The effect of Schistosoma mansoni infection of the productivity of cane cutters on a sugar estate in Tanzania

In an attempt to justify future snail control on an irrigated sugar estate in Tanzania, the effects of Schistosoma mansoni infection on the productivity of apparently healthy cane cutters were investigated. The bonus earnings of cane cutters who were found to be infected with S. mansoni were compared, retrospectively, with earnings of uninfected cane cutters during the years 1968-69. For one 6-month period a more detailed study was made to correlate bonus earnings with actual output in tons of cane cut. It was found that in the four 6-month periods the mean bonus earnings of the uninfected cane cutters exceeded the mean bonus earnings of the infected men by 11.0%, 11.4%, 6.0%, and 13.7%, respectively. In all except the third period these differences were statistically significant. After treatment for S. mansoni infection, the workers were able to improve their earnings relative to both infected and uninfected workers. In a more detailed study of some of the workers during the third 6-month period, it was discovered that a 4% difference in bonus earnings represented a 1% difference in output. Taking into account the variations of bonus earnings it was estimated that the overall difference in productivity between infected and uninfected workers was 3-5%.     

Sonographic studies of schoolchildren in a village endemic for Schistosoma mansoni

Parasitological, clinical, and sonographic examinations were performed on 309 school children in a village endemic for schistosomiasis mansoni. Data from the 255 denying treatment within the previous 2 years were analysed separately. On a single Kato examination 42% were uninfected; the remainder had light (26%), moderate (21%), or heavy (11%) infections with Schistosoma mansoni. Hepatomegaly (53%) and palpable spleens (35%) were common but clinical and parasitological findings often were unrelated. Abdominal sonography also demonstrated a high frequency of hepatomegaly (82%) and splenomegaly (49%). Sonographically determined liver span and spleen size correlated with the egg count. Sonographic lesions of periportal fibrosis of schistosomiasis mansoni with thickening of portal tracts and portal vein walls were frequently present and more common in infected than in uninfected children, and were correlated with the number of S. mansoni ova in the stool. Ultrasonographically detected periportal fibrosis was a reliable measurement of the prevalence and morbidity of schistosomiasis mansoni in this population, and provided very useful information, even when the parasitological and clinical findings were equivocal.     

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.     

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.     

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.     

家庭中轮状病毒感染的研究

用聚丙烯酰胺凝胶电泳法对72个家庭中的194人的粪便标本进行了轮状病毒检测。48份婴幼儿腹泻粪便中有29份轮状病毒阳性,24份健康儿童粪便中仅有一份阳性。80个与轮状病毒感染患儿密切接触的成人中,17个受轮状病毒感染,而未与轮状病毒感染患儿接触的44个成人中仅2人受感染(P<0.05)。成人感染轮状病毒后多无明显临床症状,少数表现为轻微腹泻和腹痛,但他们很可能是轮状病毒感染的重要传染源。     

Assessment of the age-specific disability weight of chronic schistosomiasis japonica

OBJECTIVE: To estimate the age-specific disability weight of chronic schistosomiasis japonica in China. METHODS: Between October 2004 and January 2005, residents from two schistosome-endemic counties were screened for Schistosoma japonicum infection using an enzyme-linked immunosorbent assay. Disability and morbidity were assessed in seropositive individuals using the European quality of life questionnaire with an additional cognitive dimension (known as the "EQ-5D plus") and ultrasonography. The age-specific disability weight of chronic schistosomiasis was estimated based on participants self-rated health scores on the visual analogue scale of the questionnaire; the relationships between health status, morbidity and disability weight were explored using multilevel regression models. FINDINGS: Of 2843 seropositive individuals, 1419 (49.9%) were classified as having chronic schistosomiasis. Hepatomegaly was found in 76.3% (1082/1419); hepatic fibrosis was found in 73.3% (1040/1419); and splenomegaly was found in 18.6% (264/1419). Diarrhoea was the most common self-reported symptom (46.0%; 653/1419), followed by abdominal pain (32.6%; 463/1419), impaired capacity to work or study (30.7%; 436/1419), and blood in the stool (11.1%; 157/1419). More than half of the respondents reported impairments in at least one dimension of the EQ-5D plus questionnaire, particularly pain or discomfort (47.9%; 675/1410) and anxiety or depression (39.4%; 555/1410). The overall disability weight was 0.191, and age-specific weights ranged from 0.095 among those aged 5-14 years to 0.246 among those aged > 60 years. Multilevel regression models indicated that the disability weight was significantly associated with the participants sex, grade of hepatic fibrosis, the presence of hepatomegaly, abdominal pain, blood in the stool, impaired capacity to work or study, and cognition. CONCLUSION: The disability weight attributable to chronic schistosomiasis japonica is high and increases with age. Our findings call for a reappraisal of the disability weights due to chronic schistosomiasis mansoni and schistosomiasis haematobia as well as a re-estimation of the global burden of schistosomiasis.     

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.     

Schistosoma mansoni infection in a new settlement in Metekel district, north-western Ethiopia: morbidity and side effects of treatment with praziquantel in relation to intensity of infection

A study of morbidity and side effects of treatment with praziquantel in relation to intensity of infection with Schistosoma mansoni was conducted in 406 infected individuals from a newly-settled village in Metekel, north-western Ethiopia. Each subject was submitted to a standardized medical history and abdominal palpation. The frequencies of hepatomegaly and splenomegaly were low, 2% and 3%, respectively. A positive association was found between egg load and a history of blood in the stool. Interviews on side effects were conducted on the day following treatment with praziquantel (40 mg/kg body weight). Positive correlations with egg load were found for several side effects, including abdominal pain, diarrhoea, headache, back pain, and vomiting. Unusual side effects involving swelling of various parts of the body confirm 2 previous reports from a different region in Ethiopia and should be investigated further.     

Prevalence, intensity and associated morbidity of Schistosoma japonicum infection in the Dongting Lake region, China

OBJECTIVE: To determine the prevalence and intensity of Schistosoma japonicum infection and associated morbidity, and to estimate the infected human and buffalo populations in the Dongting Lake region, Hunan province, China. METHODS: We used data from the third national schistosomiasis periodic epidemiological survey (PES) of 2004. These included 47 144 human serological and 7205 stool examinations, 3893 clinical examinations and questionnaire surveys, and 874 buffalo stool examinations, carried out in 47 villages in Hunan province. Serological examinations were performed using the enzyme linked immunosorbent assay technique and human stool samples were examined by the Kato-Katz method. Stools from buffaloes and other domestic animals were examined for schistosome infection by the miracidial hatching test. FINDINGS: Sero-prevalence was 11.9% (range: 1.3-34.9% at the village level), and the rate of egg-positive stools was estimated at 1.9% (0-10.9%) for the same population. The prevalence of infection among buffaloes was 9.5% (0-66.7%). Extrapolating to the entire population of the Dongting Lake region, an estimated 73 225 people and 13 973 buffaloes were infected. Most frequently reported symptoms were abdominal pain (6.2%) and bloody stools (2.7%). More than half of the clinically examined people reported having had at least one prior antischistosomal treatment. CONCLUSION: There was a significant reduction in the number of humans infected with S. japonicum since the previous national PES carried out in 1995, partially explained by large-scale chemotherapy campaigns. However, a near-stable number of buffalo infections suggest continuing human re-infection, which may lead to future increases in human prevalence.     

Efficiency and daily work effort in sugar cane cutters.

Productivity (metric tons (tonnes)/day), efficiency (kg cane cut/litre Vo2), and effort (percent Vo2 max sustained during an 8-hour workday) have been measured in 54 Colombian sugar cane cutters. In workers who sustained less than 40% Vo2 max during the workday, the effort expended was related to productivity (4 = 0-71) but efficiency and productivity were not significantly correlated. In 16 workers sustaining a greater than 40% Vo2 max during the workday, productivity and effort were not related and efficiency was significantly reduced. Subjects using less than 40% Vo2 max were divided into good, average and poor producers and compared with the men with low efficiencies. In general, these inefficient men had the anthropometric and physical fitness characteristics of low productivity workers (smaller stature, weight and Vo2 max). However, the frequency of good, average, and poor cutters in the inefficient group did not differ from that of the men expending less than 40% of their maximum effort nor was their average productivity different. No obvious reasons for the differences in efficiency and effort of these men were found.     

Genotyping of Pseudomonas aeruginosa sputum and stool isolates from cystic fibrosis patients: evidence for intestinal colonization and spreading into toilets

Three hundred and fifty-eight stool and 131 sputum specimens from 40 cystic fibrosis (CF) patients and 100 toilet sinks were investigated for occurrence of Pseudomonas aeruginosa; 67% (21/31) of the patients with chronic P. aeruginosa lung infections carried the organism repeatedly in the stool but the organism was found only once in the stools of nine uninfected patients. P. aeruginosa stool carriage was correlated to high P. aeruginosa numbers in patients' sputa. Typing of P. aeruginosa with a DNA probe showed identity of sputum and stool strains. Seven patients repeatedly carried additional stool strains, not found in the sputum, suggesting intestinal colonization. No differences were seen in the clinical state of patients with P. aeruginosa-negative stool samples and patients with positive stool samples. Toilets in households of P. aeruginosa-infected CF patients were significantly more often contaminated with P. aeruginosa (42%) than toilets in households of non-infected CF patients (20%; P less than 0.03). The study shows that P. aeruginosa-infected CF patients may harbour the organisms also in the intestinal tract, and may spread the bacteria into toilets.     

Dengue epidemic in Fortaleza, Ceará: randomized seroepidemiologic survey

OBJECTIVE: A seroepidemiological random survey was carried out in Fortaleza city, State of Ceará, Brazil, following an epidemic of dengue virus type 2 (DEN 2), with the purpose of evaluating the frequency of clinical manifestations (signs and symptoms) and the prevalence of dengue infection. METHOD: A questionnaire calling for information on address, sex, age, clinical, epidemiological and economic status was applied to the population, followed by venupuncture collection of 5-10 ml of blood for testing by hemagglutination-inhibition (HI). The sample was calculated to obtain a prevalence of 20% with relative risk of 10% and confidence interval of 95%. All information obtained was analyzed by computer using Epi Info 5.0, Lotus 123, Excel 5.0, and Stata software. RESULTS AND CONCLUSIONS: A total of 1,341 serum samples were obtained from nine Health Districts (SD) and tested by hemagglutination inhibition. Of these, 589 (44%) were positive and 752 (56%) negative. Of the positive results, 93 primary responses (PR) (7%) to DEN-2 and 496 secondary responses (SR) (37%) were observed. The global prevalence in the SD ranged from 21% to 71%. There were 41% (243/589) asymptomatic infections and 59% (346/589) symptomatic infections. Data analysis showed no difference in frequency by sex, age, on schooling, although a highly statistically significant difference was found as between the different social classes, the infection most commonly observed being among people of better social status. The stratification of positive cases showed greater prevalence of AI (p < 0.001) and SI (p < 0.0001) in both sexes, among people with SR rather than PR. The most prevalent symptoms were fever, headache, muscle pains, rash, dizziness, and joint pains. Moreover, itching, retro-bulbar pain, rash, and gingival bleeding, showed statistically significant differences. On the other hand, dizziness and joint pains were more associated in the patients with SR than PR, and statistically significant differences were also observed.     

Immunogenicity and effectiveness of Haemophilus influenzae type b conjugate vaccine in HIV infected and uninfected African children

The quantitative (anti-Hib capsular polysaccharide antibody concentrations; anti-HibPS) and qualitative (bactericidal activity and avidity) aspects in immune responses to Haemophilus influenzae type b polyribosyl ribitol phospshate-CRM(197) conjugate vaccine (HibCV; HibTiter) were evaluated in 66 HIV infected children not receiving anti-retroviral therapy and 127 HIV uninfected children. Surveillance was conducted for invasive Hib disease in a cohort of 39,865 (approximately 6.4% of whom were HIV infected) children from March 1998 to June 2004. HIV infected children had lower anti-HibPS geometric mean antibody concentrations 1 month post-immunisation than HIV uninfected children (P<0.00001) and were less likely to have anti-HibPS antibody concentrations of >or=1.0 microg/ml (RR 0.54; 95% CI 0.43-0.69). A lower proportion of HIV infected children than HIV uninfected children (RR 0.78; 95% CI 0.66-0.93) had measurable anti-Hib serum bactericidal activity (SBA) and the HibPS antibody concentration required for 50% killing of Hib bacteria was greater among HIV infected than HIV uninfected children (P=0.001). The estimated risk of HibCV failure was 35.1-fold greater (95% CI 14.6-84.6) amongst HIV infected than HIV uninfected children.     

Prevalence and spatial distribution of intestinal parasitic infections in a rural Amazonian settlement, Acre State, Brazil

A population-based survey of the prevalence and spatial distribution of intestinal parasitism was carried out in an agricultural settlement in the Amazon Basin of Brazil (Granada, Acre State). More than half (53.4%) of the 429 stool specimens from subjects in all age groups, living in 113 households, had cysts, ova, or larvae of intestinal parasites. The most prevalent parasites were Giardia duodenalis (19.6%) and soil-transmitted helminths (12.7%); 105 (24.5%) subjects were infected with more than one species of parasite. Significant age-related differences in prevalence were only found for G. duodenalis (children < 1 year and adults > 30 years were less affected). Six households (5.3%), situated within a radius of 690m, comprised 48.1% of all subjects harboring soil-transmitted helminths in our study area. Households within this cluster were poorer and more crowded than those outside the cluster. The observed spatial clustering of infections with soil-transmitted helminths provides valuable information for the spatial targeting of sanitary interventions in this area.     

HIV infection among paediatric in-patients in Blantyre, Malawi

To investigate the impact of HIV infection on hospital admission and death we studied children admitted to paediatric medical and surgical wards in Blantyre, Malawi, in March 2000. Unselected children whose parents or guardians consented to HIV testing of the child were recruited and HIV infection was determined by serology, with confirmation in children aged 15 months or less by PCR. We assessed the prevalence of HIV infection by age, clinical diagnosis and outcome of admission. Of 1064 admissions, 991 were tested for HIV infection, and 187 (18.9%) were infected. HIV was most common in children aged less than six months, 53 of 166 (32%). Parents of HIV-infected children were better educated, and more likely to have died, than those of uninfected children. Clinical symptoms and signs were not adequately sensitive or specific to be used for diagnosis of HIV. HIV was common in children with malnutrition (prevalence 40%), lower respiratory tract infection (29%) and sepsis (28%), and less prevalent among children with malaria (11%) or surgical admissions (11%). Almost 30% of HIV-infected children died, compared with 8.9% of uninfected children, and HIV-infected children constituted over 40% of in-patient deaths.     

Influence of socioprofessional conditions on blood pressure levels and hypertension control. Epidemiologic study of 6,665 subjects in the Paris district

A total of 6,665 subjects (3,896 men and 2,769 women) employed by small and medium-sized companies in the Paris region were examined. Mean systolic blood pressure (SBP) was significantly higher in the lowest than in the highest occupational categories (p less than 0.001), even when results were adjusted for age (p less than 0.001) and body mass index (p less than 0.001). Diastolic blood pressure (DBP) differed among the occupational categories (p less than 0.001); the differences were still significant after adjustment for age but not for body mass index, suggesting that the latter might be partly responsible for the differences in DBP. Prevalence of hypertension was 14.7% and was negatively associated with a high occupational category (p less than 0.001). Multivariate analysis confirmed the influence of occupational category on SBP (p less than 0.001). Exposure to noise at work and assembly line work were associated with high SBP (p less than 0.01 for both). Of the subjects with detected hypertension, 65.6% were aware of their illness, and 35.3% were undergoing treatment. Both the percentage of treated patients and compliance with treatment were positively associated with occupational category (p less than 0.01 in both cases). Among women, SBP of treated hypertensives was higher in the lowest than in the highest occupational categories (p less than 0.05). It is suggested that the differences in blood pressure levels observed among occupational categories are partly due to working conditions, and that poor compliance with treatment among the low occupational categories enhances these differences.     

Health and work in rural areas: sugar cane plantation workers in Ribeirão Preto, São Paulo, Brazil

This study is based on an understanding of health and rural labor as a social process related to the characteristics of the agrarian issue in Brazilian society, focusing on sugar cane cutters in northeastern S?o Paulo State, Brazil, and attempting to identify patterns of attrition and reproduction in such labor. Based on direct observations, interviews with laborers and other agents involved in production, and a related bibliographical review, the analysis points to daily exposure of cane cutters to physical, chemical, and biological hazards resulting in various diseases, traumas, and accidents: dermatitis, conjunctivitis, dehydration, cramps, dyspnea, respiratory infections, high blood pressure, and wounds, besides aggravating the biopsychic burden underlying attrition patterns showing up in the spinal column, chest, head, and lumbar pains, nervous breakdowns, and other kinds of psychosomatic manifestations. This study of the work process pointed up its unhealthy working conditions and helped provide an overview of the conditions and means by which capital asserts itself in Brazil - in its self-reproduction process - especially in the agro-industrial sector.     

Efficacy of oxamniquine and praziquantel in the treatment of Schistosoma mansoni infection: a controlled trial

OBJECTIVE: To evaluate the therapeutic efficacy of oxamniquine and praziquantel, the two most clinically important schistosomicide drugs, and to compare the accuracy of faecal examination with the accuracy of oogram in testing for Schistosoma mansoni infection. METHODS: In a triple-masked and randomized controlled trial, 106 patients infected with S. mansoni were randomly allocated to one of three statistically homogeneous groups. One group was given 60 mg/kg praziquantel per day for three consecutive days, another was given two daily doses of 10 mg/kg oxamniquine, and the placebo group received starch. Faecal examinations (days 15, 30, 60, 90, 120, 150, and 180 after treatment) and biopsy of rectal mucosa by quantitative oogram (days 30, 60, 120, and 180) were used for the initial diagnosis and for evaluating the degree of cure. The chi2 test and the Kruskal-Wallis test were used to compare variables in the three groups. Survival analysis (Kaplan-Meier) and the log-rank test were used to evaluate the efficacy of the treatments. FINDINGS: The sensitivity of stool examinations ranged from 88.9% to 94.4% when patients presented with >5000 S. mansoni eggs per gram of tissue (oogram); when the number of eggs dropped to <1000 eggs per gram, sensitivity was reduced (range, 22.7-34.0%). When cure was evaluated by stool examination, oxamniquine and praziquantel had cure rates of 90.3% and 100%, respectively. However, when the oogram was used as an indicator of sensitivity, the oxamniquine cure rate dropped dramatically (to 42.4%), whereas the rate for praziquantel remained high, at 96.1%. CONCLUSIONS: Praziquantel was significantly more effective than oxamniquine in treating S. mansoni infection. The oogram was markedly more sensitive than stool examinations in detecting S. mansoni eggs and should be recommended for use in clinical trials with schistosomicides.