The immunofluorescence antibody test (IFAT) for the diagnosis of schistosomiasis used in a non-endemic area.
OBJECTIVE
To evaluate an immunofluorescence antibody test (IFAT) for diagnosis of schistosomiasis in nonimmune travellers and immigrants from endemic areas.


METHODS
65 patients (48 Danes and 17 immigrants) with schistosomiasis were included. The diagnosis of schistosomiasis was based on the presence of schistosome eggs in faeces, urine, sperm, rectal or bladder biopsies and/or the presence of specific antibodies determined by the serological immunofluorescence antibody test (IFAT). Egg excretion was detected using conventional methods and the IFAT performed on whole S. mansoni schistosomula worms, harvested after 8 weeks from mice. Two patterns of immunofluorescence were observed: Fluorescence in the gut of the schistosome called 'Gut Associated Antigen, GAA', and fluorescence of the surface of the schistosomula called 'Membrane Bound Antigen, MBA'.


RESULTS
Eggs were found in 44% of the Danish patients and in 76% of immigrants. The diagnosis was based on a positive IFAT in 48% of the patients. In patients from nonendemic areas, the finding of antibodies against GAA was diagnostic while optimal sensitivity in the immigrants was reached by measuring antibodies against both GAA and MBA.


CONCLUSIONS
In patients from nonendemic areas GAA is a sensitive marker of acute infection with schistosomiasis. In patients from endemic areas the demonstration of both GAA and MBA is necessary to properly identify long-lasting, nonacute infections. Egg-detection and/or measurement of CAA and CCA remain the methods of choice to monitor treatment as the immunofluorescence assay may remain positive for several years after treatment.
Tarp
B
B
Department of Infectious Diseases, Marselisborg Hospital, Aarhus, Denmark.
Black
F T
FT
Petersen
E
E
D000293:Adolescent; D000328:Adult; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D000947:Antigens, Helminth / Q000032:analysis / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003718:Denmark; D004641:Emigration and Immigration; D019353:Endemic Diseases; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D008297:Male; D008875:Middle Aged; D010270:Parasite Egg Count; D012547:Schistosoma / Q000276:immunology; D012552:Schistosomiasis / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology; D012553:Schistosomiasis haematobia / Q000175:diagnosis; D012555:Schistosomiasis mansoni / Q000175:diagnosis; D012556:Schistosomicides / Q000627:therapeutic use; D012680:Sensitivity and Specificity; D014195:Travel
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D012556:Schistosomicides