Comparison of a Clinic-Based ELISA Test Kit with the Immunofluorescence Antibody Test for AssayingLeishmania infantumAntibodies in Dogs

Abstract

This study compares a rapid Immunospecific Kalazar Canine Rapid Spot IF with the gold standard test (indirect fluorescent antibody test (IFAT)) for detection ofLeishmania infantumspecific IgG serum antibodies in naturally exposed dogs. Serum samples were obtained from 89 healthy dogs and dogs affected by canine leishmaniosis (CanL). IgG-IFAT titers ≥80 were considered positive. Anti-L. infantumIgG antibodies were found in 54 samples with titers ranging from 1 : 80 to 1 : 5120. The performance of the rapid Immunospecific Kalazar was evaluated using a ROC curve. The area under the ROC curve of 0.957 was significantly different from 0.5 (), and therefore it can be concluded that the rapid Immunospecific Kalazar has the ability to distinguish canine sera with and withoutL. infantumIgG. The best performance of the test was at a cutoff >0 (sensitivity 92.6%, specificity 97%). The test can be used for disease screening if the cutoff is >0 (highest sensitivity, 92.6%) and is recommended as confirmatory test for the presence ofL. infantumIgG antibodies if the cutoff is set >2 (highest specificity, 100%).