The time of day and the interval since previous meal are associated with plasma zinc concentrations and affect estimated risk of zinc deficiency in young children in Peru and Ecuador.

BACKGROUND/OBJECTIVES: Plasma zinc concentration is the preferred biomarker of zinc status, but the time of day and time since previous meals can modify the results. Measuring fasting plasma zinc concentration is not feasible among young children, so adjustments need to be developed for interpreting results. Our objective is to develop correction factors to adjust for the effects of time of day and interval since the previous meal when measuring plasma zinc concentrations of young children. SUBJECTS/METHODS: We measured plasma zinc concentrations among young Peruvian (n =297) and Ecuadorian (n=466) children, and constructed regression models adjusting for time of day, interval since previous meal and infections. RESULTS: Plasma zinc concentrations were positively related to the number of hours since the previous meal in the Peru trial (r =0.22, P<0.0001) and negatively related to the time of day of blood sampling in both Peru (r = -0.24, P<0.0001) and Ecuador (r = -0.18, P<0.001). In multivariate models, plasma zinc concentrations were ~2 µg per 100 ml less for each hour later in the morning when blood samples were collected, in both populations, and concentrations were ~1.0 µg per 100 ml greater for every hour since previous meal consumption in Peru. The percentage of children with low plasma zinc concentrations varied according to both these factors. CONCLUSIONS: The time of day and the interval since the preceding meal should be recorded when measuring plasma zinc concentration and incorporated into the statistical analysis and interpretation when assessing population zinc status.

Variation in the costs of delivering routine immunization services in Peru.

OBJECTIVE: Estimates of vaccination costs usually provide only point estimates at national level with no information on cost variation. In practice, however, such information is necessary for programme managers. This paper presents information on the variations in costs of delivering routine immunization services in three diverse districts of Peru: Ayacucho (a mountainous area), San Martin (a jungle area) and Lima (a coastal area). METHODS: We consider the impact of variability on predictions of cost and reflect on the likely impact on expected cost-effectiveness ratios, policy decisions and future research practice. All costs are in 2002 prices in US dollars and include the costs of providing vaccination services incurred by 19 government health facilities during the January-December 2002 financial year. Vaccine wastage rates have been estimated using stock records. FINDINGS: The cost per fully vaccinated child ranged from 16.63-24.52 U.S. Dollars in Ayacucho, 21.79-36.69 U.S. Dollars in San Martin and 9.58-20.31 U.S. Dollars in Lima. The volume of vaccines administered and wastage rates are determinants of the variation in costs of delivering routine immunization services. CONCLUSION: This study shows there is considerable variation in the costs of providing vaccines across geographical regions and different types of facilities. Information on how costs vary can be used as a basis from which to generalize to other settings and provide more accurate estimates for decision-makers who do not have disaggregated data on local costs. Future studies should include sufficiently large sample sizes and ensure that regions are carefully selected in order to maximize the interpretation of cost variation.

Rotavirus diarrhea disease burden in Peru: the need for a rotavirus vaccine and its potential cost savings.

OBJECTIVE: To assess the disease burden of rotavirus diarrhea in Peru as well the need for and the potential cost savings with a rotavirus vaccine in that country. METHODS: To assess the burden of rotavirus diarrhea in Peru, we reviewed published and unpublished reports where rotavirus was sought as the etiologic agent of diarrhea in children. Rotavirus detection rates obtained from these studies were combined with diarrhea incidence rates from a number of national surveys in order to estimate both the burden of rotavirus diarrhea in the country and its associated medical costs. RESULTS: Rotavirus is a significant cause of morbidity and mortality in Peruvian children. In their first 5 years of life, an estimated 1 in 1.6 children will experience an episode of rotavirus diarrhea, 1 in 9.4 will seek medical care, 1 in 19.7 will require hospitalization, and 1 in 375 will die of the disease. Per year, this represents approximately 384,000 cases, 64,000 clinic visits, 30,000 hospitalizations, and 1,600 deaths. The annual cost of medical care alone for these children is approximately US$ 2.6 million--and that does not take into account the indirect or societal costs of the illness and the deaths. CONCLUSIONS: Rotavirus immunization provides the prospect of decreasing the morbidity and mortality from diarrhea in Peru, but a vaccine regimen would have to be relatively inexpensive, a few dollars or less per child. Future cost-effectiveness analyses should explore the total costs (medical as well as indirect or societal) associated with rotavirus diarrhea. Newly licensed vaccines should be tested according to both their ability to avert deaths and their efficacy with fewer than three doses. All three of these factors could increase the cost savings associated with a rotavirus vaccine.

Respiratory symptoms, asthma, exercise test spirometry, and atopy in schoolchildren from a Lima shanty town.

BACKGROUND: Little is known about the associations between symptoms of asthma, pulmonary function tests, and atopy in developing countries. While asthma in children is often associated with atopy, some studies of wheezing illness have found little or no association, leading to suggestions that there are subgroups of wheezing illness. The ISAAC study recently reported that the prevalence of reported asthma symptoms in Lima, Peru was among the highest in the world, but did not report on the atopic status of the subjects. METHODS: A cross sectional survey was conducted of children aged 8-10 years who had previously participated in a cohort study of respiratory and diarrhoeal illnesses in infancy. Questionnaires were administered asking about respiratory symptoms and asthma diagnoses, pulmonary function tests were performed before and after exercise on a treadmill, and atopy was determined from skin prick tests and specific serum IgE levels. RESULTS: A total of 793 children participated in the survey. The prevalence of asthma related symptoms in the last 12 months was 23.2%, but only 3.8% of children reported a recent asthma attack. The mean differences in pretest percentage predicted forced expiratory volume in one second (FEV(1)) were 8.1% (95% CI 2.4 to 13.8) between children who did and did not report an asthma attack in the last 12 months, and 5.3% (95% CI 2.8 to 7.9) in children who did and did not report respiratory symptoms. The corresponding differences in mean percentage fall in FEV(1) after exercise were 3.1% (95% CI -1 to 7.1) and 5.1% (95% CI 3.4 to 6.8). Recent asthma or respiratory symptoms were not associated with atopy in this population (odds ratios 1.29 (95% CI 0.56 to 2.97) and 0.91 (95% CI 0.61 to 1.37), respectively). CONCLUSIONS: Most asthma in these children was unrecognised and mild. Asthma and asthma symptoms in this population do not seem to be related to atopy.

Therapeutic effects of oral zinc in acute and persistent diarrhea in children in developing countries: pooled analysis of randomized controlled trials.

BACKGROUND: Zinc deficiency is prevalent in children in developing countries. Supplemental zinc provides therapeutic benefits in diarrhea. OBJECTIVE: We sought to measure the effect of supplemental zinc given with oral rehydration therapy during recovery from acute or persistent diarrhea. DESIGN: We conducted pooled analyses including all available published and unpublished randomized controlled trials of the effects of supplementary oral zinc in children aged <5 y with acute or persistent diarrhea. We used Cox survival regression analysis to evaluate the overall effect of zinc on continuation of diarrhea and possible differential effects in subgroups divided by sex, age, weight-for-height, and initial plasma zinc concentration. Dichotomous outcomes were analyzed by logistic regression. To assess the effects of excluding studies without original data from the pooled analyses, effect-size was estimated for all studies by using random-effects models. RESULTS: Zinc-supplemented children had a 15% lower probability of continuing diarrhea on a given day (95% CI: 5%, 24%) in the acute-diarrhea trials and a 24% lower probability of continuing diarrhea (95% CI: 9%, 37%) and a 42% lower rate of treatment failure or death (95% CI: 10%, 63%) in the persistent-diarrhea trials. In none of the subgroup analyses were the 2 subgroups of each pair significantly different from each other; however, in persistent diarrhea there tended to be a greater effect in subjects aged <12 mo, who were male, or who had wasting or lower baseline plasma zinc concentrations. CONCLUSION: Zinc supplementation reduces the duration and severity of acute and persistent diarrhea.

Prevention of diarrhea and pneumonia by zinc supplementation in children in developing countries: pooled analysis of randomized controlled trials. Zinc Investigators' Collaborative Group.

OBJECTIVES: This study assessed the effects of zinc supplementation in the prevention of diarrhea and pneumonia with the use of a pooled analysis of randomized controlled trials in children in developing countries. STUDY DESIGN: Trials included were those that provided oral supplements containing at least one half of the United States Recommended Daily Allowance (RDA) of zinc in children <5 years old and evaluated the prevention of serious infectious morbidity through household visits. Analysis included 7 "continuous" trials providing 1 to 2 RDA of elemental zinc 5 to 7 times per week throughout the period of morbidity surveillance and 3 "short-course" trials providing 2 to 4 RDA daily for 2 weeks followed by 2 to 3 months of morbidity surveillance. The effects on diarrhea and pneumonia were analyzed overall and in subgroups defined by age, baseline plasma zinc concentration, nutritional status, and sex. The analysis used random effects hierarchical models to calculate odds ratios (OR) and 95% CIs. RESULTS: For the zinc-supplemented children compared with the control group in the continuous trials, the pooled ORs for diarrheal incidence and prevalence were 0.82 (95% CI 0.72 to 0.93) and 0.75 (95% CI 0.63 to 0.88), respectively. Zinc-supplemented children had an OR of 0.59 (95% CI 0.41 to 0.83) for pneumonia. No significant differences were seen in the effects of the zinc supplement between the subgroups examined for either diarrhea or pneumonia. In the short-course trials the OR for the effects of zinc on diarrheal incidence (OR 0.89, 95% CI 0.62 to 1.28) and prevalence (OR 0.66, 95% CI 0.52 to 0.83) and pneumonia incidence (OR 0.74, 95% CI 0.40 to 1.37) were similar to those in the continuous trials. CONCLUSIONS: Zinc supplementation in children in developing countries is associated with substantial reductions in the rates of diarrhea and pneumonia, the 2 leading causes of death in these settings.

Randomized, community-based trial of the effect of zinc supplementation, with and without other micronutrients, on the duration of persistent childhood diarrhea in Lima, Peru.

OBJECTIVE: To determine whether supplemental zinc, with or without additional micronutrients, affects the severity and duration of persistent childhood diarrhea and the rate of nutritional recovery. DESIGN: The study was a community-based, double-blind, randomized trial implemented in a shanty town in Lima, Peru. Children aged 6 to 36 months with persistent (>/=14 days) diarrhea received daily, for 2 weeks, a placebo (group P, n = 136) or a supplement of 20 mg of zinc, either with (group Z+VM, n = 137) or without (group Z, n = 139) additional vitamins and minerals. Symptoms of illness were recorded daily, and biochemical and anthropometric assessments were completed at baseline and on day 15. RESULTS: The treatment groups were similar at baseline with regard to the characteristics of the presenting episode, anthropometric data, and plasma zinc concentration. The children consumed, on average, 95% (group P), 94% (group Z), or 88% (group Z+VM) of the supplement (P <.001). The plasma zinc concentration did not change significantly from baseline to day 15 in group P (4 microg/dL) but increased by 38 microg/dL in group Z and 14 microg/dL in group Z+VM. The median duration of diarrhea after starting treatment was 1 day; among children who continued to have diarrhea, there was a significant effect of treatment on diarrheal duration (P =.04, analysis of covariance). Specifically, the duration of illness was significantly reduced by 28% in children in group Z (P =.01) and by 33% in girls in group Z+VM (P =.04). There were no differences in the severity of the episode by treatment group. CONCLUSION: There was a significant reduction in the duration of persistent diarrhea in selected subgroups of zinc-supplemented ambulatory patients in this population.

Clinical manifestations and molecular epidemiology of five cases of diarrhoea in children associated with Vibrio metschnikovii in Arequipa, Peru.

In April 1994, Vibrio metschnikovii was isolated from five infants with watery diarrhoea in Arequipa, Peru, as part of a passive cholera surveillance system. The children ranged in age from 11 to 20 months and had acute diarrhoea, with two cases showing moderate dehydration. Two children also had traces of blood in liquid stool. The children were seen at two different hospitals, and no evidence of a common source of infection was found. No additional V. metschnikovii isolates were identified in the remaining surveillance period that covered the rest of 1994 and 1995. However, stool samples were not screened for enteric pathogens other than vibrios. V. metschnikovii strains isolated from stool samples produced opaque and translucent colonies on agar plates, suggesting capsular material. All isolates were resistant to ampicillin, erythromycin and streptomycin. Plasmid analysis revealed a common 200-kb plasmid in isolates from all cases and an additional 2.7-kb plasmid in three of the isolates. Ribotyping of each isolate after restriction with BglI and HindIII endonucleases demonstrated identical ribotyping patterns. The cases reported suggest that V. metschnikovii may be associated with diarrhoea in man by mechanisms so far unknown.

Safety, immunogenicity, and protective efficacy of one and three doses of the tetravalent rhesus rotavirus vaccine in infants in Lima, Peru.

An oral rhesus-human rotavirus tetravalent (RRV-TV) vaccine (10(4) pfu of rhesus rotavirus [type G3] and of 3 human-rhesus reassortants [G1, G2, and G4]) was evaluated in a field trial in Lima, Peru. At 2, 3, and 4 months of age, infants received either a dose of RRV-TV, an initial dose of vaccine followed by a dose of placebo at 3 and 4 months, or a dose of placebo. Rotavirus-specific IgA responses were detected by ELISA in 75% of the three-dose vaccine group, 59% of the one-dose vaccine group (P = .05), and 24% of the placebo group (P < .001): 64%, 48%, and 12% of each group, respectively, had a neutralizing antibody response to at least 1 serotype. Both one and three doses of vaccine failed to induce a significant level of protection against rotavirus diarrhea; however, they did provide some protection (range, 35%-66%) against more severe rotavirus diarrhea, especially for episodes caused by type G1.

The role of the duodenal microflora as a determinant of persistent diarrhoea.

It has been suggested that proliferation of enterobacteriaceae and/or anaerobes in the duodenum of some children with acute diarrhoea determines whether the episode becomes persistent. A review of published studies and the comparison of cultures of duodenal aspirates from Peruvian children with acute and persistent diarrhoea and diarrhoea-free children did not support this hypothesis. Although many children had enterobacteriaceae and/or anaerobes cultured there was no correlation with clinical and nutritional outcome. Age, nutritional status, the environment and the aetiology of the episode were determinants of the duodenal microflora independent of diarrhoea. Culture of the duodenal aspirates did not increase the yield of enteropathogens which were isolated more frequently from stools than from the duodenum. Despite the presence of a single strain or serotype of enterobacteriaceae suggesting that these bacteria were colonizing the duodenum, we were unable to demonstrate any adherence mechanisms in the majority of them. Two of ten bacteria with no other evidence of virulence caused diarrhoea in the RITARD rabbit model.

Lactose feeding during persistent diarrhoea.

Lactose intolerance is a recognized complication of some episodes of diarrhoea. Whereas it is of clinical importance in relatively few children with acute diarrhoea it seems to be a more common problem in children presenting with persistent diarrhoea, especially in malnourished children with severe diarrhoea. We describe a recent study which also demonstrated adverse clinical and nutritional consequences in the majority of children with mild but persistent diarrhoea consuming 6 g lactose/kg body weight/d. It is desirable to identify these children who need to reduce their lactose intake in order to limit unnecessary dietary changes which are expensive to implement and/or nutritionally disadvantageous. Admission clinical characteristics were analyzed for their ability to predict clinical outcome in a group of 33 children with persistent diarrhoea taking a lactose-containing diet. The results of tests of stool reducing substances and a lactose breath hydrogen test (LHBT) were analyzed in the same group whose clinical management had been independent of the test results. Eighty-nine percent of children who deteriorated had one of the following characteristics: age < 12 months, weight-for-height less than -2 SD below NCHS norms or fever > 37 degrees C. Children who unequivocally improved while continuing to take lactose could not be selected without the risk of including children who deteriorated. Neither tests of stool reducing substances nor the LBHT improved the predictive value of simple clinical parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Virulence properties of Enterobacteriaceae isolated from the small intestine of children with diarrhea.

Enterobacteriaceae isolated from the duodena of Peruvian children with persistent diarrhea (PD) have been examined for virulence factors and compared with Enterobacteriaceae isolated from children with acute diarrhea, those convalescent from PD and diarrhea-free controls. Escherichia coli were isolated from 42 of 186 (23%) of the aspirates. All 11 children with PD in whom multiple E. coli colonies were examined were colonized by a single serotype. DNA probes identified enterotoxigenic E. coli in 2 of 89 (2.2%) PD aspirates and 2 of 38 (5.3%) acute diarrhea aspirates and enteroaggregative E. coli in one PD and one control aspirate. Strains positive with the enteropathogenic E. coli adherence factor probe were identified from 2 of 89 (2.2%) patients with PD and 1 of 34 (2.9%) controls. A subset of 12 E. coli strains failed to show adhesion to human duodenal enterocytes although 5 of 9 showed sparse but polar attachment to ileal cells from a child with short bowel syndrome and PD. Three of 10 Enterobacteriaceae (two E. coli, one Klebsiella species) caused diarrhea in the reversible ileal tie adult rabbit model. Colonization with virulent Enterobactericeae did not explain the majority of episodes of PD. Examination of these duodenal bacteria in the rabbit model revealed some that caused diarrhea but were not recognized pathogens.

Surveys of human enterotoxigenic Escherichia coli from three different geographical areas for possible colonization factors.

Enterotoxigenic Escherichia coli (ETEC) from Burma, central Africa (Rwanda and Zaire) and Peru, were screened by enzyme-linked immunoassays for the colonization factor antigens (CFAs) and putative colonization factors (PCFs): CFA/I, CFA/II, which consists of three coli surface-associated (CS) antigens, CS1, CS2 and CS3, CFA/III, CFA/IV (CS4, CS5, CS6), CS7, PCFO9, PCFO159. H4, PCFO166, and CS17. The highest proportion of ETEC with identifiable colonization factors (71%) were found in the strains from Burma, which were mainly positive for CFA/I (38%), but strains producing CFA/II (4%), CFA/IV (11%), CS7 (10%), CS17 (4%), PCFO159, H4 (2%) and PCFO166 (2%) were also found. Sixty-nine percent of the ETEC from central Africa were positive for known colonization factors. While CFA/I positive strains were important (12%), a higher number of ETEC producing CFA/IV (33%) and CS17 (24%) were found. Fifty-two percent of the Peruvian strains produced identifiable colonization factors. The largest group of strains produced antigens of the CFA/IV complex (17%), while ETEC producing CFA/II (6%), CFA/III and CS6 (2%), CS7 (6%), PCFO9 (6%), PCFO166 (8%) and CS17 (7%) were also found. These surveys show that there is a considerable variation in the proportions and types of colonization factor found in different geographical areas. From 29 to 48% of the ETEC did not possess an identifiable colonization factor. These were particularly of the LT only producing type. These results have important implications for vaccine formulation.

Lack of a role of the duodenal microflora in pathogenesis of persistent diarrhea and diarrhea-related malabsorption in Peruvian children.

Although few episodes of diarrhea last longer than 14 days these episodes are particularly associated with growth faltering and malnutrition. We have examined the role of the duodenal microflora in prolonging diarrhea in Peruvian children ages 3 to 36 months by comparing the microflora in 89 children with persistent diarrhea, 38 children with acute diarrhea and 34 diarrhea-free controls from the same environment. Bacteria were retrieved from 93% of all aspirates, including 94% of those from controls. There were no significant differences among the 3 groups with respect to total bacterial count, to the proportion of children with duodenal Enterobacteriaceae and to the proportion with anaerobes, lending no support to the hypothesis that proliferation of bacteria in the small intestine during the acute illness prolongs diarrhea. When only children older than 18 months were compared, anaerobes were cultured more frequently from those with persistent diarrhea than from controls, but the presence of anaerobes was not associated with adverse clinical outcome. Although malabsorption, especially steatorrhea, was common, there was no association between elevated bacterial counts and fecal loss of nutrients in 69 children who received the same diet. In this population steatorrhea could not be attributed to bacterial overgrowth.

Clinical and nutritional consequences of lactose feeding during persistent postenteritis diarrhea.

In a double-blind prospective trial, 64 children, 3 to 36 months of age, who had diarrhea for at least 14 days were randomly assigned to receive either a milk-based diet containing 6 g/kg of body weight per day of lactose or the same diet in which the lactose was greater than 95% prehydrolyzed with beta-galactosidase. Clinical and nutritional outcomes were compared. The groups were similar at the start of the study. Four of 33 patients (12.1%) in the lactose group were considered to have treatment failure because of excessive purging with or without refusal to accept the diet, compared with 1 of 31 patients (3.2%) in the hydrolyzed lactose group (P = .20). Among successfully treated boys, fecal excretion was initially similar, but on days 3 to 5 of the trial the lactose group purged a mean 74.4 g/kg per day (95% confidence limits 17.8, 131.0) compared with 42.0 g/kg per day (95% confidence limits 11.4, 72.6) in the hydrolyzed lactose group (P less than .01). Diarrhea stopped within 30 hours of hospital admission in 11 children in the hydrolyzed lactose group (35.5%) compared with 1 child in the lactose group (3.3%) (P less than .001). Fecal excretion of carbohydrate, nitrogen, and energy was significantly greater in lactose group (P less than .01), but there were no significant differences in fat excretion or in incremental weight change during hospitalization. Feeding lactose-containing nonhuman milk as the sole nutrient source to children with persistent diarrhea resulted in substantially greater purging which was sufficiently severe to increase the risk of dehydration in these children.

Bacterial contamination of the small intestine of infants with enteropathogenic Escherichia coli and other enteric infections: a factor in the aetiology of persistent diarrhoea?

The duodenal microflora was studied during the first week of diarrhoea in 40 infants with acute infectious diarrhoea of different aetiologies and compared with that in a convalescent group and a group in whom diarrhoea of known aetiology had persisted for more than 14 days after an acute onset. In the acute phase 16 of the 40 infants had more than 10(4) colony forming bacteria/ml, predominantly upper respiratory commensals. In over half of the infants infected with enteropathogenic Escherichia coli a faecal type flora was found in the duodenum. This flora included the enteropathogenic E coli serotype isolated from the stool in three quarters of cases. Infants with persisting diarrhoea had significantly more faecal type bacteria in the duodenum than either those with acute diarrhoea or the convalescent group. In addition, there was a significant further increase in Enterobacteriaceae in infants whose persistent diarrhoea occurred after infection with enteropathogenic E coli. Infections with enteropathogenic E coli may have a predilection for disturbing the duodenal microflora, which may contribute to the development of persistent diarrhoea.