Comparison of PCR and Serologic Survey for Diagnosis of Toxoplasmosis in Sheep

Comparative diagnosis of Toxoplasma gondii infection in sheep were carried out with PCR and some serological assays using 200 blood and serum samples collected from sheep of different ages and sexes slaughtered in the main abattoir in Cairo and Giza, Egypt. PCR showed the higher prevalence of toxoplasmosis (48.5%) followed by the Modified Agglutination Test (MAT) (45.5%) and the Latex Agglutination Test (LAT) (41.0%), while the lowest prevalence was detected with the Indirect Hem-Agglutination Test (IHAT) (38.5%). When the data of the serological tests were compared with that of the PCR, as a reference test for toxoplasmosis, MAT had the highest sensitivity (95.9%) followed by LAT (90.7%) and the lowest sensitivity by IHAT (80.4%). On the other hand IHAT had the highest specificity (91.3%) followed by MAT (88.3%) and the lowest specificity was by LAT (84.5%). The present study adopt PCR and serological survey of T. gondii antibodies in sheep by using more sensitive and specific antigens prepared from isolated T. gondii local strain and the obtained results suggests that MAT alone or with LAT can be used as a highly sensitive screening test followed by PCR as a specific confirmatory test for diagnosis of toxoplasmosis in sheep. Consequently, the high prevalence of sheep toxoplasmosis detected by this study scopes the public health significance of sheep’s meat as source of human infection.