Urinary circulating DNA and circulating antigen for diagnosis of schistosomiasis mansoni: a field study

摘要

Abstract Objective To evaluate three non‐invasive assays for the diagnosis of schistosomiasis mansoni in an Egyptian village. Methods Urine was collected for the detection of circulating cathodic antigen (CCA) and cell‐free parasite DNA (cfpd) by Point‐of‐contact (POC)‐cassette assay and PCR, respectively. These tests were compared to Kato‐Katz (KK) faecal thick smear for detection of Schistosoma mansoni eggs. Results Disease prevalence by POC‐CCA assay was 86%; by PCR it was 39% vs . 27% by KK. Compared to KK, the sensitivity of POC‐CCA reached 100%, but its specificity was only 19.2% with 41% accuracy. Sensitivity of the PCR assay for cfpd was 55.56%, and specificity was 67.12% with 64% accuracy. A new end point was calculated for combined analysis of KK, POC‐CCA assay and PCR. Sensitivity for the three tests was 52.94%, 90.2% and 76.47%; specificity was 100% for KK and PCR and 18.37% for POC‐CCA. The accuracy calculated for the three tests at the end point was 76% for KK, 55% for POC‐CCA assay and 88% for PCR. Conclusion Conventional PCR assay for detection of cfpd provides a potential screening tool for intestinal schistosomiasis with reliable specificity, reasonable accuracy and affordable financial and technical cost.