Detection of Toxoplasma gondii DNA in horse meat from supermarkets in France and performance evaluation of two serological tests.
Bottom Line: In France, some cases of severe toxoplasmosis have been linked to the consumption of horse meat that had been imported from the American continent where atypical strains of Toxoplasma gondii are more common than in Europe.We performed magnetic-capture polymerase chain reaction (MC-PCR) to detect T. gondii DNA in 231 horse meat samples purchased in supermarkets in France and evaluated the performance and level of agreement of the modified agglutination test (MAT) and enzyme-linked immunosorbent assay (ELISA) in the meat juices.However, to avoid any risk of toxoplasmosis, thorough cooking of horse meat is recommended.
Affiliation: INSERM, Univ. Limoges, CHU Limoges, UMR-S 1094, Laboratoire de Parasitologie, 87000 Limoges, France.Show MeSH
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Mentions: The ROC curves and calculations of sensitivity (Se) and specificity (Sp) allowed us to identify the most suitable cut-offs that represented the best balance between sensitivity and specificity for the two serological tests MAT and ELISA in horse meat samples (Fig. 1). The best balance between sensitivity and specificity was observed at cut-offs MAT > 0 (sensitivity of 66% and specificity of 46%), OD > 0.1015 (sensitivity of 66% and specificity of 47%), and OD > 0.1145 (sensitivity of 62% and specificity of 48%) for ELISA in horse meat samples (Fig. 1 and Table 2). The area under the ROC curve ranged from 0.52 for ELISA to 0.60 for MAT, representing an acceptable level of precision. Other ELISA cut-offs such as OD > 0.06 and OD > 0.15 were subsequently identified by crossing ROC curve results with different MAT cut-offs at > 1:10, > 1:20, and > 1:40, and were also included in our additional calculations. The serial dilutions of the positive horse serum THI1813 showed that the identified cut-off values of ELISA (OD > 0.06, OD > 0.1015, OD > 0.1145, and OD > 0.15) were consistent with the negativity limits of the positive control (data not shown).
Affiliation: INSERM, Univ. Limoges, CHU Limoges, UMR-S 1094, Laboratoire de Parasitologie, 87000 Limoges, France.