Accuracy of Diagnostic Tests for Schistosoma mansoni Infection in Asymptomatic Eritrean Refugees: Serology and Point-of-Care Circulating Cathodic Antigen Against Stool Microscopy

Abstract

Background: The unprecedented increase in number of African refugees arriving in Europe is confronting clinicians and general practitioners with the question of whether or not and how to screen migrants from endemic regions for Schistosoma mansoni infection.

Methods: We assessed the accuracy of 3 different diagnostic tests for S. mansoni infection (stool microscopy [samples prepared by sedimentation technique], serology, and point-of-care circulating cathodic antigen [POC-CCA] urine cassette test) in 107 newly arrived asymptomatic Eritrean refugees in Switzerland.

Result: Sixty-three study participants (59%) tested positive by at least 1 of the 3 methods. Thirty-seven participants (35%) were considered to have active schistosomiasis, either due to the detection of parasite eggs in stool and/or the presence of a concordant positive serology and urine POC-CCA test, which we consider to be a suitable surrogate marker of active infection. Of 23 microscopy-positive participants, 22 were positive by serology (95.7% sensitivity) and 21 were positive by the urine POC-CCA test (91.3% sensitivity). The combination of serology and urine POC-CCA testing detected all 23 microscopy-positive study participants (100% sensitivity).

Conclusions: With a sensitivity of 100% (95% confidence interval, 82.2%-100%), the combination of serology plus urine POC-CCA testing appears to be the most sensitive screening option for asymptomatic S. mansoni infection in Eritrean refugees, compared with stool sedimentation microscopy.

Keywords: Eritrea; POC-CCA; refugees; schistosomiasis; screening.