Chimney stoves modestly improved indoor air quality measurements compared with traditional open fire stoves: results from a small-scale intervention study in rural Peru.

Nearly half of the world's population depends on biomass fuels to meet domestic energy needs, producing high levels of pollutants responsible for substantial morbidity and mortality. We compare carbon monoxide (CO) and particulate matter (PM2.5) exposures and kitchen concentrations in households with study-promoted intervention (OPTIMA-improved stoves and control stoves) in San Marcos Province, Cajamarca Region, Peru. We determined 48-h indoor air concentration levels of CO and PM2.5 in 93 kitchen environments and personal exposure, after OPTIMA-improved stoves had been installed for an average of 7 months. PM2.5 and CO measurements did not differ significantly between OPTIMA-improved stoves and control stoves. Although not statistically significant, a post hoc stratification of OPTIMA-improved stoves by level of performance revealed mean PM2.5 and CO levels of fully functional OPTIMA-improved stoves were 28% lower (n = 20, PM2.5, 136 µg/m(3) 95% CI 54-217) and 45% lower (n = 25, CO, 3.2 ppm, 95% CI 1.5-4.9) in the kitchen environment compared with the control stoves (n = 34, PM2.5, 189 µg/m(3), 95% CI 116-261; n = 44, CO, 5.8 ppm, 95% CI 3.3-8.2). Likewise, although not statistically significant, personal exposures for OPTIMA-improved stoves were 43% and 17% lower for PM2.5 (n = 23) and CO (n = 25), respectively. Stove maintenance and functionality level are factors worthy of consideration for future evaluations of stove interventions.

Genotypic and phenotypic characterization of enterotoxigenic Escherichia coli strains isolated from Peruvian children.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of childhood diarrhea. The present study sought to determine the prevalence and distribution of toxin types, colonization factors (CFs), and antimicrobial susceptibility of ETEC strains isolated from Peruvian children. We analyzed ETEC strains isolated from Peruvian children between 2 and 24 months of age in a passive surveillance study. Five E. coli colonies per patient were studied by multiplex real-time PCR to identify ETEC virulence factors. ETEC-associated toxins were confirmed using a GM1-based enzyme-linked immunosorbent assay. Confirmed strains were tested for CFs by dot blot assay using 21 monoclonal antibodies. We analyzed 1,129 samples from children with diarrhea and 744 control children and found ETEC in 5.3% and 4.3%, respectively. ETEC was more frequently isolated from children >12 months of age than from children <12 months of age (P < 0.001). Fifty-two percent of ETEC isolates from children with diarrhea and 72% of isolates from controls were heat-labile enterotoxin (LT) positive and heat-stable enterotoxin (ST) negative; 25% and 19%, respectively, were LT negative and ST positive; and 23% and 9%, respectively, were LT positive and ST positive. CFs were identified in 64% of diarrheal samples and 37% of control samples (P < 0.05). The most common CFs were CS6 (14% and 7%, respectively), CS12 (12% and 4%, respectively), and CS1 (9% and 4%, respectively). ST-producing ETEC strains caused more severe diarrhea than non-ST-producing ETEC strains. The strains were most frequently resistant to ampicillin (71%) and co-trimoxazole (61%). ETEC was thus found to be more prevalent in older infants. LT was the most common toxin type; 64% of strains had an identified CF. These data are relevant in estimating the burden of disease due to ETEC and the potential coverage of children in Peru by investigational vaccines.

Meeting Report: WHO Workshop on modelling global mortality and aetiology estimates of enteric pathogens in children under five. Cape Town, 28-29th November 2018.

Investment in vaccine product development should be guided by up-to-date and transparent global burden of disease estimates, which are also fundamental to policy recommendation and vaccine introduction decisions. For low- and middle-income countries (LMICs), vaccine prioritization is primarily driven by the number of deaths caused by different pathogens. Enteric diseases are known to be a major cause of death in LMICs. The two main modelling groups providing mortality estimates for enteric diseases are the Institute for Health Metrics and Evaluation (IHME) at the University of Washington, Seattle and the Maternal Child Epidemiology Estimation (MCEE) group, led by Johns Hopkins Bloomberg School of Public Health. Whilst previous global diarrhoea mortality estimates for under five-year-olds from these two groups were closely aligned, more recent estimates for 2016 have diverged, particularly with respect to numbers of deaths attributable to different enteric pathogens. This has impacted prioritization and investment decisions for vaccines in the development pipeline. The mission of the Product Development for Vaccines Advisory Committee (PDVAC) at the World Health Organisation (WHO) is to accelerate product development of vaccines and technologies that are urgently needed and ensure they are appropriately targeted for use in LMICs. At their 2018 meeting, PDVAC recommended the formation of an independent working group of subject matter experts to explore the reasons for the difference between the IHME and MCEE estimates, and to assess the respective strengths and limitations of the estimation approaches adopted, including a review of the data on which the estimates are based. Here, we report on the proceedings and recommendations from a consultation with the working group of experts, the IHME and MCEE modelling groups, and other key stakeholders. We briefly review the methodological approaches of both groups and provide a series of proposals for investigating the drivers for the differences in enteric disease burden estimates.

Validation of five-colony pool analysis using multiplex real-time PCR for detection of diarrheagenic Escherichia coli.

Five Escherichia coli colonies/patient were studied to evaluate the reliability of a multiplex real-time PCR assay for detection of diarrheagenic Escherichia coli groups, using a pool of five colonies rather than individual colonies. Sensitivity and specificity were 98% and 100%, respectively, at a fifth of the cost of the individual colony analysis.

Improving household air, drinking water and hygiene in rural Peru: a community-randomized-controlled trial of an integrated environmental home-based intervention package to improve child health.

Background: Diarrhoea and acute lower respiratory infections are leading causes of childhood morbidity and mortality, which can be prevented by simple low-cost interventions. Integrated strategies can provide additional benefits by addressing multiple health burdens simultaneously. Methods: We conducted a community-randomized-controlled trial in 51 rural communities in Peru to evaluate whether an environmental home-based intervention package, consisting of improved solid-fuel stoves, kitchen sinks, solar disinfection of drinking water and hygiene promotion, reduces lower respiratory infections, diarrhoeal disease and improves growth in children younger than 36 months. The attention control group received an early child stimulation programme. Results: We recorded 24 647 child-days of observation from 250 households in the intervention and 253 in the attention control group during 12-month follow-up. Mean diarrhoea incidence was 2.8 episodes per child-year in the intervention compared with 3.1 episodes in the control arm. This corresponds to a relative rate of 0.78 [95% confidence interval (CI): 0.58-1.05] for diarrhoea incidence and an odds ratio of 0.71 (95% CI: 0.47-1.06) for diarrhoea prevalence. No effects on acute lower respiratory infections or children's growth rates were observed. Conclusions: Combined home-based environmental interventions slightly reduced childhood diarrhoea, but the confidence interval included unity. Effects on growth and respiratory outcomes were not observed, despite high user compliance of the interventions. The absent effect on respiratory health might be due to insufficient household air quality improvements of the improved stoves and additional time needed to achieve attitudinal and behaviour change when providing composite interventions.

Potential magnitude of the misclassification of a population's trace element status due to infection: example from a survey of young Peruvian children.

To examine the effects of concurrent infection on population-based assessment of trace element status, we collected data on clinical signs and laboratory indicators of infection when obtaining blood for serum zinc, copper, and ferritin analyses in 153 Peruvian children aged 11-19 mo. Fifty-two (34.7%) of the children had some reported sign of infection and 43 (28.3%) had elevated C-reactive protein concentrations or leukocytosis. Children with any evidence of infection had marginally lower mean (+/- SD) serum zinc concentrations (7.0 +/- 2.3 vs 7.5 +/- 2.0 mumol/L, P = 0.16) and significantly greater serum copper (24.7 +/- 4.7 vs 22.7 +/- 4.2 mumol/L, P = 0.006) and serum ferritin concentrations (10.0 +/- 12.9 vs 3.9 +/- 4.4 micrograms/L, P < 0.001) than did those without infections. Infection caused an underestimation in the rate of low copper status by 1 percentage point and low iron status by 12 percentage points. Thus, the effect of concurrent infections is of variable magnitude and may differ by nutrient, nutritional status of the population, and prevalence and severity of infections.

Breast milk or animal-product foods improve linear growth of Peruvian toddlers consuming marginal diets.

Although breast-feeding is widely accepted as important for infant health, its benefits during the second year of life have been questioned. We analyzed data from 107 breast-fed and weaned Peruvian children living in a periurban community to determine whether breast milk contributed to improved linear growth between 12 and 15 mo of age. Breast-feeding frequency was self-reported; intakes of complementary foods and animal products were estimated from a food-frequency survey. Multivariate-linear-regression analysis was used to predict the length of the children at 15 mo of age. Determinants of length included length and weight-for-length at 12 mo of age (US National Center for Health Statistics standards), interval between 12- and 15-mo measurements, breast-feeding frequency, incidence of diarrhea, and intakes of complementary and animal-product foods. Complementary foods, animal-product foods, and breast milk all promoted toddlers' linear growth. In subjects with low intakes of animal-product foods, breast-feeding was positively associated (P < 0.05) with linear growth. There was a 0.5-cm/3 mo difference in linear growth between weaned toddlers and children who consumed the average number of feedings of breast milk. Linear growth was also positively associated with intake of animal-product foods in children with low intakes of complementary foods. The negative association between diarrhea and linear growth did not occur in subjects with high complementary-food intakes. When the family's diet is low in quality, breast milk is an especially important source of energy, protein, and accompanying micronutrients in young children. Thus, continued breast-feeding after 1 y of age, in conjunction with feeding of complementary foods, should be encouraged in toddlers living in poor circumstances.

PIP: The contribution of prolonged breast feeding to linear growth at 12-15 months of age was investigated in 107 breast-fed and weaned toddlers from a low-income neighborhood in Lima, Peru. The median duration of breast feeding in this sample was 17.1 months; by 15 months, 46 children had been weaned. The prevalence of stunting (length-for-age score -2 SD below the reference standard) was 17.8% at 12 months and 24.3% at 15 months; no child was wasted. Complementary foods, animal product foods, and breast milk all promoted toddlers' linear growth. In children with low intakes of animal product foods, breast feeding was positively associated with linear growth at 15 months (p 0.05). There was a 0.5 cm/3 months difference in linear growth between weaned toddlers and those who consumed the average number (6.3/day) of breast feeds. Linear growth was further positively associated with intake of animal product foods in children with low intakes of complementary foods. The negative association between diarrhea and linear growth did not occur in children with high intakes of complementary foods. When the household diet is of poor quality, breast feeding is an especially important source of energy, protein, and micronutrients in toddlers and should be continued beyond 12 months of age in conjunction with the provision of complementary foods. Breast milk not only added to the total diet of these young children, but also potentiated the beneficial effects of complementary foods consumed by increasing their growth promotion capacity.

Delayed cutaneous hypersensitivity: epidemiologic factors affecting and usefulness in predicting diarrheal incidence in young Peruvian children.

Cell-mediated immunity, as assessed by delayed cutaneous hypersensitivity, can be diminished by malnutrition and viral infections. In turn, decreased immune functioning might lead to more frequent or more severe infectious diseases. Delayed cutaneous hypersensitivity was assessed in young Peruvian children by simultaneous application of seven standardized antigens and a negative control (Multitest CMI). Response to tuberculin was frequent and was higher in children vaccinated with Bacillus Calmette-Guérin, response to tetanus or diphtheria toxoids was also good, especially in children who had received at least two doses of diphtheria-tetanus toxoids-pertussis vaccine. Two summary assessments, the number of positive responses and the sum of indurations of all positive responses provided useful measures of delayed cutaneous hypersensitivity. Responsiveness, as assessed by these summary measures, was inversely related to the incidence of diarrhea, identified by household surveillance for the 6 months after the skin test. Undernutrition, as assessed by weight for age or length for age, was also a significant determinant of the incidence of diarrhea, but not the duration of episodes, in this group of study children. Depressed cell-mediated immunity and malnutrition may be important risk factors for diarrhea in developing country children.

Incidence of Vibrio cholerae O1 diarrhea in children at the onset of cholera epidemic in periurban Lima, Peru.

OBJECTIVE: To determine the incidence of Vibrio cholerae O1-associated diarrhea in children during the onset of the 1991 cholera epidemic in Peru. METHODS: Stool cultures were obtained from children (mean age, 26 months) participating in a prospective community-based study of diarrhea in a periurban community in Lima between February and May, 1991. RESULTS: Of the 409 diarrheal episodes cultured V. cholerae O1 was isolated in 14 (3.4%) episodes. This represented an incidence of 0.11 episode per child year, higher than previously reported rates in children from endemic cholera areas. Most cases were mild; only 1 case required hospitalization. CONCLUSIONS: Our study indicates that from the beginning of this epidemic, V. cholerae O1 caused diarrhea in children as well as adults and should therefore be considered as one of the possible pathogens when children from a cholera-affected area develop diarrhea.

Reappraisal of the Peruvian and Brazilian lower titer tetravalent rhesus-human reassortant rotavirus vaccine efficacy trials: analysis by severity of diarrhea.

OBJECTIVES AND METHODS: With the purpose of better understanding the efficacy of the lower titer [4 x 10(4) plaque-forming units (pfu)] tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV) against diarrheal episodes of different severities, the Peruvian and Brazilian efficacy data were reanalyzed with a 20-point scoring system. Mild, moderate/severe and very severe rotavirus diarrhea were scored as 0 to 8, 9 to 14 and >14, respectively. RESULTS: In the Peruvian study one dose of vaccine yielded 64% (P = 0.04) protection against pure cases of rotavirus disease (i.e. those in which no other enteropathogen was found) with clinical scores ranging from 9 to 14. Protective efficacy against very severe rotavirus gastroenteritis could not be assessed because of the small number of cases. In Brazil there was a trend in preventing "all" and "pure" cases of rotavirus diarrhea scored 9 to 14 (44%, P = 0.06, and 45%, P = 0.08, respectively) and the vaccine was 75% (P = 0.02) protective against pure rotavirus diarrhea scored >14. No protection was observed for mild rotavirus diarrhea (scores <9). These data were compared with those from trials in Venezuela (4 x 10(5) pfu/dose), US (4 x 10(4) pfu/dose and 4 x 10(5) pfu/dose) and Finland (4 x 10(5) pfu/dose). Combining the Peruvian (one dose, pure cases) and Brazilian studies together, the levels of protection against 9- to 14-scored rotavirus diarrhea are comparable with those from the Venezuelan (47%) and American (57, 57 and 65%) efficacy trials. In Brazil the level of protection (75%) against pure, >14-scored rotavirus diarrhea is similar to the efficacy rates yielded in the three US trials (82, 80 and 69%) and the Finnish trial (100%) for episodes of the same severity. CONCLUSIONS: Our reanalysis provides evidence that, at least against moderate/severe rotavirus gastroenteritis, RRV-TV, 4 x 10(4) pfu/dose is potentially as efficacious as RRV-TV, 4 x 10(5) pfu/dose, even in settings with very high rotavirus disease burden. The reanalysis of the Peruvian data suggests that one and three vaccine doses may yield similar efficacy rates. It is also suggested that vaccine efficacy against most severe episodes in Peru and Brazil was not evident because of the trial design used in those studies (i.e. prospective, active home surveillance rather than a catchment trial), resulting in too few cases of severe disease even in the placebo group. To confirm these findings, future trials with this vaccine are necessary in developing countries with high diarrhea morbidity rates. These trials should use catchment designs and focus on the evaluation of the efficacy of one or three doses of RRV-TV against moderate to severe/very severe rotavirus diarrhea.

Validity of a respiratory questionnaire to identify pneumonia in children in Lima, Peru.

We conducted a nested case-control study utilizing cases of clinical pneumonia identified in a community-based prospective surveillance study of children under 3 years of age in order to test the validity of a survey questionnaire. Three types of sex- and age-matched concurrent controls were selected from the surveillance population: acute respiratory infection (ARI) clinic controls. ARI community controls and healthy community controls. Survey interviews were scheduled at random for any of four consecutive 7-day periods after the diagnosis of the case. The questionnaire covered a 30-day recall period. The combination of cough with fast breathing or shortness of breath, and with fever, provided the highest positive predictive value for pneumonia. The sensitivity of some questions dropped when the interview took place more than 15 days after the diagnosis of the case. However, the utilization of a 15-day recall period did not increase the positive predictive value of the survey. We conclude that in this trained population under surveillance, a survey questionnaire utilizing a 30-day recall period and using the combination of cough, fast breathing or shortness of breath and fever to define episodes with a high likelihood of pneumonia, offers an acceptable tool for the monitoring and evaluation of respiratory control programmes. This questionnaire needs further evaluation in an untrained population and in other regions before it can be adopted for use in ARI control programmes.

An evaluation of lot quality assurance sampling to monitor and improve immunization coverage.

Quality assurance sampling techniques with small samples offer a method of monitoring performance of health services in small health areas, and of identifying areas with poor performance in which remedial actions need to be targetted. Lot Quality Assurance Sampling methods were used to assess the coverage resulting from three immunization campaigns in rural and urban areas in the mountains of Peru. Application of these methods in 12 health areas with populations of 538 to 15 780 by Ministry of Health personnel proved feasible and could be used to identify areas with poorer vaccination coverage. Further discussion about possible reasons for poor coverage led to corrective actions in these health areas and an improvement in overall coverage from 78% to 88% in a three-month period. These quality assurance methods are a useful supervisory tool to improve health programme performance.

Association of breastfeeding and stunting in Peruvian toddlers: an example of reverse causality.

BACKGROUND: Child feeding recommendations include breastfeeding beyond 12 months, however, some researchers have reported increased rates of malnutrition in breastfed toddlers. A negative association between growth and breast-feeding may reflect reverse causality; that is, the outcome (growth) is a determinant of the predictor (breastfeeding), and not vice versa. We examined this question with data from 134 Peruvian toddlers. METHODS: A linear regression analysis predicted length at the age of 15 months by length at 12 months, study interval, and 12-14.9-month breastfeeding, complementary food intake, and diarrhoeal incidence. This analysis defined the association between breastfeeding and linear growth. To elucidate the direction of the effect between breastfeeding and linear growth, logistic regression was used to predict the probability of weaning by the end of 14 months. Determinants included weight-for-age (W/A) at 12 months, complementary food intake at 9-11.9 months, and change in diarrhoeal incidence between 9 and 14.9 months. RESULTS: There was a significant (P < 0.01) interaction of breastfeeding, diarrhoeal incidence, and complementary food intake on length at 15 months. Increased breastfeeding was associated with a 1.0 cm decrease in length gain when dietary intake was low and diarrhoeal morbidity was high, implying that breastfeeding is harmful. The logistic analysis, however, demonstrated that the risk of weaning decreased only when W/A and dietary intake were low and diarrhoeal morbidity was high. CONCLUSIONS: The negative association between breastfeeding and linear growth reflected reverse causality. Increased breastfeeding did not lead to poor growth; children's poor growth and health led to increased breastfeeding. Children's health must be considered when evaluating the association of breastfeeding with anthropometric outcomes.

PIP: There has been a perplexing finding, in many developing countries, of increased rates of stunting and growth faltering in breast-fed toddlers receiving complementary foods relative to their non-breast-fed counterparts. Longitudinal data on 134 children 12-15 months of age from Lima, Peru, were used to investigate the hypothesis that the negative association between growth and breast feeding reflects reverse causality. The toddlers were participants in a broader persistent diarrhea surveillance survey conducted during 1985-87. 72.9% of children were breast-fed beyond 12 months (median duration, 16.8 months). Anthropometric measurements revealed stunting in 19.4% of toddlers at 12 months and in 29.1% at 15 months. Linear growth between 12 and 15 months had a complex relationship with breast feeding, diarrhea, and dietary factors. Increased breast feeding was associated with a 1.0 cm decrease in length gain between 12 and 15 months when dietary intake was low and diarrheal morbidity was high. However, logistic analysis demonstrated that mothers whose children had low dietary intakes, low weight-for-age, and increased incidence of diarrhea were less likely to wean their infants at 12 and 14 months. This finding that mothers modified their children's feeding practices according to the child's health and growth status supports a reverse causality process in which poor growth is a determinant rather than a result of breast feeding.

Diarrhoea--defining the episode.

BACKGROUND: There is still no consensus on the appropriate definition of an 'episode' of diarrhoea, even though it has been shown that the choice of definition has a major impact on reported incidence rates. Previous work has focused on the observed distribution of illness episodes in time but has not attempted to determine whether the patterns observed depart from those expected by chance. METHODS: A simple theoretical model of the distribution of illness episodes is developed, based on the concept of a 'trigger event'. The model incorporates elements relating to the duration of symptoms, inter-individual variation in incidence rates and seasonality. Appropriate parameters for the model are derived from two empirical datasets. RESULTS: It is shown that short intervals between one aetiologically distinct period of diarrhoea and the next will frequently occur by chance, especially in circumstances where high incidence rates and within-child clustering of illness prevail. The duration of symptoms will have no effect on the length of intervals between periods of illness, and seasonality is unlikely to have a major impact. Over 10% of all non-initial trigger events might be expected to occur during the course of a pre-existing period of diarrhoea, and would not therefore be identified in a study based on reported symptoms. CONCLUSIONS: The findings of previous studies, suggesting that 2 or 3 days without symptoms will generally mark a new episode of diarrhoea, are endorsed. Modelling the expected distribution of illness in time may help to highlight structural or analytical problems with empirical datasets.

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.

Defecation practices of young children in a Peruvian shanty town.

Little is known about feces disposal practices, their determinants and feasibility for change, despite their importance in the control of diarrheal diseases. We report here the results of formative research for the development of an intervention to promote sanitary disposal of feces of young children. The study was conducted in a densely populated shanty town area of Lima, where water and sanitation systems are scarce. In-depth interviews were undertaken with mothers, husbands and community leaders. Group discussions were held with mothers in order to validate findings from the interviews, investigate particular topics further and explore reactions to possible intervention strategies. The principal defecation sites for young children were diapers, potties, the ground in or near the home, the hill, latrines and flush toilets. The main determinants found were the age of the child, the effort required by the method, perceptions of dirtiness and the availability of resources. Almost all children under one year of age use diapers but the high resource cost of diaper washing is a strong motivation for mothers to move their children on as early as possible. Potties were considered the most socially acceptable and 'hygienic' defecation method for children between one and three years of age. Nevertheless, defecation directly onto the ground is common at this age. Potty training is deemed to be quite difficult and the long term achievements are determined by the initial training success. In most cases, the training process is authoritative and inconsistent. The use of latrines and flush toilets is not considered appropriate for children until they are three to four years old. Based on these initial findings, a micro-trial was conducted to assess the feasibility and acceptability of promoting greater use of potties and associated practices. The results of the trial were very encouraging and provided valuable information for the design of a community-wide intervention. Our findings help explain why the emphasis given in most sanitation projects, where efforts have been concentrated on the promotion of latrines, has failed to induce their utilization by small children. Sanitation projects should incorporate interventions that will promote hygienic defecation and stool clearance practices for infants and small children.

Etiologic agents in acute vs persistent diarrhea in children under three years of age in peri-urban Lima, Perú.

In a longitudinal study of acute and persistent diarrhea in 677 children less than three years old in a peri-urban community of Lima, Perú, during 27 months of surveillance, stools were cultured at the beginning of each diarrheal episode and on each subsequent week of illness. Analyzing stool cultures only from children who had not received antibiotic treatment in the 48 h prior to the culture, no association was found between any enteropathogen and persistent diarrhea. We did not find any increase in mixed infections in persistent diarrhea episodes as compared with acute diarrhea, controlling for age, season and anthropometric status. The isolation rate for any given enteropathogen was similar during the first, second, third or later week of illness, but when the presence of a specific enteropathogen was sought in sequential stools within a single episode, no evidence of persistent infection was found. This study shows that in developing countries with a high incidence of diarrheal diseases frequent re-infections with enteropathogens prevalent in the population are one reason for prolonged illnesses. Host factors that increase susceptibility to infection or decrease recovery from illness may also play a role. Further studies of these factors, such as micronutrient deficiencies, are needed to identify a public health intervention to control persistent diarrhea, a condition associated with mortality in many developing countries.

Feeding during acute diarrhea as a risk factor for persistent diarrhea.

Dietary intake during diarrhea in children less than three years of age was estimated from information recorded on illustrated dietary forms used by children's caretakers during the first week of illness in a prospective community-based study of diarrheal diseases in Lima, Peru. The frequency of consumption and the amount consumed of food groups and selected commonly consumed foods were analyzed by the final duration of the diarrheal episode. Cereals were less frequently consumed during the acute phase of diarrheal episodes that ultimately became persistent (> 14 days' duration), apparently shortening the duration of the episode by one day (median duration of four days in children not consuming vs three days in children consuming cereals during diarrhea, p < 0.02 Kaplan-Meier log-rank test). Only roots and tubers (mainly potatoes) were consumed in greater quantity during episodes that became persistent. There was no evidence that consumption of breast milk or non-maternal milk was associated with an alteration in diarrheal duration. This study provides further evidence of the beneficial effects of continuing feeding during diarrhea using foods available at the home level, especially cereals, which are commonly used in the diet of young children.

Genetic diversity of locus of enterocyte effacement genes of enteropathogenic Escherichia coli isolated from Peruvian children.

The aim of this study was to determine the frequency and allele associations of locus of enterocyte effacement encoded esp and tir genes among 181 enteropathogenic Escherichia coli (EPEC) strains (90 diarrhoea-associated and 91 controls) isolated from Peruvian children under 18 months of age. We analysed espA, espB, espD and tir alleles by PCR-RFLP. EPEC strains were isolated with higher frequency from healthy controls (91/424, 21.7%) than from diarrhoeal samples (90/936, 9.6%) (P<0.001); 28.9% of diarrhoeal and 17.6% of control samples were typical EPEC (tEPEC). The distribution of espA alleles (alpha, beta, beta2 and gamma) and espD alleles (alpha, beta, gamma and a new variant, espD-N1) between tEPEC and atypical EPEC (aEPEC) was significantly different (P<0.05). espD-alpha was more common among acute episodes (P<0.05). espB typing resulted in five alleles (alpha, beta, gamma and two new sub-alleles, espB-alpha2 and espB-alpha3), while tir-beta and tir-gamma2 were the most common intimin receptor subtypes. Seventy-two combinations of espA, espB, espD and tir alleles were found; the most prevalent combination was espA-beta, espB-beta, espD-beta, tir-beta (34/181 strains), which was more frequent among tEPEC strains (P<0.05). Our findings indicate that there is a high degree of heterogeneity among EPEC strains isolated from Peruvian children and that aEPEC and tEPEC variants cluster.

A community randomised controlled trial evaluating a home-based environmental intervention package of improved stoves, solar water disinfection and kitchen sinks in rural Peru: rationale, trial design and baseline findings.

INTRODUCTION: Pneumonia and diarrhoea are leading causes of death in children. There is a need to develop effective interventions. OBJECTIVE: We present the design and baseline findings of a community-randomised controlled trial in rural Peru to evaluate the health impact of an Integrated Home-based Intervention Package in children aged 6 to 35 months. METHODS: We randomised 51 communities. The intervention was developed through a community-participatory approach prior to the trial. They comprised the construction of improved stoves and kitchen sinks, the promotion of hand washing, and solar drinking water disinfection (SODIS). To reduce the potential impact of non-blinding bias, a psychomotor stimulation intervention was implemented in the control arm. The baseline survey included anthropometric and socio-economic characteristics. In a sub-sample we determined the level of faecal contamination of drinking water, hands and kitchen utensils and the prevalence of diarrhoegenic Escherichia coli in stool specimen. RESULTS: We enrolled 534 children. At baseline all households used open fires and 77% had access to piped water supplies. E. coli was found in drinking water in 68% and 64% of the intervention and control households. Diarrhoegenic E. coli strains were isolated from 45/139 stool samples. The proportion of stunted children was 54%. CONCLUSIONS: Randomization resulted in comparable study arms. Recently, several critical reviews raised major concerns on the reliability of open health intervention trials, because of uncertain sustainability and non-blinding bias. In this regard, the presented trial featuring objective outcome measures, a simultaneous intervention in the control communities and a 12-month follow up period will provide valuable evidence.