Occurrence of Toxoplasma gondii in Iberian pork and its association with pig seropositivity

Abstract

Pork is recognized as a major source of Toxoplasma gondii infection in humans. Although the potential association between seropositivity in white pigs and the presence of T. gondii in their meat has been investigated, corresponding information on the Iberian pig breed is still limited. In this study, we investigated the presence of T. gondii in Iberian pork and assessed its correlation with individual serological profiles to evaluate whether antibody titres can serve as indicators of meat contamination. We tested the sera of 238 Iberian pigs from three southwestern Spanish provinces (Badajoz, Cáceres, and Córdoba) using an indirect immunofluorescence assay (IFA), and analyzed matched diaphragm samples by quantitative PCR (qPCR) for T. gondii DNA detection. Serological analysis revealed an overall seropositivity rate of 46.22 %, with significant regional differences (p ≤ 0.050). Córdoba exhibited the highest seropositivity (57.89 %), followed by Cáceres (48.38 %) and Badajoz (35.71 %). Concurrently, T. gondii DNA was present in 14.29 % of the diaphragm samples, with parasite loads ranging from 78.56 to 219.09 parasites/g. A statistically significant correlation (p ≤ 0.001) was observed between grouped IFA titres (<1:20, 1:20–1:40, ≥1:80) and qPCR positivity in the corresponding diaphragm samples. Notably, the proportion of animals with titres ≥1:80 closely matched the rate of qPCR-positive meat samples. We concluded that this serological threshold can serve as an effective screening tool to discriminate animals that are at a higher risk of harboring the parasite, thereby improving food safety within the HACCP-based safety system at the slaughterhouse and in the meat industry.