The serological differentiation of acute and chronic schistosomiasis japonica using IgA antibody to egg antigen

Two groups of Schistosoma japonicum infected patients (acute and chronic ) and non-infected individuals were studied using IgA antibody to egg antigen (SEA) and IgG and IgM antibodies to keyhole limpet haemocyanin (KLH). The means and standard deviation of the optical density in ELISA of acute, chronic and negative groups for IgA anti-SEA were 583±124.7, 98.2±78.8 and 82.2±39. 3, respectively. There was a statistically significance between acute patients and chronic patients (P<0.01). The means and standard deviation of IgG and IgM antibodies to KLH were 501.5±150.6, 113.0±79.1, 28.8±56.3 and 413.6±148.5, 70.2±14.8, 65.3±45.3, respectively. The detection results of IgA to SEA compared with the IgG and IgM to KLH did not demonstrate a significant difference (P>0.01). The sensitivities of IgA to SEA and IgG and IgM antibodies to KLH for the detection of acute infection were 95.24%, 90.48% and 85.71%, respectively. Therefore, this study showed that the detection of IgA to SEA is also a useful new method for the serological differentiation of acute and chronic schistosomiasis japonica in humans

The Urine Circulating Cathodic Antigen (CCA) Dipstick: A Valid Substitute for Microscopy for Mapping and Point-Of-Care Diagnosis of Intestinal Schistosomiasis

BACKGROUND The World Health Organization now recommends the provision of praziquantel treatment to preschool-aged children infected with schistosomiasis. For intestinal schistosomiasis the current operational field diagnostic standard is examination of a thick Kato-Katz smear by microscopy prepared from a single stool specimen, and although pragmatic, this methodology has well-known shortcomings. Here, as a potential alternative, the performance of the urine circulating cathodic antigen (CCA) dipstick test was assessed in terms of disease-mapping and point-of-care diagnosis for intestinal schistosomiasis in preschool-aged children. Our manuscript reports on findings at baseline and at the end of a one-year longitudinal treatment study. METHODOLOGY/PRINCIPAL FINDINGS A total of 925 children (mean age 2.8 years) were initially recruited from six lakeshore villages representative of high, moderate and low levels of disease transmission. At baseline, all children were tested for intestinal schistosomiasis by microscopic examination of duplicate Kato-Katz smears prepared from a single stool faecal, by antigen detection with the urine CCA dipstick test and by serology with a commercially available ELISA test (as 'gold-standard') that measures host antibody titres to soluble egg antigens. As a point-of-care diagnosis, the urine CCA dipstick test achieved sensitivity and specificity values ranging from 52.5-63.2% and 57.7-75.6%, respectively, with faecal microscopy achieving very high specificities (>87%) but sensitivities as low as 16.7% in the low transmission setting. CONCLUSION/SIGNIFICANCE The urine CCA test was shown to be more effective than faecal microscopy especially in lower transmission settings. The diagnostic performance of this test was not significantly impacted by treatment history or co-infections with other intestinal helminths