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

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.