Relationship between bladder cancer incidence, Schistosoma haematobium infection, and geographical region in Zimbabwe

Bladder cancer is common in Zimbabwe, possibly due to the high prevalence of Schistosoma haematobium infection in some areas. We undertook a correlational study based on retrospective medical record review to see whether the number of bladder cancers could be related to geographical region and prevalence of S. haematobium infection. We also determined patient demographic characteristics and tumour histology. Of 483 patients identified (1984-1987), 69% with available histology had squamous cell carcinomas. The remainder had transitional cell carcinomas. Patients with squamous cell carcinoma were younger than patients with transitional cell carcinomas (50% vs 20% under 50 years old, P less than 0.05) and had a sex ratio of one. There was a positive geographical relationship between S. haematobium prevalence and the incidence of squamous cell carcinoma of the bladder: provinces with high prevalence of S. haematobium had more bladder cancer cases with a predominance of squamous cell carcinoma (r = 0.87, P less than 0.01). These data support a casual relationship between S. haematobium infection and squamous cell carcinoma of the bladder.     

Water demand and schistosomiasis among the Gumau people of Bauchi State, Nigeria

A helminthological study of stool and urine samples from 1037 people from 4 rural communities in Gumau District of Bauchi State, Nigeria, was carried out using formol-ether concentration and direct centrifugation methods respectively. 39.0% of persons examined were infected. Ova of Ascaris lumbricoides, Schistosoma haematobium and S. mansoni were the most common. Trichuris trichiura, hookworm, tapeworm and Strongyloides stercoralis were also encountered. 17.9% and 10.8% of examined persons had S. haematobium and S. mansoni infections respectively. A significant relationship was found between water demand index (number of persons per well) and infection with S. haematobium (r = 0.95) and S. mansoni (r = 0.88) (P less than 0.01). Such a relationship was not found with other helminth infections. A significant association was also found between distance from a river and prevalence of S. haematobium (r = 0.94) and S. mansoni (r = 0.95) (P less than 0.01), but not with the other helminth infections. These findings suggest that the water demand index may be an important factor in the epidemiology of schistosome infections in rural communities.     

The burden of polyparasitism among primary schoolchildren in rural and farming areas in Zimbabwe

A cross-sectional study was conducted in Zimbabwe among 1303 primary schoolchildren from a rural (53.3%) and a commercial farming area (46.7%) to determine the prevalence of co-infection by helminths and Plasmodium falciparum. Urine was examined on three successive days using the filtration method. Two stool specimens were processed using the Kato-Katz method and a third specimen was processed using the sedimentation method. Plasmodium falciparum was diagnosed from thick blood films. The prevalence of Schistosoma haematobium in the rural and farming areas was 66.8% and 52.3%, respectively, and for S. mansoni the prevalence was 12.4% and 22.7%, respectively. Plasmodium falciparum, hookworms, Ascaris lumbricoides and Trichuris trichiura occurred only in the farming area, with a prevalence of 27.9%, 23.7%, 2.1%, 2.3%, respectively. Co-infection and triple infection with schistosomes, P. falciparum and soil-transmitted helminths occurred in the commercial farming area only. Hookworm and S. mansoni infections were associated with P. falciparum malaria (P<0.001, OR=2.48, 95% CI 1.56-3.93 and P=0.005, OR=1.85, 95% CI 1.20-2.87, respectively). Overlap of helminths with malaria is a concern among primary schoolchildren and incorporating helminth control in programmes aiming to control malaria will improve funding and increase the efficiency of control for neglected tropical diseases in identified co-endemic settings.     

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).     

A prospective study: prediction of the first variceal haemorrhage in schistosomal and non schistosomal liver disease

A prospective study was conducted on liver disease patients without previous history of bleeding (haematemesis and/or melena) to identify those at highest risk of bleeding. A hundred and twenty non-alcoholic patients (96 males and 24 females), ages ranging from 30 to 60 years were studied. Patients were followed for up to two years or to time of bleeding (mean 18 +/- 7.3 months), during which 34 (28.3%) patients bled. Schistosomal patients showed less incidence of bleeding (12.1%, p < 0.05) than those with mixed aetiology (Schistosoma and cirrhosis 23.5%, and chronic active hepatitis and schistosoma 44.4%). The presence of positive viral markers (either HCV antibodies or HBsAg) was associated with a higher percent of bleeding during the follow-up period (43.2% and 45.4%, respectively), than those negative for these markers (21.7%, 24.4%, respectively). Univariate analysis showed the following significant risk factors associated with bleeding: modified child classification, reduced platelet count, endoscopic findings of cherry red spots, gastric varices and increased grade of oesophageal varices. Multivariate analysis revealed that the risk of bleeding was significantly related to the presence of cherry red spots, the presence of gastric varices, grade of oesophageal varices and the patient's prothrombin time. In conclusion, bleeding from oesophageal varices is a frequent and serious event in patients with chronic liver disease. The risk of variceal bleeding from liver disease with mixed aetiology (schistosomiasis associated with viral hepatitis HBV or HCV) was found to be significantly higher than that with schistosomal aetiology alone. The endoscopic findings of cherry red spots, gastric varices, increased grade of oesophageal varices and to a lesser extent the prothrombin time were found to be high risk factors. Patients having those risk factors should be considered for prophylactic measures.     

How much time do patients with diabetes spend on self-care?

INTRODUCTION: Little is reported about how much time patients spend on self-management, a cornerstone of diabetes care. METHODS: We studied a cross-section of 1482 diabetic patients enrolled in 3 northeastern United States managed care plans. Patients were surveyed about how much time they spent on foot care, exercise, and food shopping/preparation (7/00 to 9/01). Logistic regressions modeled which types of patients were likely to spend time, and linear regressions modeled characteristics associated with spending more/less time. RESULTS: Patients (57.9% > or = 55 years; 51.6% women; 36.2% African American; 31.1% on insulin) spent 58 (mean) minutes/day on self-care (interquartile range 19, 84). Many patients skipped individual self-care elements: 37.9% reported no foot care, 37.7% no exercise, and 54.4% no time on food shopping/preparation. One fourth of patients with severe foot neuropathy symptoms spent no time on foot care. Never self-testers were less likely than others to engage in foot care (odds ratio (OR) 0.4 (95% CI 0.3, 0.6), exercise (OR 0.4 (95% CI 0.3, 0.6)), and food shopping/preparation (OR 0.7 (95% CI 0.5, 1.0)), and were likely to spend 30 minutes less total self-care time than frequent self-testers (P <.01). DISCUSSION: Most people spent considerable time engaged in self-care, but many skipped individual tasks, offering clinicians opportunities for collaborative decision making.     

Schistosoma mansoni morbidity among adults in two villages along Lake Victoria shores in Mwanza District, Tanzania

The study aimed to describe morbidity patterns due to intestinal schistosomiasis in adults living in two villages along the southern shores of Lake Victoria, Mwanza District, Tanzania. Nine hundred and fifty persons from Msozi and 497 from Sangabuye, aged between 14 and 87 years, were examined by abdominal ultrasound according to the Niamey protocol. Liver image patterns (LIP) A and B were considered normal and C-F as distinct periportal fibrosis (PPF). The frequency of PPF was higher in Msozi (41.5%) than in Sangabuye (16.7%) (P<0.001) and was associated with high prevalence and intensity of Schistosoma mansoni infection. PPF was shown to be more common in males than females. Abnormal increase of segmental branch wall thickness (SBWT) and dilated portal vein diameter (PVD) were also more common among males than females. Hepatomegaly and splenomegaly were frequently encountered in both villages. The LIPs were positively correlated to size of SBWT and PVD but not to size of left liver lobe or spleen. In the study communities the risk of developing PPF differed greatly among individuals depending on various risk factors especially alcohol consumption.     

Health risk behavior of rural secondary school students in Zimbabwe.

A socioculturally appropriate health risk behavior instrument, modeled after the U.S. Centers for Disease Control and Prevention's Youth Risk Behavior Survey (YRBS), was administered to 717 secondary school students in a rural area of Zimbabwe. Comparisons of risk behaviors by gender and school grade were made using univariate procedures and multiple logistic regression. Males were significantly more likely than females to have had sexual intercourse (odds ratio = 5.02, p < .0001) and to report drug use behaviors. Males also were significantly more likely to report early initiation (by age 13 years) of alcohol use, cigarette smoking, and marijuana use. School site violence and drug use behaviors also were prevalent in this sample. An interaction between gender and grade was evident for some behaviors. Additional research may further the understanding of these risk behaviors and facilitate development of effective, culturally relevant risk reduction programs.     

Rapid screening for Schistosoma mansoni in western Côte d'Ivoire using a simple school questionnaire

The distribution of schistosomiasis is focal, so if the resources available for control are to be used most effectively, they need to be directed towards the individuals and/or communities at highest risk of morbidity from schistosomiasis. Rapid and inexpensive ways of doing this are needed, such as simple school questionnaires. The present study used such questionnaires in an area of western Côte d''Ivoire where Schistosoma mansoni is endemic; correctly completed questionnaires were returned from 121 out of 134 schools (90.3%), with 12,227 children interviewed individually. The presence of S. mansoni was verified by microscopic examination in 60 randomly selected schools, where 5047 schoolchildren provided two consecutive stool samples for Kato-Katz thick smears. For all samples it was found that 54.4% of individuals were infected with S. mansoni. Moreover, individuals infected with S. mansoni reported "bloody diarrhoea", "blood in stools" and "schistosomiasis" significantly more often than uninfected children. At the school level, Spearman rank correlation analysis showed that the prevalence of S. mansoni significantly correlated with the prevalence of reported bloody diarrhoea (P = 0.002), reported blood in stools (P = 0.014) and reported schistosomiasis (P = 0.011). Reported bloody diarrhoea and reported blood in stools had the best diagnostic performance (sensitivity: 88.2%, specificity: 57.7%, positive predictive value: 73.2%, negative predictive value: 78.9%). The study, which is probably the largest of its kind ever undertaken in Africa, revealed a moderate diagnostic performance of questionnaires for identifying individuals and/or communities at high risk from S. mansoni.     

Epidemiology of schistosomiasis mansoni in a low endemic area

We discuss the epidemiological patterns of schistosomiasis mansoni in areas with low transmission in Brazil. We define as areas of low endemicity those where the prevalence is less than 10%, the number Schistosoma mansoni eggs per gram of feces (epg) is less than 96, and carriers are asymptomatic. Data are from the county of Pedro de Toledo in the Ribeira Valley (S?o Paulo State) and were collected randomly according to the aggregate pattern of S. mansoni within the hosts. We suggest the replacement of parasitological methods by more sensitive and specific serological techniques. The main risk factor for infection is type of leisure activity. Infection is more frequent in the 10-14, 15-19, and 20-24-year age brackets. Geometric mean epg is 58.5. Intensity of infections correlates well (rs = 0.745) with prevalence. The highest index of potential contamination is in the 5-20-year age bracket (57.6%). Autochthonous cases show close association with Biomphalaria tenagophila, which has a low infection rate (2%). Prevalence, incidence, and intensity of infection patterns are similar to those of moderate and high endemic areas. Social and cultural aspects must be studied in order to obtain a global epidemiological view of schistosomiasis.     

An epidemiological study of foci of S. mansoni bilharziosis in Minkana and Nalassi (Lekie Division, Cameroun) (author's transl)]

The epidemiological survey involved the examination of the total population of the two villages as well as the investigation of the freshwater snails in the neigbouring waters bodies. Biomphalaria camerunensis and Biomphalaria pfeifferi were found to be the intermediate hosts of Schistosoma mansoni. The cassage of eggs in the stools was more frequently observed in two groups, those aged 10-19 years and in the elderly women. The study of the prevalence of the disease by means of the indirect immunofluorescence technique on frozen sections of S. mansoni revealed that already in childhood the percentage of subjects with circulating antibodies is high. This percentage remains elevated in subsequent age groups. The geometrical mean reciprocal titers show an age and sex pattern similar to that found for prevalence. Both the percentage of positive indirect immunofluorescence tests and their respective titers were higher in patients with eggs in their stools. The immunological reaction using homologous S. mansoni antigen is more sensitive than that with heterologous S. haematobium antigen.     

Influence of vitamin A on the immune response of Schistosoma mansoni-infected rats

Nutritional (vitamin A levels, weights), parasitological (adult worm burden, count of eggs in liver, stool examination) and immunological (IgE serum levels, anti-Schistosoma mansoni antibodies, lymphocyte stimulation by concanavalin A and S. mansoni antigenic extract) parameters were studied in three groups of rats, a non-infected and normally fed control group, a S. mansoni-infected but normally fed group, and a S. mansoni-infected group with experimentally induced vitamin A deficiency. The number of worms was found significantly higher in the third (53 +/- 19) than in the second group (2 +/- 2) (p less than 0.001). There were many eggs in the liver surrounded by granulomatous reactions in the third group (399 +/- 73 epg liver). All stool examinations were negative. IgE levels and anti-S. mansoni antibody titres were significantly lower (p less than 0.001) in the third than in the second group. The concanavalin A lymphocyte stimulation indexes did not differ significantly between groups 2 and 3; the S. mansoni lymphocyte stimulation index was only significantly positive in group 3 (p less than 0.001). These results indicate a decrease in the humoral immune response without alteration of cellular immune response in vitamin A-deficient rats infected with S. mansoni.     

Socioeconomic predictors of high allergen levels in homes in the greater Boston area

In the United States, childhood asthma morbidity and prevalence rates are the highest in less affluent urban minority communities. More than 80% of childhood asthmatics are allergic to one or more inhalant allergens. We evaluated whether socioeconomic status was associated with a differential in the levels and types of indoor home allergens. Dust samples for an ELISA allergen assay were collected from the homes of 499 families as part of a metropolitan Boston, Massachusetts, longitudinal birth cohort study of home allergens and asthma in children with a parental history of asthma or allergy. The proportion of homes with maximum home allergen levels in the highest category was 42% for dust mite allergen (> or = 10 microg/g Der p 1 or Der f 1), 13% for cockroach allergen (> or = 2 U/g Bla g 1 or Bla g 2), 26% for cat allergen (> or = 8 microg/g Fel d 1), and 20% for dog allergen (> or = 10 microg/g Can f 1). Homes in the high-poverty area (> 20% of the population below the poverty level) were more likely to have high cockroach allergen levels than homes in the low-poverty area [51 vs. 3%; OR, 33; 95% confidence interval (CI), 12-90], but less likely to have high levels of dust mite allergen (16 vs. 53%; OR, 0.2; CI, 0.1-0.4). Lower family income, less maternal education, and race/ethnicity (black or Hispanic vs. white) were also associated with a lower risk of high dust mite levels and a greater risk of high cockroach allergen levels. Within a single U.S. metropolitan area we found marked between-community differences in the types of allergens present in the home, but not necessarily in the overall burden of allergen exposure.     

Control of schistosomiasis transmission in newly established smallholder irrigation schemes

The extent to which schistosomiasis can be controlled through careful design of the irrigation works, the operation schedule, the location of villages and the provision of safe water supplies and sanitation in smallholder irrigation schemes at Mushandike in south-east Zimbabwe is reported. The schemes provide land for 400 peasant families who are monitored for schistosomiasis soon after resettlement. Between April 1986 and August 1987 there was a marked reduction in overall prevalence following treatment. For Schistosoma haematobium, the reductions in 2 schemes were 53% and 82% and for S. mansoni, 82% and 100%, in spite of transmission in settlements upstream from the schemes. In contrast, in a nearby irrigated farm where no control measures were introduced, S. haematobium prevalence declined by only 31% while that for S. mansoni increased by 22% a year following treatment. These results are supported and strengthened by measurements of snail population sizes and their infection rates, cercarial densities in the water and incidence data for the human population, and suggest that the engineering and environmental control measures introduced are significant means of controlling transmission in smallholder irrigation schemes with the lowest recurrent costs.     

中山市儿童期超重对青少年肥胖影响的队列研究

目的 了解广东省中山市7~18岁儿童青少年肥胖的发病率,探讨儿童期超重对青少年肥胖的影响。方法 于2005年对中山市一年级小学生体检测量身高、体重,连续随访10年(1次/年),共有2 188名中山市小学一年级到高中一年级学生作为回顾性队列研究对象。使用2018年颁布的《学龄儿童青少年超重与肥胖筛查》 (WS/T 586-2018) 评价超重及肥胖,并计算肥胖的检出率及发病率,采用χ²检验和log-binomial模型分析儿童期超重对青少年肥胖的影响。结果 小学一年级学生肥胖的检出率为4.89%,小学四年级时达到最高为6.99%,高中一年级时为4.43%。肥胖的发病率在小学二年级时最高为1.83%,高中一年级时降低到0.74%。小学一年级时超重的学生在高中一年级时肥胖累积发病率是小学一年级时正常体重学生的8.85倍(9年的累积发病率41.33% vs.4.67%,RR=8.85,95%CI:6.12~12.78)。结论 从小学一年级到高中一年级期间,儿童期肥胖发病率较高。儿童期超重明显增加青少年肥胖的风险。肥胖干预应该从儿童期开展,尤其应该重点关注超重的儿童。     

Epidemiology and morbidity of Schistosoma mansoni infection in a fishing community along Lake Albert in Uganda

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.     

Coworker violence and gender. Findings from the National Violence Against Women Survey

BACKGROUND: To further the understanding of coworker violence, we analyzed data from the National Violence Against Women (NVAW) Survey on the prevalence and characteristics of coworker violence among women and men, and compared the prevalence of coworker violence with violence perpetrated by other types of perpetrators. METHODS: The NVAW Survey was conducted during November 1995-May 1996 and consists of telephone interviews with a representative sample of 8000 U.S. women and 8000 U.S. men aged > or = 18 years about their experiences as victims of violence by all types of perpetrators, including coworkers. RESULTS: Lifetime coworker victimization rates varied significantly between women and men (1.1% and 2.3%, respectively), while annual victimization rates were the same (0.1%). Both women and men were more likely to be victimized by a stranger, intimate partner, or other type of acquaintance/family member than a coworker. Women victims of coworker violence were significantly more likely than their men counterparts to be raped or stalked, and significantly less likely to be physically assaulted. No significant differences were found between female and male coworker violence victims with respect to race, age, education, or rate of injury; however, female victims were significantly more likely to lose time from work as a result of their victimization and to report their victimization to the police. CONCLUSION: An estimated 1.1 million U.S. women and 2.3 million U.S. men have ever been victimized by a current or former coworker, while 100,697 U.S. women and 92,748 U.S. men are victimized by a current or former coworker annually.     

Patterns of concurrent hookworm infection and schistosomiasis in schoolchildren in Tanzania

A cross-sectional study of 6897 schoolchildren in 59 out of the 155 primary schools in Magu District on the shores of Lake Victoria, Tanzania, was undertaken in 1997 to determine the prevalence of single- and multiple-species helminth infection. Schistosoma haematobium, hookworm (primarily Necator americanus) and S. mansoni were the most common helminth species infecting schoolchildren in the district. The prevalences of Ascaris lumbricoides and Trichuris trichiura were negligible (< 1%). Anaemia and stunting were highly prevalent and widespread. Hookworm and S. mansoni occurred more frequently in multiple infections with other helminths than as single-species infections, but triple-species infection was rare. Analysis of the frequency distribution of infection amongst schools showed that prevalences of S. haematobium and hookworm tended to be normally distributed, with medians 75% and 45%, respectively, while the distribution of S. mansoni was markedly skewed such that only 17% schools had a prevalence greater than 20%. An inverse association between S. mansoni and S. haematobium was observed. Geographical information system (GIS) analysis indicated that S. mansoni infection was highly prevalent only along the shore of Lake Victoria, whilst S. haematobium was homogeneously prevalent everywhere except the lakeshore. This pattern appears to reflect the distribution of schistosome species-specific snail intermediate hosts. The results imply that joint treatment for hookworm infection and schistosomiasis would be beneficial throughout the district.     

Disparities in pediatric obesity in the United States

This paper describes the disparities in the U.S. childhood obesity epidemic, mainly based on recent nationally representative data. The prevalence of overweight and obesity has increased since the late 1970s; the over time shifts (changes) in distributions of various body fatness measures indicate that U.S. children have become fatter and the obese groups gained more body fat, especially more central obesity, as indicated by waist circumference. However, considerable between-group and regional disparities exist in the prevalence, fatness measures, and over time trends. The disparities and trends are complex, which reflects the complexity and dynamics in obesity etiology. Clearly, some population groups are affected more seriously than others. Native American children have the highest prevalence of obesity, whereas Asians have the lowest rate among all ethnic groups. Preschool age children have a lower obesity prevalence than older children. Young people in some states and cities are twice more likely to be overweight or obese than those living in other regions. Low-socioeconomic status is associated with obesity only among some population groups, e.g. white children and adolescents. Vigorous, effective interventions are needed to promote healthy lifestyles among U.S. young people and to reduce disparities in obesity.     

Prevalence of schistosoma mansoni and intestinal parasites with evaluation of hepatic schistosomiasis in a rural area after governmental efforts (Gharbia governorate)

The study was carried out on 2136 individuals from Abo El-Gohoor village. Their ages ranged from 1-72 years with a mean of 28.3 +/- 22.4 years. They were 46.7% males and 53.3% females. The village was divided into sectors. The inhabitants of each sector were examined clinically with history taking through home visits. Three successive stool samples for each individual were examined by the concentration technique. Abdominal ultrasound was done for hepatic and splenic assessment. Rectal biopsy was done for 200 subjects with negative stool samples for Schistosoma mansoni (S. mansoni) ova. Sex distribution was equal in this group. Their ages ranged from 18 to 45 years with a mean of 30.1 +/- 9.5 years. S. mansoni prevalence was 19.3% of individuals through stool examination and 12.5% out of 200 individuals with active schistosomiasis after rectal biopsy (the total prevalence was approximately 29.4%). Hepatic schistosomiasis was 18.8%. Hepatomegaly, hepatosplenomegaly, hepatic fibrosis without and with ascites were 6.0%, 8.8%, 2.5% and 1.5% of examined patients, respectively. The prevalence of intestinal parasites was 37.5% and 27.8% for E. histolytica and G. lamblia, respectively, 9.2% for H. nana, 6.2%, 9.6%, 2.4% and 1.5% for A. lumbricoides, E. vermicularis, T. trichura and A. duodenale, respectively and F. gigantica was 0.4%. A total of 84.6% of examined subjects had parasitic infestations, 60.2% had one parasite, 19.6% had 2 parasites, 4.2% had 3 parasites and 0.7% had 4 parasites. The study revealed some success of governmental efforts for control of schistosomiasis. The prevalence of S. mansoni through stool examination showed a prevalence lower than that reported before but which does not represent the actual prevalence of S. mansoni and rectal biopsy in addition gave more accurate results.