An evaluation of urine-CCA strip test and fingerprick blood SEA-ELISA for detection of urinary schistosomiasis in schoolchildren in Zanzibar.

Abstract

To develop better monitoring protocols for detection of urinary schistosomiasis during ongoing control interventions, two commercially available diagnostic tests - the urine-circulating cathodic antigen (CCA) strip and the soluble egg antigen enzyme-linked immunosorbent assay (SEA-ELISA) - were evaluated for detection of Schistosoma haematobium infections in 150 schoolchildren from Zanzibar. The children originated from five primary schools representative of different levels of disease endemicity across the island; using standard urine filtration assessment with microscopy, mean prevalence of S. haematobium was 30.7% (95% confidence interval (CI)=23.4-38.7%) and a total of 35.3% (95% CI=27.7-43.5%) and 8.0% (95% CI=4.2-13.6%) children presented with micro- and macro-haematuria, respectively. Diagnostic scores of the urine-CCA strip were not satisfactory, a very poor sensitivity of 9% (95% CI=2-21%) was observed, precluding any further consideration. By contrast, the performance of the SEA-ELISA using sera from fingerprick blood was good; a sensitivity of 89% (95% CI=76-96%), a specificity of 70% (95% CI=60-79%), a positive predictive value of 57% (95% CI=45-69%) and a negative predictive value of 90% (95% CI=86-98%) were found. At the unit of the school, a positive linear association between prevalence inferred from parasitological examination and SEA-ELISA methods was found. The SEA-ELISA holds promise as a complementary field-based method for monitoring infection dynamics in schoolchildren over and above standard parasitological methods.

• Authors: J Russell Stothard, Jose C Sousa-Figueiredo, Claire Standley, Govert J Van Dam, Stefanie Knopp, Jürg Utzinger, Haji Ameri, Alieppo N Khamis, I Simba Khamis, André M Deelder, Khalfan A Mohammed, David Rollinson
• Journal: Acta tropica (Acta Trop) Vol. 111 Issue 1 Pg. 64-70 (Jul 2009) ISSN: 1873-6254 [Electronic] Netherlands
• PMID: 19426665 (Publication Type: Comparative Study, Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, Protozoan
• Reagent Kits, Diagnostic

Topics

• Adolescent
• Animals
• Antigens, Protozoan (analysis)
• Blood (parasitology)
• Child
• Female
• Humans
• Immunoassay (methods)
• Male
• Molecular Diagnostic Techniques (methods)
• Reagent Kits, Diagnostic
• Schistosoma haematobium (isolation & purification)
• Schistosomiasis haematobia (diagnosis)
• Sensitivity and Specificity
• Tanzania
• Urine (parasitology)