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).     

Pyridoxine supplementation: effect on lymphocyte responses in elderly persons

The effect of pyridoxine supplementation on lymphocyte responsiveness was investigated in 15 persons aged 65-81 y. Eleven subjects received 50 mg/d pyridoxine HCl (PN). Four subjects received a placebo. Lymphocyte proliferation to T and B cell mitogens, lymphocyte subpopulations with monoclonal antibodies, and plasma pyridoxal 5'-phosphate (PLP) were measured before and after 1 and 2 mo of supplementation. After 1 and 2 mo plasma PLP levels increased by 195 +/- 88 nM and 201 +/- 84 nM, respectively, in subjects receiving PN. With PN supplementation, lymphocyte proliferation increased significantly in response to phytohemagglutinin (p less than 0.01), pokeweed mitogen (p less than 0.01), and Staphylococcus aureus (Cowain I) (p less than 0.05). For PN-treated subjects with low presupplement plasma PLP levels, lymphocyte blastogenesis also increased significantly (p less than 0.01) in response to concanavalin A. Percentages of T3+ and T4+ but not T8+ cells increased significantly (p less than 0.05) in PN-treated subjects. These results suggest that improving vitamin B-6 status is important in stimulating immunocompetence in the elderly.     

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.     

Vitamin E supplementation enhances cell-mediated immunity in healthy elderly subjects

The effect of vitamin E supplementation on the immune response of healthy older adults was studied in a double-blind, placebo-controlled trial. Subjects (n = 32) resided in a metabolic research unit and received placebo or vitamin E (800 mg dl-alpha-tocopheryl acetate) for 30 d. Alpha-tocopherol content of plasma and peripheral blood mononuclear cells (PBMCs), delayed-type hypersensitivity skin test (DTH), mitogen-stimulated lymphocyte proliferation, as well as interleukin (IL)-1, IL-2, prostaglandin (PG) E2, and serum lipid peroxides were evaluated before and after treatment. In the vitamin E-supplemented group 1) alpha-tocopherol content was significantly higher (p less than 0.0001) in plasma and PBMCs, 2) cumulative diameter and number of positive antigen responses in DTH response were elevated (p less than 0.05), 3) IL-2 production and mitogenic response to optimal doses of concanavalin A were increased (p less than 0.05), and 4) PGE2 synthesis by PBMCs (p less than 0.005) and plasma lipid peroxides (p less than 0.001) were reduced. Short-term vitamin E supplementation improves immune responsiveness in healthy elderly individuals; this effect appears to be mediated by a decrease in PGE2 and/or other lipid-peroxidation products.     

Efficacy of Praziquantel Treatment and Schistosoma Mansoni Infection among Primary School Children in Kemisse Town,Northeast Ethiopia

BackgroundSchistosoma mansoni infection is endemic in Ethiopia. The epidemiology of S. mansoni and the efficacy of praziquantel among schoolchildren have not been well documented in different parts of the country including our study area. Therefore, this study aimed to determine the status of S. mansoni infection and evaluate the therapeutic efficacy of praziquantel among school children in northeast Ethiopia.MethodsA comparative cross-sectional study was conducted among 499 children of two preschool children. Stool specimens were collected and microscopically examined using Kato-Katz (41.7 gram) methods. Positive children were treated with a single oral dose of praziquantel at 40 mg/kg body weight. Egg reduction and cure rates were assessed 4 weeks post-treatment to evaluate the therapeutic efficacy of praziquantel against S. mansoni infection.ResultsThe overall prevalence of S. mansoni infection among the schoolchildren was 52.1% with a mean intensity of 546 eggs per gram of stool. Majorities of the S. mansoni infections were moderate to heavy intensity, with only 5.0% light infections. Praziquantel administered at a single oral dose of 40 mg/kg achieved a cure rate of 91.7% and reduced the egg rate by 86.8%. Twenty-one schoolchildren remained infected at 4 weeks post-treatment, among which 6 and 15 children had moderate and light infections, respectively.ConclusionsS. mansoni prevalence among primary school children in Northeast Ethiopia was high, highlighting the need to implement school-based chemotherapy with annual frequency. The efficacy of praziquantel at 40 mg/kg is sufficient to permit continued use in treating S. mansoni-infected schoolchildren.     

Diagnosis of schistosomiasis

Schistosomiasis affects around 200 million persons in the world despite improved knowledge of its epidemiology and physiopathology and significant therapeutic advances. Reliable diagnosis at present is based on observation of the parasite eggs. Schistosoma mansoni causes hepatointestinal schistosomiasis, and S. haematobium causes genitourinary disease. Other species are less frequently observed. The parasites develop in the intrahepatic blood vessels. The females migrate to different parts of the body to lay their eggs, still in the blood vessels. The eggs of different species are of variable size, but all contain a larva called miracidium and all possess a spur. Precise diagnosis is based on the morphologic characteristics of the eggs. As the eggs block different organs, especially the liver, they cause inflammatory granulomas to form. The different species of schistosomas have different geographic distributions that depend partly on the distribution of their mollusk intermediate hosts. S. mansoni and S. haematobium are present in Africa and S. mansoni is also found in the Americas. The eggs of S. haematobium are present most frequently in the urine, while in other species they are found in the stool. The procedure for collecting and preparing the specimens is described. Rectal biopsies obtained during consultations can be examined immediately if facilities are available, and biopsies may also be taken during surgical procedures. The size, color, shape, shell, and spur of eggs of each species are described, and characteristics peculiar to each are noted.     

Modification of vitamin A metabolism in rats fed a copper-deficient diet

The liver is the main storage site of vitamin A and copper. Inverse relationships between copper and vitamin A liver concentrations have been suggested. We have investigated the consequences of a copper-deficient diet on liver and blood vitamin A storage in Wistar rats. Animals were fed either a copper-deficient diet for 45 days from weaning, or an identical diet containing adequate amounts of copper. Concentrations of vitamin A were determined by isocratic high performance liquid chromatography using UV detection. We have observed in the liver of the rats fed a copper-deficient diet a significantly higher mean level of retinyl esters (148 +/- 37 micrograms/g of liver) and retinol (3.3 +/- 1.4 micrograms/g of liver) compared to the mean concentration of the retinyl esters (53 +/- 8.5 micrograms/g of liver) (p less than 0.01) and retinol (1.4 +/- 0.5 micrograms/g of liver) (p less than 0.01) in controls. Opposite results were observed in the serum of the group fed a copper-deficient diet as these rats had a significantly lower level of retinol (22 +/- 4 micrograms/100 ml) compared to the mean concentration in the controls (64 +/- 20 micrograms/100 ml) (p less than 0.01). These findings suggest that a copper-deficient diet may cause defective transport of vitamin A from liver to blood. This experimental model may be useful to further investigate unusual liver vitamin A and copper concentrations observed in children during various hepatobiliary diseases.     

Immunological features in different clinical forms of strongyloidiasis

Serum immunoglobulin levels, skin test response to PPD, lymphocyte surface markers and eosinophil count in peripheral blood were studied in 35 patients with strongyloidiasis diagnosed by stool examination. The patients were divided into three groups based on clinical history, physical examination and laboratory examination: an asymptomatic group (14 patients), a symptomatic group (14 patients) and a group with severe parasitic infection (seven patients). In three of the seven patients with severe strongyloidiasis, massive infection caused by Strongyloides stercoralis had been diagnosed at least once before this study. The IgG levels were significantly lower (p less than 0.05) in patients with severe strongyloidiasis (1180 +/- 529 mg/dl) than in the asymptomatic group (2347 +/- 1224). IgA and IgM levels were also lower in the patients with massive infection when compared to the asymptomatic and symptomatic groups. No decrease of T cells or B cells was found in patients with severe strongyloidiasis. However, the eosinophil count was significantly lower in patients with severe strongyloidiasis than in asymptomatic or symptomatic patients (p less than 0.05). The authors suggest that eosinophils and antibodies may play an important role in the defence mechanism against S. stercoralis larvae.     

Serum concentrations of retinol and retinyl esters in adults in response to mixed vitamin A and carotenoid containing meals

Previous studies using spectrophotometric methods for vitamin A analysis concluded that fasting prior to blood collection is not necessary for determining vitamin A status of children or young adult subjects. We measured the effect of mixed vitamin A and carotenoid containing meals with less than 3, 50, and 100% of the recommended dietary allowance (RDA) for vitamin A on serum concentrations of retinyl esters, retinol, and carotenoids in elderly and young adults after an overnight fast. Retinyl ester concentrations rose significantly in both age groups with a numerically higher rise over baseline in the elderly subjects: 6.0 +/- 0.9 micrograms/dl for elderly (p less than 0.001), 5.0 +/- 0.5 micrograms/dl for young (p less than 0.001) at 50% RDA; 9.0 +/- 1.3 micrograms/dl for elderly (p less than 0.001) and 6.8 +/- 1.6 micrograms/dl for young (p less than 0.05) at 100% RDA. We conclude that in both young and elderly adults, but especially in the elderly, fasting conditions are necessary for the accurate assessment of vitamin A status if spectrophotometric methods are used for measuring vitamin A.     

The role of hygienic bathing after defecation in the transmission of Schistosoma mansoni

Transmission of Schistosoma mansoni depends on fecal eggs reaching water, but the way this happens is poorly understood. We studied the role of hygienic bathing after defecation in the contamination of water with S. mansoni eggs. Individuals in an endemic community in Northern Senegal (n=991) were examined for S. mansoni infection and a random sample (22%) was interviewed about stool disposal practices and hygienic behavior. We assessed the presence and viability of S. mansoni eggs adhering to the peri-anal region of 13 infected volunteers, by counting the miracidia in the water they had used for hygienic washing; for 10 of them (77%) miracidia were demonstrated. From the population infection distribution, average number of defecations per day, proportion of individuals bathing after defecation, and association between miracidial counts and infection intensity, we calculated a daily population miracidial output of approximately 30,000 through hygienic bathing. For comparison, one complete stool reaching the water was calculated to yield approximately 2500 miracidia. Thus, 12 individuals in this population should defecate into the water every day to produce the same number of miracidia as through hygienic bathing. Our results suggest a major role of hygienic bathing after defecation in the transmission of S. mansoni.     

Intestinal parameters in acute murine schistosomiasis mansoni.

Intestinal involvement is very important in acute murine schistosomiasis mansoni. Nevertheless intestinal parameters have not previously been used in assessing the severity of intestinal disease. The present observations demonstrate that in Schistosoma mansoni-infected mice, the mean total egg count of the small intestine and the mean number of eggs per g in the small and the large intestine were higher than the corresponding egg counts in the liver. The increase in weight of the small intestines of infected compared with uninfected mice was greater than the increase in weight of the corresponding livers. The small intestines from infected mice were considerably shorter than those from uninfected mice. These findings argue for the small intestine as a valuable organ for pathophysiological studies in acute murine schistosomiasis mansoni and simple parameters such as total egg count of the small intestine, the number of eggs per g tissue in small and large intestine and the weight and length of the small intestine, are recommended.     

Effects of acute starvation on vitamin A status in rats

Maintenance of vitamin A stores in the body is dependent on a number of basic metabolic processes. These processes, such as protein and carbohydrate metabolism, are disrupted in acute starvation, and, as a result, alterations in vitamin A status may result. We investigated this possibility in 8-week-old Sprague-Dawley male rats. The rats were starved for 24, 48, and 72 hr but had free access to water. At 24 hours of starvation, the plasma retinol concentration was depressed, but not significantly so. After 48 and 72 hours of starvation, however, the plasma retinol concentration decreased to less than half of the control values (61 +/- 4 vs 124 +/- 12 nmol/dl at 72 hours, mean +/- SEM, (p less than 0.005). The hepatic retinoid (retinyl esters + retinol) concentration (nmol/g liver) was increased at 24 and 48 hours of starvation compared to controls (p less than 0.05), and by 72 hours the concentration was 56% greater in starved rats than in fed controls (p less than 0.001). The total hepatic retinoid content (mumol/total liver) was decreased moderately at all periods of starvation compared to controls (p less than 0.05). In both starved and fed animals, the total hepatic content per 100 g body weight, a measure of total vitamin A reserves, was statistically the same. These results demonstrate that acute starvation in rats alters the vitamin A equilibrium between the plasma and hepatic stores without affecting the overall vitamin A reserves.(ABSTRACT TRUNCATED AT 250 WORDS)     

Suppression of granuloma formation around Schistosoma mansoni eggs in severe protein malnutrition: the role of the egg

The role of Schistosoma mansoni eggs in producing suppressed granulomatous response in severe protein malnutrition was studied in mice by the von Lichtenberg technique. Granulomatous response to eggs recovered from infected mice fed on 4% protein diet for four weeks was compared with the response to eggs that were recovered from mice fed on standard control (20% protein) diet in both unsensitized and sensitized normal mice. Granulomatous response to the former was significantly smaller (p less than .01) in unsensitized mice than to the latter. This suggests that the eggs might have responded to the "milieu interne" altered by malnutrition, in a way that its granuloma-inducing capacity differed from what it would be in well nourished mice. It was concluded that suppression of host cellular immunity may not be the only factor that explains suppression of granulomatous response to S. mansoni egg in severe protein malnutrition.     

Egg count variability and sensitivity of a thin smear technique for the diagnosis of Schistosoma mansoni

Variation in daily egg counts, and in counts for samples of the same stool, was investigated in children with Schistosoma mansoni and Ascaris lumbricoides infections, using a thin smear technique. The results indicated that counts vary according to the stool consistency; drier stools from the same person producing up to seven times greater counts than wet ones. The sensitivity of the technique was tested in schoolchildren living in an endemic S. mansoni area, and found to detect all infections with intensities of greater than 50 eggs per gram of stool, after examination of only one slide containing 40mg stool. The sensitivity varied with the intensity of infection. The relevance of these findings to diagnosis in field situations is discussed.     

Increased risk of vitamin B-12 and iron deficiency in infants on macrobiotic diets

The blood iron, vitamin B-12, and folate status of the 1985 birth cohort of Dutch infants aged 10.1-20.4 mo fed macrobiotic diets (n = 50) and matched omnivorous control infants (n = 57) was measured. Fe deficiency (combination of Hb less than 120 g/L, ferritin less than 12 micrograms/L, and FEP greater than 1.77 mumol/L) was observed in 15% of the macrobiotic group but not in the control group (p = 0.003). Plasma vitamin B-12 concentrations in the macrobiotic group were far below those of the control group (geometrical mean: 149 and 404 pmol/L, respectively, p less than 0.001). Plasma folate concentrations were higher in the macrobiotic group (31.6 +/- 11.7 nmol/L) than in the control group (21.1 +/- 8.8 nmol/L, p less than 0.001). In the macrobiotic group mean corpuscular volume, mean corpuscular hemoglobin mass, and mean corpuscular hemoglobin concentration were higher and hematocrit and red blood cells were lower (all p less than 0.05) than in the control group. It is advised to incorporate regular servings of animal foods into the macrobiotic diet to obtain an adequate amount of vitamin B-12.     

Reduced concentration of hepatic alpha-tocopherol in patients with alcoholic liver cirrhosis.

The concentration of alpha-tocopherol was measured in liver biopsy specimens obtained from 83 patients with alcoholic and non-alcoholic liver diseases. The mean hepatic vitamin E content (as alpha-tocopherol) was significantly lower in 23 patients with alcoholic cirrhosis (17.6 +/- 12.1 nmol/mg wet weight liver), compared with 12 patients with normal liver histology (39.2 +/- 29.7 nmol/mg, P less than 0.01). The mean serum concentration of alpha-tocopherol was lower in patients with alcoholic cirrhosis (13.9 +/- 7.0 mumol/l) than in individuals with alcoholic fatty liver (21.3 +/- 9.3 mumol/l, P less than 0.01) and patients with normal liver histology (23.4 +/- 11.6 mumol/l, P less than 0.01). A decreased ratio of serum alpha-tocopherol/total serum lipids was also observed in patients with alcoholic cirrhosis, compared with patients with normal liver histology (P less than 0.05). There was a significant correlation between concentrations of alpha-tocopherol in liver and serum (r = 0.43, P less than 0.001). Furthermore, serum alpha-tocopherol correlated with retinol (r = 0.53, P less than 0.001), selenium (r = 0.45, P less than 0.001), and albumin (r = 0.37, P less than 0.001) in serum. We suggest that the reduced content of hepatic alpha-tocopherol observed in some patients may play a role in ethanol-induced lipid peroxidation.     

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.     

Trichotillometry: the quantitation of hair pluckability as a method of nutritional assessment

In protein-calorie malnutrition, particularly kwashiorkor, ease of hair pluckability is frequently observed. In an attempt to quantitate this manifestation of the disease a calibrated mechanical instrument, referred to as a trichotillometer, was devised and used to determine the force required to epilate individual hairs in 17 adult hospitalized patients with evidence of protein calorie malnutrition and in 16 well-nourished patients. Nutritional status was examined by measuring body weight, triceps skinfold thickness, arm muscle circumference, serum albumin, lymphocyte count, hematocrit, beta-carotene, vitamin nutriture, and hair shaft diameter. Average epilation force was significantly lower in the malnourished patients than in the well nourished group (17.0 g +/- 11.8 versus 38.2 g +/- 11.4, p less than 0.001), with the lowest mean value found in patients categorized as having kwashiorkor (14.8 g). Plucking force correlated significantly and positively with serum albumin, hair shaft diameter, triceps skinfold, arm muscle circumference, weight, hematocrit, beta-carotene; it did not correlate with vitamin status. In order to determine the effect of acute stress on epilation force a subgroup of 18 patients was evaluated before and 1 and 4 days after surgery. Within this time interval epilation force was not significantly altered by the stress of surgery.     

Marginal vitamin A deficiency in pigs experimentally infected with Trichuris suis: a model for vitamin A inadequacy in children.

The development of an experimental model for marginal vitamin A deficiency in humans is of major interest, enabling the elucidation of possible interactions with helminth infections. We established a useful experimental model for human vitamin A deficiency in young pigs; deficiency was induced through a depletion method encompassing both sow and offspring. We report on a 2 x 2 study in which 18-week-old vitamin A deficient pigs and vitamin A sufficient littermates were infected with both of the intestinal nematodes Trichuris suis and Ascaris suum and followed for 14 weeks through 32 weeks of age. Forty-nine pigs were followed with respect to bodyweight, liver biopsies and blood samples for retinol concentration and faecal samples for parasite eggs and worms. Liver and serum concentrations of vitamin A were significantly diminished in the vitamin A deficient (VAD) group as compared to the vitamin A sufficient (VAS) group both before (P < 0.001) and after inoculation with T. suis and A. suum (P < 0.02). A significant correlation between retinol content in micro-biopsy needle samples and gross liver content was found (r = 0.457, n = 48, P = 0.001). The adult T. suis worms in the VAD group were marginally smaller (36.7 vs 40.2 mm; P = 0.08), more orally located (section 2.9 vs 3.9; P = 0.08) and had a higher proportion of males (0.58 vs 0.50; P = 0.08) whereas there were no effects of diet treatment on fecundity. The proportion of pigs with faecal T. suis egg excretion 12 weeks post inoculation (p.i.) was significantly lower in the VAD group compared with the VAS infected group (21 vs 78%; P = 0.036). In addition, faecal T. suis egg excretion was significantly lower in the VAD group at both week 11 (P = 0.040) and week 12 p.i. (P = 0.021). Vitamin A deficiency may have altered the functional integrity of the mucosal intestinal epithelium, disrupting the normally delicate attachment of T. suis and leading to the premature termination of infection. However, a possible antagonistic interaction, if verified, should not preclude interventions to improve vitamin A status, i.e., treatment should accompany anthelmintic treatment.     

Effects of multimicronutrient supplementation on helminth reinfection: a randomized,controlled trial in Kenyan schoolchildren

A randomized, placebo-controlled, double-blind, two-by-two factorial trial was carried out among 977 schoolchildren from 19 primary schools in Nyanza Province, Kenya from February 1995 to February 1996. The interventions were multimicronutrient supplementation (vitamin A, 1000 micrograms; vitamin B1, 1.4 mg; vitamin B2, 1.6 mg; vitamin B6, 1.7 mg; vitamin B12, 2.0 micrograms; folate, 150 micrograms; niacin, 16 mg; vitamin C, 50 mg; vitamin D, 5 micrograms; vitamin E, 8 mg; iron, 18 mg; zinc, 20 mg; copper, 2.0 mg; iodine, 150 micrograms; selenium, 40 micrograms) and multihelminth chemotherapy (albendazole 600 mg in a single dose and/or praziquantel 40 mg/kg in a single dose). This paper reports the effects of the supplementation given on all school days on reinfection with hookworm, Ascaris lumbricoides, Trichuris trichiura and Schistosoma mansoni after 11 months. Baseline prevalence and geometric mean intensity for hookworm, A. lumbricoides, T. trichiura and S. mansoni in all children investigated were 54.7%, 13.8%, 45.6% and 70.0%, respectively and 8.6, 2.7, 5.9 and 19.4 eggs per gram (epg), respectively. Children received a mean of 2.3 multimicronutrient/placebo tablets per school week, giving a compliance rate of 46%. Children given multimicronutrients had a slightly, but significantly, lower intensity of S. mansoni reinfection compared with children given placebo (5.5 epg vs. 7.7 epg, P = 0.047). Multiple linear regression analyses controlling for baseline infection status confirmed this, as children who received micronutrients were reinfected with S. mansoni at only 69% of the intensity of those who received placebo. Multiple logistic regression analyses revealed that micronutrient supplementation was associated with a lower S. mansoni reinfection rate (odds ratio = 0.7) although this was only of borderline significance (P = 0.090). There were no significant differences in reinfection rates or intensities of hookworm, A. lumbricoides and T. trichiura. The effect on S. mansoni infection intensity is particularly interesting given the low compliance, suggesting that full micronutrient supplementation might have a role to play in S. mansoni control programmes.