Abstract / Summary
Most Leishmania infantum infected dogs remain healthy, with low parasitic loads and negative to low antibody levels, making detection challenging. rKDDR-plus has shown outstanding diagnostic performance in ELISA but has never been tested in dogs thoroughly characterized by physical examination and routine laboratory tests. This study aimed to evaluate the diagnostic performance of rKDDR-plus ELISA in dogs with different L. infantum infection states (n = 94), classified as healthy seronegative (n = 25), healthy seropositive (n = 54), and sick (n = 15). In total, 37 seropositive dogs were classified as low and 32 as high. Diagnostic performance was evaluated in five groups: (G1) all dogs, (G2) healthy seronegative + sick (n = 40), (G3) healthy seronegative + healthy seropositive (n = 79), (G4) healthy seronegative + high seropositive (n = 57), and (G5) healthy seronegative + low seropositive (n = 62). Negative percent agreement was 100% in all groups, while positive percent agreement was perfect in G2 (100%), followed by G4 (96.88%), G1 (82.61%), G3 (77.78%), and G5 (70.27%). Accuracy ranged from 85.14% to 100%, and the area under the ROC curve (AUC-ROC) was as follows: G2 (1.000), G4 (0.978), G1 (0.951), G3 (0.937), and G5 (0.928). Agreement (kappa) was almost perfect in G2 and G4, and substantial in the remaining groups. In conclusion, rKDDR-plus ELISA shows overall good diagnostic performance.