Evolution of Schistosoma haematobium-related pathology over 24 months after treatment with praziquantel among school children in southeastern Tanzania

• Published in: The American journal of tropical medicine and hygiene Vol. 59; no. 5; pp. 775 - 781
• Main Authors: Hatz, CF, Vennervald, BJ, Nkulila, T, Vounatsou, P, Kombe, Y, Mayombana, C, Mshinda, H, Tanner, M
• Format: Journal Article
• Language: English
• Published: Lawrence, KS ASTMH 01.11.1998; Allen Press
• Subjects: Adolescent; Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiparasitic agents; Biological and medical sciences; Child; Cohort Studies; Female; Humans; Male; Medical sciences; Parasite Egg Count; Pharmacology. Drug treatments; Praziquantel - therapeutic use; Schistosomiasis haematobia - diagnostic imaging; Schistosomiasis haematobia - drug therapy; Schistosomiasis haematobia - pathology; Schistosomicides - therapeutic use; Tanzania; Time Factors; Tropical medicine; Ultrasonography; Urinary Bladder - diagnostic imaging; Urinary Bladder - pathology; Urinary Tract - diagnostic imaging; Urinary Tract - pathology; Kenya; Africa; Sonography; Human; Urinary system disease; Schistosoma haematobium; Praziquantel; Trematode disease; Plathelmintha; Exploration; Parasitosis; Urinary tract disease; Urinary tract; Helminthiasis; Trematoda; Infection; Schistosomiasis; Chemotherapy; Treatment; Follow up study; Parasiticid; Echography; Helmintha; Evolution; Invertebrata; Child
• ISSN: 0002-9637; 1476-1645
• DOI: 10.4269/ajtmh.1998.59.775

Little is known about the dynamics of pathology due to schistosomiasis following treatment. Public health authorities in endemic areas require such information to decide on the timing of treatment and re-treatment schedules. A study to assess the rate of clearance and reappearance of pathologic lesions due to Schistosoma haematobium using ultrasound has now been carried out in two schools in southeastern Tanzania, an area of moderate-to-high transmission. Baseline data collection found urinary tract pathology in 67% of 533 children. Lesions of the bladder were significantly associated with egg positivity and microhematuria. The attributable fraction estimate of major bladder lesions due to S. haematobium was 75%. In a cohort study, 224 infected children were examined by ultrasound and then treated with a standard dose of 40 mg of praziquantel/kg of body weight. They were re-examined at two, four, six, 12, 18, and 24 months after treatment. Before treatment, 76% had pathologic lesions of the urinary tract. The proportion showing lesions decreased sharply during the first months after treatment to 11% at six months. At 24 months, lesions were detected in 57%, and 11% had developed new severe pathology. In 18 cases, pathology was present throughout, and 34 did not show any pathology throughout the study. This study provides the first detailed report on the evolution of urinary tract pathology due to S. haematobium infections at the community level. The results will help in making decisions on treatment and re-treatment schedules and more generally will provide a basis for designing control strategies in areas of moderate-to-high transmission.