In a fishing community on Lake Albert in Uganda the pattern of intensity of Schistosoma mansoni infection 6 months after treatment with praziquantel was found to be very similar to reinfection patterns seen in previously studied endemic communities: the profile peaks sharply at around the age of 10 years falling away rapidly to much lower levels in adults. This is in stark contrast to the patterns of water contact, which differ greatly between fishing and non-fishing communities. On Lake Albert, adults appear to be more heavily exposed than children. From these observations we conclude that adults are physiologically (perhaps immunologically) more resistant to infection after treatment than children.

Peri-portal fibrosis can be a serious sequelae of Schistosoma mansoni infection. Age or duration of exposure have been identified as important risk factors, but their relative importance cannot be easily separated. Here, we have compared two cohorts, aged 6-50 years and resident for ten years or since birth, from two neighbouring villages (Booma and Bugoigo) on the eastern shore of Lake Albert, Uganda. Parasitological measurements were similar, whereas the prevalence of peri-portal fibrosis was 5-fold higher in Booma. Data from the cohorts were pooled to assess the relative contribution of age and duration of residency on the risk of disease. Amongst adults, duration of residency was the critical risk factor--individuals aged 17-31 years resident for more 22 years had an almost 12-fold increased risk of fibrosis than those resident for less than 15 years. Height-standardised Splenic Vein Diameter (SVD), Portal Vein Diameter (PVD), Para-sternal Liver Length (PLL) and Spleen Length (SL) values were all higher in Booma, and each organometric parameter except PLL increased with the severity of fibrosis. Our results clearly demonstrate that duration of exposure is a critical risk factor for the development of peri-portal fibrosis and its sequelae in adults. This parameter should therefore be a routine measurement during epidemiological surveys of S. mansoni.

Abstract. 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 moderateto-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.Various measures are used to assess infection and pathology due to Schistosoma haematobium.1 Egg counts are the standard indirect morbidity parameter measuring infection. Hematuria detected by reagent strips is another indirect measurement of urinary tract lesions in S. haematobium infections. Currently, schistosomiasis control programs in endemic areas aim at reducing morbidity in the population, 2 so it is important to document the prevalence of pathologic lesions before and after interventions. Ultrasound scanning of the urinary tract provides visible evidence of pathology. It is a safe tool that can be used in the field and is reliable, especially in detecting significant pathology. 3 The dynamics of clearance of pathologic lesions within six months after effective treatment with praziquantel in areas of mild-to-moderate transmission have been documented by Hatz and others using ultrasound. 4 Little is known about the dynamics of pathology after clearance in areas with continuous re-exposure. Such information is clearly required to reach informed decisions on treatment and re-treatment schedules. Based on previous experience in the same area, 4 the present study was designed to assess the evolution of pathology after treatment, and the severity and the incidence of reappearance of lesions due to S. haematobium in an area of moderate-to-high transmission over a peri...

Schistosoma mansoni infection, associated morbidity and symptoms were studied in Piida fishing community at Butiaba, along Lake Albert, Uganda, from November 1996 to January 1997. The study revealed that S. mansoni is highly endemic with an overall prevalence of 72%, a mean intensity of 419.4 eggs per gram (epg) faeces (geometric mean for positives only), with 37.8% of males and 33.0% of females excreting over 1000 epg. Prevalence and intensity peaked in the 10-14 year old age group and decreased with increasing age. Females were less heavily infected than males. Differences were also shown between tribes. Diarrhoea and abdominal pain were commonly reported in Piida. However, no clear-cut correlation between intensity of S. mansoni infection and these conditions could be demonstrated, indicating that retrospective questionnaires concerning S. mansoni related-symptomatology are of limited value. Organomegaly, as assessed by ultrasonography, was frequent and hepatomegaly was associated with heavy S. mansoni infection. No correlation was demonstrated between splenomegaly and infection. This study emphasizes that schistosomiasis mansoni is a major public health problem in Piida fishing community and presumably also in many similar fishing communities. These observations call for immediate intervention and can help in planning long-term strategies for sustainable morbidity control.

Objectives:To assess the effect of zinc supplementation on growth and body composition among schoolchildren. Design: Randomized, double-blind, placebo-controlled trial. Setting and Subjects: 313 rural Zimbabwean schoolchildren (144 boys and 169 girls), 11-17 y). Interventions: Supplementation with zinc (30 or 50 mg) or placebo on schooldays for 12 months. Due to drought, a food programme was in operation during the last eight months of the study. Variables: Weight, height, upper arm circumference, triceps skinfold thickness, and weight-for-age, height-forage, weight-for-height, arm muscle-area-for-age and arm fat-area-for-age Z-scores. Results: Significant effects on weight gain (0.51 vs 0.14 kg, P 0.01), weight-for-age Z (70.08 vs 7 0.14, P 0.01) and arm muscle area-for-age Z-score (0.10 vs 0.01, P 0.03) were seen over the first three months, whereas no effects were seen over the full 12 months. Conclusions: Zinc deficiency impairing lean body mass and weight gain was documented. However, the effect of zinc seen over the first three months vanished during the last nine months when the food programme was in operation. Zinc deficiency may have persisted, but another nutrient may have become growth limiting during the last nine months.

SummaryTo assess the morbidity of S. haematobium infection in women of reproductive age (15-49 years) in the western part of Madagascar, the village of Betalatala with a prevalence of urinary schistosomiasis in women of 75.6% (95% confidence limit 69.3 to 81.9%) was compared with a neighbouring village with similar socio-economic characteristics and a prevalence of 5.0% (95% confidence limit 0 to 11.75%). The women were questioned in Malagasy about obstetrical history and urogynecological symptoms. They were examined gynaecologically, parasitologically and by ultrasonography. Important STDs were excluded by appropiate diagnostics. In Betalatala significantly more women reported a history of spontaneous abortion (P Ͻ 0.01), complaints of irregular menstruation (P Ͻ 0.001), pelvic pain (Ͻ0.05), vaginal discharge (P Ͻ 0.0001), dysuria (P Ͻ 0.05) and haematuria (P Ͻ 0.01) than in the control village. Biopsies were obtained from the cervix of 36 women with macroscopical lesions, and in 12 cases S. haematobium eggs were found by histological sectioning (33.3%). In the control village no eggs were detected in the histological sections of biopsies taken from 14 women. (P Ͻ 0.05). Infections with Candida albicans, Trichomonas vaginalis, Gardnerella vaginalis and Treponema pallidum were found in similar frequencies in both villages. In 9.8% of the women in Betalatala abnormalities of the upper reproductive tract were revealed by ultrasonography versus none in the women from the control village (P Ͻ 0.05). Echographic abnormalities of the urinary tract were present in 24% and 3% of the women in the study village and in the control village, respectively (P Ͻ 0.0001). These findings were accompanied by an elevated frequency of haematuria (55% versus 20%) and proteinuria (70.4% versus 25%) in the study population (P Ͻ 0.0001). Our study indicates that S. haematobium infection in women may not only cause symptoms in the urinary tract, but also frequently in the lower and upper reproductive tract.

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Abstract. Eosinophiluria, as quantified by measuring eosinophil cationic protein (ECP) in urinary extracts, microhematuria, egg excretion, and ultrasound-detectable bladder pathology were recorded in Schistosoma haematobium-infected Tanzanian school children at a baseline survey and during an 18-month post-treatment followup study. Significant correlations were seen between urinary ECP levels, intensity of infection, and bladder pathology. Treatment resulted in a marked reduction in prevalence and intensity of infection, in a delayed and less marked reduction in ECP levels, and in a resolution of pathology. The overall diagnostic efficiency of the ECP test (cut-off value for the ECP Ն5 ng/ml) in relation to infection was comparable with that of egg count and microhematuria, but with a better sensitivity than a single egg count. In relation to bladder pathology, the diagnostic performance of the ECP test (cut-off value for the ECP Ն25 ng/ml) exceeded that of a single egg count. In addition, the ECP was better in discriminating between different grades of bladder pathology. The present study points to the ECP as a useful marker of both S. haematobium infection and of associated bladder morbidity reflecting the inflammatory status of the bladder wall.