An evaluation of urine-CCA strip test and fingerprick blood SEA-ELISA for detection of urinary schistosomiasis in schoolchildren in Zanzibar.
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.
Wolfson Wellcome Biomedical Laboratories, Department of Zoology, Natural History Museum, London, UK. r.stothard@nhm.ac.uk
J Russell
JR
Stothard
Jose C
JC
Sousa-Figueiredo
Claire
C
Standley
Govert J
GJ
Van Dam
Stefanie
S
Knopp
Jürg
J
Utzinger
Haji
H
Ameri
Alieppo N
AN
Khamis
I Simba
IS
Khamis
André M
AM
Deelder
Khalfan A
KA
Mohammed
David
D
Rollinson
D000293:Adolescent; D000818:Animals; D000953:Antigens, Protozoan / Q000032:analysis*; D001769:Blood / Q000469:parasitology; D002648:Child; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D011933:Reagent Kits, Diagnostic; D012548:Schistosoma haematobium / Q000302:isolation & purification*; D012553:Schistosomiasis haematobia / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D013636:Tanzania; D014556:Urine / Q000469:parasitology
D000953:Antigens, Protozoan; D011933:Reagent Kits, Diagnostic