Validation of the indirect MAP1-B enzyme-linked immunosorbent assay for diagnosis of experimental Cowdria ruminantium infection in small ruminants

The major antigenic protein 1 fragment B (MAP1-B) enzyme-linked immunosorbe nt assay (ELISA) for the diagnosis of Cowdria ruminantium infections was va lidated to determine cutoff values and evaluate its diagnostic performance with sheep and goat sera. Cowdria-infected populations consisted of 48 shee p and 44 goats, while the noninfected populations consisted of 64 sheep and 107 goats. Cutoff values were determined by hue-graph receiver-operating c haracteristic (TG-ROC) curves. The cutoff value was set at 31 and 26.6% of the positive control reference samples for sheep and goat sera, respectivel y. The test's diagnostic performance was evaluated with measurements of the area under the concentration-time curve (AUC) of the ROC curves and by the valid range proportion (VRP). The AUCs were 0.978 for sheep sera and 0.989 for goat sera. The VRP for both sheep and goat sera was approximately 1.0. The intermediate range (IR), which defines results that are neither positi ve nor negative, was 0 for goat sera and 2.81 for sheep sera. In an ideal t est, the AUC and VRP would be 1.0 and the IR would be 0, In this study thes e parameters were dose to those of an ideal test. It is concluded that the MAP1-B ELISA is a useful test for the diagnosis of C. ruminantium infection in small ruminants.