title: Epidemiologic application of circulating antigen detection in a recent Schistosoma mansoni focus in northern Senegal.
abstract: Quantitative enzyme-linked immunosorbent assays (ELISAs) for the detection of circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) in serum and urine were applied as an epidemiologic tool in a recent, intense focus of Schistosoma mansoni in Senegal. Both CAA and CCA in serum and CCA in urine were found in 94%, 83%, and 95%, respectively, of the population, of which 91% were positive on stool examination. Circulating antigens were also detectable in sera and urines of most egg-negative individuals. The sensitivities of the urine CCA and serum CAA ELISA were substantially higher than that of a single egg count, and increased with egg output. The CAA and CCA levels correlated well with egg counts and with each other. The age-related evolution of antigen levels followed a similar pattern as egg counts, providing supplementary evidence for a genuine reduction of worm burdens in adults in spite of the supposed absence of acquired immunity in this recently exposed community. The antigen:egg ratios decreased in adults, suggesting lower worm fecundity in children. This would be compatible with a density-dependent reduction of fecundity, but not with anti-fecundity immunity in adults that perhaps has not yet developed in this new focus.
authors.affiliation: Department of Parasitology, Medical Faculty, University of Leiden, The Netherlands.
authors.forename: K
authors.initials: K
authors.lastname: Polman
authors.forename: F F
authors.initials: FF
authors.lastname: Stelma
authors.forename: B
authors.initials: B
authors.lastname: Gryseels
authors.forename: G J
authors.initials: GJ
authors.lastname: Van Dam
authors.forename: I
authors.initials: I
authors.lastname: Talla
authors.forename: M
authors.initials: M
authors.lastname: Niang
authors.forename: L
authors.initials: L
authors.lastname: Van Lieshout
authors.forename: A M
authors.initials: AM
authors.lastname: Deelder
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000947:Antigens, Helminth / Q000097:blood* / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000469:parasitology; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010270:Parasite Egg Count; D015995:Prevalence; D012550:Schistosoma mansoni / Q000276:immunology*; D012555:Schistosomiasis mansoni / Q000097:blood / Q000453:epidemiology* / Q000652:urine; D012675:Senegal / Q000453:epidemiology; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies
chemical_list: D000947:Antigens, Helminth