Morbidity due to Schistosoma mansoni among sugar-cane cutters in Zimbabwe.

Quantitative determination of Schistosoma mansoni infection was carried out on 1995 cane cutters of the Hippo Valley and Triangle Sugar Estates. A total of 315 cutters were chosen for the study on the basis of S. mansoni infection and lack of anti-schistosomal chemotherapy during the previous three years. Stool consistency and blood and mucus in stool were determined for all the infected cutters. Overt and occult blood in stool was detected in a significantly high number of infected people compared to the control subjects (chi 2 p less than 0.001). However, the blood loss was found to have no anaemia-producing effect as determined by haemoglobin and red blood cell counts. Watery stool was prevalent among people with egg output exceeding 500 eggs per gram of stool. Mucus in stool was found to be more prevalent among infected people compared to the control subjects but the difference was not significant (p greater than 0.05). Symmer's periportal fibrosis (PPF) of various degrees of severity was detected in 47% of the infected people and grade one liver fibrosis was found in 7.5% of the control subjects (p less than 0.0001). Some 54.5% of those infected complained of abdominal pains compared to 35% of uninfected controls (p less than 0.01). There was a significant difference in the rate of absenteeism from work due to abdominal pains and diarrhoea among the infected and uninfected cane cutters (p less than 0.02).

Ultrasonographic assessment of Schistosoma mansoni and S haematobium morbidity in Zimbabwean schoolchildren.

Ultrasound examinations for Schistosoma haematobium - and S. mansoni-related morbidity were done in 174 schoolchildren from a subsistence farming community in southern Zimbabwe. The examinations were done according to the standardized protocol elaborated by the Cairo Working Group (the Cairo classification) and the Managil classification. Forty-six percent of the children had grade I periportal thickening (PPT) on ultrasound according to the Cairo classification, but none had grade II or higher. The significance of grade I PPT in the Cairo classification is questionable, since there were no differences between those without and those with grade I PPT with respect to intensity of S. mansoni infection or liver size. The prevalence of grade I PPT according to the Managil classification was 10%, and no association between the two classifications was seen. In multiple regression analysis, S. mansoni egg output was found to be a significant predictor of liver size, when controlling for height and sex. An interaction between S. haematobium and S. mansoni infection is suggested because the positive relationship between S. mansoni and liver size was seen in the presence but not in the absence of S. haematobium infection.

Circulating anodic antigen (CAA) levels in different age groups in a Zimbabwean rural community endemic for Schistosoma haematobium determined using the magnetic beads antigen-capture enzyme-linked immunoassay.

A simplified version of the magnetic bead antigen-capture enzyme-linked immunoassay (MBAC-EIA) was used to detect circulating anodic antigen (CAA) in individuals of different age groups with Schistosoma haematobium infection only in an endemic area of Zimbabwe. An overall positive correlation between S. haematobium egg excretion and CAA levels was demonstrated. The age profile for CAA levels was generally comparable with the age profile of S. haematobium prevalence and intensity of infection. The CAA levels were higher in younger (5-14 years of age) individuals than in older (greater than 14 years of age) ones. Since the sensitivity of the MBAC-EIA in the diagnosis of S. haematobium infection was found to be 97%, CAA levels appear to be a useful indicator of worm burden in an endemic area.

Schistosomiasis infection in relation to the ABO blood groups among school children in Zimbabwe.

The study aimed to establish if there was any relationship between the blood group of the human host and schistosomiasis prevalence, intensity, incidence and related organ pathology. Urine and stool specimens were collected from the 735 school children attending a rural school in Zimbabwe to determine the Schistosoma haematobium and S. mansoni infection status of the children. The parasitology results were used to calculate prevalence and intensity of schistosomiasis infection. All the children, irrespective of infection status, were examined for signs of organ damage using ultrasonography before those that were infected were treated using a single dose of praziquantel. A blood specimen was taken from each child for blood group determination. Exactly 1 year later, parasitology was repeated to allow calculation of annual incidence of schistosomiasis infection. Of the children studied, 212 (28.8%) were of blood group 'A', 156 (21.2%) were of blood group 'B' while 367 (49.9%) belonged to blood group 'O'. The prevalence of S. haematobium was 59.6% (n = 438) while that of S. mansoni was 15.60% (n = 115). S. haematobium infection was detected among 129 (60.8%) children belonging to blood group 'A': 225 (61.30%) of blood group 'O' and 84 (53. 80%) of those belonging to blood group 'B'. S. mansoni infection was detected among 65 (30.70%) blood group 'A' children while 37 (10.10%) blood group 'O' and 13 (8.30%) blood group 'B' children were infected. Intensity, annual incidence of S. haematobium infection and related organ pathology was significantly higher among children of blood group 'A' and lowest among blood group 'O' children (P < 0.01, F-value = 6.13). Similarly, S. Mansoni intensity and incidence of infection and related liver lesions were highest among children of blood group 'A' (P < 0.005, F-value = 11.45).

The impact of zinc supplementation on Schistosoma mansoni reinfection rate and intensities: a randomized, controlled trial among rural Zimbabwean schoolchildren.

OBJECTIVES: To assess the effect of zinc supplementation on susceptibility to S. mansoni reinfections 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. OUTCOME MEASURES: S. mansoni and S. haematobium reinfection rates and intensities. RESULTS: There was no difference in reinfection rates between the zinc and placebo groups (25 vs 29%, P = 0.46). However, the median intensity of S. mansoni reinfection, although low in both groups, was significantly lower in the zinc than in the placebo group (7 vs 13 eggs per gram of faeces, P = 0.048). No difference in either S. haematobium reinfection rates or intensities were seen. CONCLUSIONS: Zinc supplementation reduced the intensity of S. mansoni reinfections. Although the intensities of reinfection were very low, the finding probably reflects a biological effect of zinc that could be of public health importance in settings with higher transmission.

The impact of zinc supplementation on growth and body composition: a randomized, controlled trial among rural Zimbabwean schoolchildren.

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-for-age, 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 (-0.08 vs -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.

Serum concentration of micronutrients in relation to schistosomiasis and indicators of infection: a cross-sectional study among rural Zimbabwean schoolchildren.

OBJECTIVE: To study the relation between indicators of infection and Schistosoma mansoni and S. haematobium infection, and serum concentrations of zinc, ferritin and retinol. DESIGN: Cross-sectional. SETTING AND SUBJECTS: 313 rural Zimbabwean schoolchildren (144 boys and 169 girls, 11-17 years). VARIABLES: S. mansoni and S. haematobium egg output, concentration of C-reactive protein, neutrophil count, questionnaire data on fever and diarrhoea, and serum concentrations of retinol, ferritin and zinc. RESULTS: Age, elevated CRP, fever and S. mansoni egg output were significant predictors of the concentration of retinol. The regression coefficient for age was positive, and negative for elevated CRP, fever and S. mansoni egg output. As S. mansoni, but not S. haematobium, was of significance, it is unlikely that low retinol level increased susceptibility to infection. The effect of S. mansoni on retinol level was 0.03 mumol/l (95% CI: 0.002-0.06, P = 0.03) for each 100 eggs/g increase in egg output. Neither indicators of infection nor age and sex were predictors of concentration of zinc and log10 concentration of ferritin. CONCLUSION: S. mansoni infection reduced retinol level, when indicators of infection and age were controlled for. High intensities of S. mansoni infection may induce vitamin A deficiency among children with marginal vitamin A status. The study emphasizes the importance of controlling for age and metabolic response to concurrent infections in studies using serum retinol as a measure of vitamin A status.

Traditional herbal remedies used for the treatment of urinary schistosomiasis in Zimbabwe.

A total of 286 traditional healers, 85% of them registered with the Zimbabwe National Traditional Healers' Association (ZINATHA), in five administrative provinces of Zimbabwe, were interviewed to assess their knowledge about the signs and symptoms of urinary schistosomiasis. Information on the names of plants used to treat Schistosoma haematobium infections was solicited. Haematuria was mentioned by 99% of the traditional healers to be the most obvious sign of S. haematobium infection. General body weakness, increased urinary frequency and pain on micturition also were reported to be some of the signs of infection. Eight plant materials were identified as the most commonly used for the treatment of S. haematobium. The plants were identified and parts collected to investigate their antischistosomal properties. The plant materials were prepared according to the guidelines of the traditional healers and their efficacy determined by administering the crude extracts orally to hamsters infected with S. haematobium cercariae. The results obtained suggested that plant extracts from Abrus precatorius (Leguminosae), Pterocarpus angolensis (Leguminosae) and Ozoroa insignis (Anacardiaceae) were lethal to adult schistosomes.

A cross-sectional study on the prevalence and intensity of schistosomiasis among sugar cane cutters in Zimbabwe.

A schistosomiasis prevalence and intensity survey was carried out among sugar cane cutters of Hippo Valley and Triangle, the two largest irrigated sugar estates in Zimbabwe. Urine and stool specimens were collected for determination of schistosomiasis infection from 1995 cane cutters. A total of 315 (15.8pc) cutters were found to be infected with Schistosoma mansoni while 163 (8.2pc) were found to be positive for S. haematobium. The arithmetic mean egg count (AMEC) and geometric mean egg count (GMEC) for the different age groups into which the cane cutters were divided was calculated. The prevalence and intensity of S. mansoni increased with age while the opposite was true for S. haematobium. The factors contributing to this observation are discussed.

A cost effective two step rapid diagnosis of urinary schistosomiasis in Zimbabwe.

OBJECTIVE: To assess the efficacy and applicability of questionnaires to determine schistosomiasis endemic areas in Zimbabwe. DESIGN: Cross sectional study. SETTING: Makonde District, Zimbabwe. SUBJECTS: Headmasters and children in Grades II to V of the 121 schools in the district. MAIN OUTCOME MEASURES: Number of completed questionnaires that were returned. Ranking of the most important diseases among the school children. RESULTS: Completed questionnaires were received from 110 (90.9%) schools. Of the 110 headmasters, 55.4% ranked schistosomiasis < or = 4 as one of the priority diseases affecting their children most. In addition, 44.2% gave blood in urine < or = 4 as one of the most frequent symptoms among their school children while 63.6% wanted action to be taken to prevent schistosomiasis and/or blood in urine among the children. A total of 38.3% of the children from 37 schools admitted having suffered from schistosomiasis during the last month while 37.4% of the children from 35 schools claimed to have experienced blood in their urine during the same period of time. The teachers found a prevalence of 46.1% while the research team found that 44.9% children had blood in their urine. CONCLUSION: The results of this study demonstrated that the questionnaire approach, besides the high diagnostic power, was the cheapest, costing only US$0.08 per child and 18 times cheaper than the filtration technique.

The physical fitness and work performance of agricultural workers infected with Schistosoma mansoni in Zimbabwe.

Stool specimens were collected from 1995 sugarcane cutters on the Hippo Valley and Triangle sugar estates, Zimbabwe, in order to determine the prevalence and intensity of Schistosoma mansoni infection. Pathological changes normally ascribed to S. mansoni infection were assessed in the infected cutters, by ultrasonography before treatment. The height, weight, age, haemoglobin levels, blood pressure and body fat of the infected and uninfected control study subjects, standardized by age, were determined. Those with elevated blood pressure were excluded from the study. Physical fitness and work performances were assessed in 287 infected and 210 uninfected cane cutters aged (mean +/- S.D.) 36.5 +/- 7.5 years. Despite the finding that all the subjects were of good nutritional status and generally physically fit, a t-test showed a significant improvement (P < 0.01) in the performance of the infected cutters following treatment; age-related physical performance, measured by the Harvard Step Test, increased by 4.3% and work output, measured as the amount of cane cut in a given time, rose by 16.6%. Although the physical and work performances of the uninfected control subjects also increased over the same period, this trend, attributed to occupational physical exercise, was not statistically significant (P > 0.05). Significant correlations were found between both infection intensity-related pre-treatment physical fitness (P < 0.05) and work performance (P < 0.01) and prevalence of Symmers' peri-portal fibrosis.

Ultrasonographic organometry: liver and spleen dimensions among children in Zimbabwe.

Attempts have been made to develop a staging system of sonographic Schistosoma mansoni morbidity for use in epidemiological studies and for evaluation of control programmes. Therefore, normal dimensions of livers and spleens in children in countries with endemic S. mansoni infections need to be established. Normal dimensions of livers and spleens are presented, based on examination of 144 Zimbabwean children between 8 and 16 years of age found to be S. mansoni egg negative 12 months after treatment with praziquantel. Based on the liver and spleen measurements, an index of liver size and the spleen volume were calculated. Height was employed as the independent variable in all multiple regression models. The organometric data are presented as prediction plots, with observed values and fitted regression line with 95% confidence and prediction intervals. The mean spleen volume was 30% larger for boys than for girls, whereas there was no consistent difference in liver size. No effect of growth Z-scores was seen. The measurements were compared with normal dimensions of livers of German children. For a given height, the mean index of liver size was lower in Zimbabwean than in German children, but inter-observer variation could be a possible explanation for this difference.