A.M. Tomkins

Vitamin A supplementation in northern Ghana: effects on clinic attendances, hospital admissions, and child mortality

Although most studies on the effect of vitamin A supplementation have reported reductions in childhood mortality, the effects on morbidity are less clear. We have carried out two double-blind, randomised, placebo-controlled trials of vitamin A supplementation in adjacent populations in northern Ghana to assess the impact on childhood morbidity and mortality. The Survival Study included 21,906 children aged 6-90 months in 185 geographical clusters, who were followed for up to 26 months. The Health Study included 1455 children aged 6-59 months, who were monitored weekly for a year. Children were randomly assigned either 200,000 IU retinol equivalent (100,000 IU under 12 months) or placebo every 4 months; randomisation was by individual in the Health Study and by cluster in the Survival Study. There were no significant differences in the Health Study between the vitamin A and placebo groups in the prevalence of diarrhoea or acute respiratory infections; of the symptoms and conditions specifically asked about, only vomiting and anorexia were significantly less frequent in the supplemented children. Vitamin-A-supplemented children had significantly fewer attendances at clinics (rate ratio 0.88 [95% CI 0.81-0.95], p = 0.001), hospital admissions (0.62 [0.42-0.93], p = 0.02), and deaths (0.81 [0.68-0.98], p = 0.03) than children who received placebo. The extent of the effect on morbidity and mortality did not vary significantly with age or sex. However, the mortality rate due to acute gastroenteritis was lower in vitamin-A-supplemented than in placebo clusters (0.66 [0.47-0.92], p = 0.02); mortality rates for all other causes except acute lower respiratory infections and malaria were also lower in vitamin A clusters, but not significantly so. Improving the vitamin A intake of young children in populations where xerophthalmia exists, even at relatively low prevalence, should be a high priority for health and agricultural services in Africa and elsewhere.

Intestinal parasitic infections: a soluble public health problem

Lorenzo Savioli’, Don Bundy’ and Andrew Toni ‘WHO Collaborating Centre on the Epidemiolop of Intestinal Parasites, Department of Biology, Imperial College of Science, Technology and Medicine, London, UK; Centre for International Child Health, Institute of Child Health, University of London, UK

Nutritional status and severity of diarrhoea among pre-school children in rural Nigeria.

The influence of pre-existing malnutrition on the severity of diarrhoea was investigated by assessing attack-rate and duration of diarrhoea in children aged between 6 months and 32 months at the beginning of the rainy season in Malumfashi village area, northern Nigeria. There were 1.4 attacks of diarrhoea per child during the 3 month rainy season and children spent 10.5% of the time with diarrhoea. The frequency of diarrhoea was not increased in underweight (less than 75% weight/age) or stunted (less than 90% height/age) children, but those who were wasted (less than 80% weight/height) experienced 47% more episodes of diarrhoea than those who were not wasted. However, pre-existing malnutrition affected the duration of diarrhoea, which was 33% longer in underweight children, 37% longer in stunted children, and 79% longer in wasted children.

Zinc or multiple micronutrient supplementation to reduce diarrhea and respiratory disease in South African children: a randomized controlled trial.

Background Prophylactic zinc supplementation has been shown to reduce diarrhea and respiratory illness in children in many developing countries, but its efficacy in children in Africa is uncertain. Objective To determine if zinc, or zinc plus multiple micronutrients, reduces diarrhea and respiratory disease prevalence. Design Randomized, double-blind, controlled trial. Setting Rural community in South Africa. Participants Three cohorts: 32 HIV-infected children; 154 HIV-uninfected children born to HIV-infected mothers; and 187 HIV-uninfected children born to HIV-uninfected mothers. Interventions Children received either 1250 IU of vitamin A; vitamin A and 10 mg of zinc; or vitamin A, zinc, vitamins B1, B2, B6, B12, C, D, E, and K and copper, iodine, iron, and niacin starting at 6 months and continuing to 24 months of age. Homes were visited weekly. Outcome Measures Primary outcome was percentage of days of diarrhea per child by study arm within each of the three cohorts. Secondary outcomes were prevalence of upper respiratory symptoms and percentage of children who ever had pneumonia by maternal report, or confirmed by the field worker. Results Among HIV-uninfected children born to HIV-infected mothers, median percentage of days with diarrhea was 2.3% for 49 children allocated to vitamin A; 2.5% in 47 children allocated to receive vitamin A and zinc; and 2.2% for 46 children allocated to multiple micronutrients (Pu200a=u200a0.852). Among HIV-uninfected children born to HIV-uninfected mothers, median percentage of days of diarrhea was 2.4% in 56 children in the vitamin A group; 1.8% in 57 children in the vitamin A and zinc group; and 2.7% in 52 children in the multiple micronutrient group (Pu200a=u200a0.857). Only 32 HIV-infected children were enrolled, and there were no differences between treatment arms in the prevalence of diarrhea. The prevalence of upper respiratory symptoms or incidence of pneumonia did not differ by treatment arms in any of the cohorts. Conclusion When compared with vitamin A alone, supplementation with zinc, or with zinc and multiple micronutrients, did not reduce diarrhea and respiratory morbidity in rural South African children. Trial Registration ClinicalTrials.gov NCT00156832

Fermentation of cereals for reduction of bacterial contamination of weaning foods in Ghana.

Unfermented and fermented maize dough weaning foods prepared by mothers in a Ghanaian village were examined for gram-negative bacilli (GNB) immediately after preparation and during storage to assess the antimicrobial effect of fermentation. GNB were cultured from all samples of unfermented dough (51) and from 16 of 51 samples of fermented dough. The extent of contamination was significantly higher in the unfermented dough than in fermented dough (5.9 [SEM 0.1] vs 4.0 [0.4] log10 colony forming units/g). After 6 h and 12 h storage, a higher proportion of samples of porridge made from unfermented dough contained GNB than did those made with fermented dough (45/51 vs 22/55; 49/51 vs 20/51, respectively) and levels of GNB were significantly higher in the porridge made from unfermented dough after 6 h (4.2 [0.2] vs 3.8 [0.2]). Fermentation of maize dough is an effective method to reduce contamination of maize dough weaning foods with GNB.

Bacterial colonization of jejunal mucosa in giardiasis

Nine of 14 cases of giardiasis and severe malabsorption were found to have numerous bacteria adjacent to the mucosa and within luminal fluid samples from the upper jejunum. Three species of enterobacteria (Klebsiella pneumoniae, Enterobacter cloacae and E. hafniae) were cultured from eight patients and from only one were Bacteroides isolated. Enterobacteria were not cultured from seven of eight patients who had giardiasis but only mild malabsorption (of xylose only) nor from seven patients without malabsorption. Intestinal colonization by enterobacteria may make an important contribution to the development of malabsorption in patients with giardiasis.

COMPARISON OF EDMONSTON-ZAGREB AND SCHWARZ STRAINS OF MEASLES VACCINE GIVEN BY AEROSOL OR SUBCUTANEOUS INJECTION

The serological response to measles vaccine was tested in Bangladesh in groups of infants aged 4-6 months who received equal doses of Edmonston-Zagreb or Schwarz vaccine by subcutaneous injection or by aerosol. Seroconversion (as measured by the haemagglutination test) occurred in 62% of infants receiving Edmonston-Zagreb strain by injection compared with only 37% of those receiving Schwarz strain. Seroconversion occurred in 35% of those given Edmonston-Zagreb and 34% of those given Schwarz vaccine by aerosol. Edmonston-Zagreb strain appears more effective than Schwarz vaccine in this population and further studies are indicated in other populations where early measles immunisation is desirable.

Water supply and nutritional status in rural northern Nigeria

A high incidence of protein energy malnutrition (PEM) was found in a community survey of preschool children in rural northern Nigeria among whom gastro-enteritis is common. Wasting (less than 80% Weight/Height) was more common (37.9%) among those with scanty, unprotected water supplies than in those with copious protected water (10.2%) whereas the incidence of stunting (less than 90% Height/Age)) was similar. Severe coliform contaminatin of all water sources was demonstrable. Even higher numbers of coliforms in foods sampled suggests that other factors related to water supply may be more important than water purity in the genesis of the PEM/gastro-enteritis complex.

Bacterial colonisation of jejunal mucosa in acute tropical sprue.

Fifteen of sixteen Caucasians with acute tropical sprue were founc to have numerous aerobic bacteria closely associated with the mucosal layer of the proximal jejunum. Four species of Enterobacteria were grown in eleven patients, and concentrations were higher in the mucosal patients than in the jejunal fluid. Only one of eight control cases with similar tropical exposure but without mucosal morphological abnormalities had any similar bacteria in the mucosal biopsy. In no case were Bacteroides isolated. Since clinical and biochemical improvement only occurred on treatment with tetracycline when enterobacteria were eliminated from the mucosa, it is suggested that these organisms may be responsible for persisting jejunal abnormalities in tropical sprue.

Effect of fermentation of Ghanaian maize dough on the survival and proliferation of 4 strains of Shigella flexneri

Fermented and non-fermented Ghanaian maize dough was seeded with approximately 10(7) colony forming units of 4 strains of Shigella flexneri which had been isolated from patients with dysentery. In the non-fermented maize dough (pH 6.2) the shigellae were detectable in large numbers for up to 24 h after exposure. In the maize dough that had been fermented for 3 d (pH 3.2) 3 strains were detectable in small numbers for up to 6 h after inoculation. Thereafter none was isolated. The fourth strain, though detectable for up to 24 h after inoculation, had its numbers reduced considerably. This suggests that traditional methods of food preparation using fermentation have important anti-diarrhoeal functions and the current decline in popularity of such food technologies in certain developing countries may increase the risk of childhood diarrhoea.