Urine circulating soluble egg antigen in relation to egg counts, hematuria, and urinary tract pathology before and after treatment in children infected with Schistosoma haematobium in Kenya.

Abstract

Abstract. A cohort of 117 school children infected with Schistosoma haematobium was followed-up after therapy with praziquantel (0, 2, 4, 6, 12, and 18 months) and various infection and morbidity parameters (egg counts, hematuria, soluble egg antigen [SEA] in urine, and ultrasonography-detectable pathology) were quantified. At the onset of the study, 97% of the children were positive for S. haematobium with a geometric mean egg count of 45.7 eggs/10 ml of urine. Eighty-one percent of the children were positive for SEA in urine with a geometric mean SEA concentration of 218.8 ng/ml of urine. Ninety-two percent and 56% of the children were microhematuria positive and macrohematuria positive, respectively. Two months after treatment, all infection and morbidity indicators had significantly decreased. Reinfection after treatment as determined by detection of eggs in urine was observed by four months post-treatment while the other parameters remained low. The clearance of SEA was slower than that of egg counts while pathology resolved at an even slower pace. Levels of SEA and egg output showed similar correlations with ultrasound detectable pathology; these correlations were better than the correlation between hematuria and pathology.

Human schistosomiasis haematobium: effective diagnosis of active infection using a pair of monoclonal antibodies against soluble egg antigen

“…In some studies, the consumption of fluid and involvement in physical exercise by the patients before urine samples are collected and examined have been shown to stabilize the egg output. However, in large studies especially within the community, using this approach would cause a logistic problem (Van Etten et al 1996;Kahama et al 1999). Several investigators reported a significant correlation between SEA levels and egg counts, hematuria, and ultrasound-detectable pathology Demerdash et al 1995;Shaker et al 1998;Kahama et al 1998;Salah et al 2000).…”

“…Unlike adult worm antigens that provide information on the worm burden, egg antigens provide information on the egg burden and are a good parameter for the assessment of pathology (Nibbeling et al 1998;1999). In S. haematobium infection, egg antigens could be demonstrated in significant amounts even when egg count levels were very low, which strongly suggests the activity of live eggs trapped in the bladder wall (Kahama et al 1999). …”

“…Thus, overall specificity of the CSA assay was estimated as 100%. Circulating SEA detection in S. haematobiuminfected patients gave a positivity rate in the 76 to 98% range in the studies of Bosompem et al (1996), Nibbeling et al (1998), and Kahama et al (1999 using anti-S. mansoni MAbs that recognized common epitopes with S. haematobium. However, Shaker et al (1998) and Salah et al (2000) raised specific MAbs against S. haematobium SEA and reached 91% positivity rate.…”

“…The detection of circulating antigens is used with the majority of studies concentrating on the detection of the adult wormderived circulating anodic antigens (CAA) and circulating cathodic antigens (CCA; Deelder et al 1989;De Jonge et al 1990;Van Lieshout et al 1992;Kremsner et al 1993Kremsner et al , 1994. Unlike adult worm antigens that provide information on the worm burden, egg antigens provide information on the egg burden and are a good parameter for the assessment of pathology (Nibbeling et al 1998;1999). In S. haematobium infection, egg antigens could be demonstrated in significant amounts even when egg count levels were very low, which strongly suggests the activity of live eggs trapped in the bladder wall (Kahama et al 1999).…”

Schistosomiasis - An Unusual Cause of Ureteral Obstruction: A Case History and Perspective

“…74 Immunodiagnostic assays have been developed to detect circulating antibodies to semi-purified or fractionated antigens [75][76][77][78][79][80][81] and parasite circulating antigens in different host body fluids. [82][83][84][85][86][87][88] Falcon assay screening test (FAST)-ELISA and immunoblot assays for specific antibodies to S. mansoni and S. haematobium adult worm microsomal antigens are highly specific for both species. 89,90 However, positive results in antibody assays do not necessarily correlate with the worm burden, as measured by egg output.…”