The urine circulating cathodic antigen (CCA) dipstick: a valid substitute for microscopy for mapping and point-of-care diagnosis of intestinal schistosomiasis.
BACKGROUND
The World Health Organization now recommends the provision of praziquantel treatment to preschool-aged children infected with schistosomiasis. For intestinal schistosomiasis the current operational field diagnostic standard is examination of a thick Kato-Katz smear by microscopy prepared from a single stool specimen, and although pragmatic, this methodology has well-known shortcomings. Here, as a potential alternative, the performance of the urine circulating cathodic antigen (CCA) dipstick test was assessed in terms of disease-mapping and point-of-care diagnosis for intestinal schistosomiasis in preschool-aged children. Our manuscript reports on findings at baseline and at the end of a one-year longitudinal treatment study.


RESULTS
A total of 925 children (mean age 2.8 years) were initially recruited from six lakeshore villages representative of high, moderate and low levels of disease transmission. At baseline, all children were tested for intestinal schistosomiasis by microscopic examination of duplicate Kato-Katz smears prepared from a single stool faecal, by antigen detection with the urine CCA dipstick test and by serology with a commercially available ELISA test (as 'gold-standard') that measures host antibody titres to soluble egg antigens. As a point-of-care diagnosis, the urine CCA dipstick test achieved sensitivity and specificity values ranging from 52.5-63.2% and 57.7-75.6%, respectively, with faecal microscopy achieving very high specificities (>87%) but sensitivities as low as 16.7% in the low transmission setting.


CONCLUSIONS
The urine CCA test was shown to be more effective than faecal microscopy especially in lower transmission settings. The diagnostic performance of this test was not significantly impacted by treatment history or co-infections with other intestinal helminths.
Disease Control Strategy Group, Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
José Carlos
JC
Sousa-Figueiredo
Martha
M
Betson
Narcis B
NB
Kabatereine
J Russell
JR
Stothard
D000909:Antibodies, Helminth / Q000097:blood; D000947:Antigens, Helminth / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D019411:Clinical Laboratory Techniques / Q000379:methods*; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000469:parasitology; D005260:Female; D006023:Glycoproteins / Q000652:urine*; D015801:Helminth Proteins / Q000652:urine*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007223:Infant; D008297:Male; D008853:Microscopy; D010274:Parasitology / Q000379:methods*; D019095:Point-of-Care Systems; D012555:Schistosomiasis mansoni / Q000175:diagnosis*; D012680:Sensitivity and Specificity
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; C091532:CCA protein, Schistosoma mansoni; D006023:Glycoproteins; D015801:Helminth Proteins