Comparison of ELISA and urine microscopy for diagnosis of Schistosoma haematobium infection

Background: Schistosoma haematobium which causes urogenital schistosomiasis (UGS) is highly prevalent in African countries. Urine microscopy (UM) is the first-line diagnostic method of UGS. Enzyme-linked immunosorbent assay (ELISA) is a common method for screening many parasite infections primarily or alternatively. The present study established an in-house diagnostic system by ELISA and evaluated its diagnostic efficacy in comparison with UM for screening UGS in White Nile State, Republic of Sudan, 2011-2013. Methods: A total of 490 participants were screened by UM or ELISA, and 149 by both. The in-house ELISA system was established employing soluble egg antigen of S. haematobium and the cut-off absorbance was set at 0.270. Results: Of the 149 subjects, 58 participants (38.9%) were positive by UM, 119 (79.9%) were positive by ELISA and 82 (55.0%) showed consistently positive or negative results by both methods. The diagnostic sensitivity of ELISA was 94.8% and specificity was 29.7% based on UM results. The ELISA positive serum samples also cross-reacted with egg antigens of Schistosoma mansoni and Schistosoma japonicum. Conclusion: We have established in-house ELISA for screening serum immunoglobulin (Ig) G antibodies by employing soluble egg antigen of S. haematobium for diagnosis of UGS with 94.8% sensitivity and 29.7% specificity. The ELISA system can supplement the conventional diagnosis by UM.