A combination of the Kato-Katz methods and ELISA to improve the diagnosis of clonorchiasis in an endemic area, China

Examination of feces by light microscopy is widely used for specific parasitological diagnosis of clonorchiasis. However, the true incidence of infection is underestimated owing to the high missing diagnosis rate of this method. The enzyme-linked immunosorbent assay (ELISA) is widely used for the detection and control of clonorchiasis but the practicality of this method is unclear. The purpose of this study was to evaluate the effect of ELISA as a supplementary method for the diagnosis of clonorchiasis. The present study recruited 2,359 clinically suspected patients from Heilongjiang Province, China. In all, 954 cases were identified as antibody-positive by immunoglobulin (IgG)-ELISA and 495 individuals were diagnosed as egg-positive by the Kato-Katz (KK) method. The seropositive and egg-negative individuals were re-examined by repeated egg counts and/or the number of KK slides and 18 (18.18%) cases were confirmed as clonorchiasis. The 40.44%, antibody-positive rate determined by IgG-ELISA was significantly higher (P