Evaluation of urine-circulating cathodic antigen (Urine-CCA) cassette test for the detection of Schistosoma mansoni infection in areas of moderate prevalence in Ethiopia.

ABSTRACT

OBJECTIVE: To evaluate the diagnostic performance of antigen detecting urine-CCA cassette test for the detection of Schistosoma mansoni infection in areas of moderate prevalence in Ethiopia. METHODS: Stool specimens were collected from 620 schoolchildren on three consecutive days. The samples were microscopically examined using double Kato slides; midstream urine specimens were also collected for three consecutive days and tested for S. mansoni. The sensitivity of the urine-CCA cassette test was determined using combined results of six Kato-Katz thick smears and three urine-CCA cassette tests as gold standard. The specificity of the urine-CCA cassette test was evaluated in an area where schistosomiasis is not endemic. RESULTS: Prevalence of S. mansoni infection as determined by single urine-CCA cassette test was 65.9%, by single Kato-Katz smear 37.3% and by six Kato-Katz thick smears 53.1% (P < 0.001). A single urine-CCA cassette test was significantly (P < 0.001) more sensitive (89.1%), had a lower negative predictive value (78.2%), was more accurate (92.6%) and agreed better with the gold standard (k = 0.83) than one or six Kato-Katz thick smears. However, both the Kato-Katz and urine-CCA cassette test showed 100% specificity in endemic settings. CONCLUSIONS: In moderate and high prevalence areas, urine-CCA cassette test is more sensitive than the Kato-Katz method and can be used for screening and mapping of S. mansoni infection.