Toxoplasma gondii infection in animal-friendly pig production systems

PURPOSE. Consumption of undercooked pork meat products has been considered a major risk factor for contracting toxoplasmosis in humans. Indoor farming and improved hygiene have drastically reduced Toxoplasma infections in pigs over the past decades. Whether introduction of animal-friendly production systems will lead to a reemergence of Toxoplasma infections in pigs is not yet known. Investigating this possibility was the purpose of this study. METHODS. Blood was obtained from pigs raised for slaughter and tested for Toxoplasma antibodies by using latex agglutination and indirect immunofluorescence testing, with confirmation by immunoblotting. RESULTS. None of the slaughter pigs (n = 621) from conventional farms ( n = 30) were positive, whereas 38 (2.9%) of 1295 animals from animal-friendly systems tested positive ( n = 33 farms; 13 [39%] farms positive). CONCLUSIONS. The following conclusions may be derived from this study: Conventionally ( indoors) raised pigs are free from Toxoplasma infection, and ( 2) animal-friendly production systems may lead to a reemergence of Toxoplasma infections, although many of these farms remain Toxoplasma free. Slaughterhouse monitoring of pigs from animal-friendly production systems combined with on-farm prevention strategies should be applied to ensure safety for consumers of the meat products obtained from these animals.