Evaluation of Urine CCA Strips for (Field) Diagnosis of Active Schistosoma mansoni Infection in a Low Endemic Kenyan Community

Abstract

Schistosomiasis is a chronic parasitic disease caused by a digenetic trematode blood fluke of the genus Schistosoma. The disease remains a serious public health problem in endemic countries and affects at least 207 million people worldwide, with 85% in Africa. In Kenya, more than 3.5 million are infected. A definite diagnosis of the disease plays a key role in the control of schistosomiasis. The detection of Schistosome Circulating antigens is an effective approach to discriminate previous exposure and current infection. Simple, non-invasive tools for detection of S. mansoni would be highly valuable with the view of post-intervention assessment in programmes but also for treatment/re-treatment of the individual patient. The study was conducted in Makueni, a low infection area (6 to 90 years old). The prevalence was 56.4% after three consecutive Kato-Katz stools. A population sample of n= 521 individuals was selected from an initial study cohort in an epidemiological follow-up of Schistosome infections in this foci. All the subjects in the sub-sample had been treated with praziquantel 40 mg/kg. The study was to determine the prevalence of S. mansoni using Kato technique and CCA (Circulating Cathodic Antigen) urine Elisa strips at baseline and 24 hours then also at 2 years later. The cohort study population at baseline had a prevalence of 62% of the schistosomiasis infection. The detection of schistosomiasis CCA at baseline using the CCA Elisa strip on urine samples gave a prevalence of 71.9%. The CCA was determined 24 hours after treatment with PZQ and the prevalence was 44.1%. In conclusion, Kitengei village is low endemic for schistosomiasis. Finally, circulating cathodic antigen can be used as a diagnostic tool, for the follow-up of chemotherapy and re-infection and as a field test and/or screening tool in control programmes.