivity for outdoor-reared finishers was 3.5 times higher than for indoor-reared finishers, the difference was not statistically significant (P=0.14). The next step will be to identify specific risk factors for sero-positivity for indoor and outdoor production as well as for finishers and sows, and to use this information to help swine producers to prevent infection in their pigs.