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Biomedical subjects

R E Black

Publications and source records attributed to R E Black.

At least 19 recordsLinked to original sources

Meta-analysis of intervention trials on case-management of pneumonia in community settings.

To appraise the effectiveness of the pneumonia case-management strategy in improving child survival, we have done a meta-analysis of six published intervention trials. The results of a seventh published study and two unpublished studies were also reviewed. The six published studies satisfied our criteria for methodological soundness. The reduction in mortality rate (control group minus intervention group) was estimated for each study, and for all the studies together. For total infant mortality, the overall reduction was 15.9 (95% confidence interval 10.6-21.1) deaths per 1000 livebirths; infant mortality due to acute lower respiratory infection was reduced by 10.7 (4.8-16.7) deaths/1000 livebirths. Mortality among children under 5 years was decreased by 36 deaths/1000 livebirths. The pooled estimates of relative risk are consistent with a 20% reduction in infant mortality and a 25% reduction in under-5 mortality. There was no clear association across the studies between the effect of the pneumonia case-management and extent of co-interventions such as immunisation and oral rehydration therapy. The consistency of findings of all the studies, despite differences in design and methods, shows that the case-management strategy has a substantial effect on infant and under-5 mortality, at least in settings with infant mortality rates of 90/1000 livebirths or more. It is important to find out the most efficient ways of implementing this strategy and integrating it into primary health care.

Child, Preschool

Growth patterns of breast-fed infants in affluent (United States) and poor (Peru) communities: implications for timing of complementary feeding.

We compared growth, dietary intake, and morbidity of infants breast-fed for > or = 12 mo from two populations: Davis, CA (n = 46) and Huascar, Peru (n = 52). When compared against WHO reference data (based primarily on formula-fed infants), Huascar infants appeared to falter as early as 3-4 mo, but when compared with Davis breast-fed infants, the curves for weight and length were very similar in girls until 10-12 mo and in boys until 6-9 mo. Thereafter, Huascar infants grew less rapidly than did Davis infants. Breast milk intake was very similar between groups, but in Huascar the amount and nutrient density of complementary foods consumed after 6 mo were lower and morbidity rates were much higher than in Davis. These results indicate that growth faltering of Huascar infants, when judged against breast-fed infants in the United States, occurs primarily after the first 6 mo of life and is not due to poor lactation performance.

Animals

Enteropathogens associated with acute and persistent diarrhea in Bangladeshi children less than 5 years of age.

A longitudinal study of diarrhea was carried out from May 1988 to April 1989 by household surveillance of 705 children less than 5 years old in rural Bangladesh. Stool samples were examined for enteric pathogens at the beginning of each diarrheal episode. For persistent episodes, stool examination was repeated on days 15-17 of the illness. For each case of persistent diarrhea, stool samples from age-matched acute diarrheal and healthy controls were examined. Compared with healthy controls, cases of diarrhea were associated with Shigella species (P = .07) and rotavirus (P less than .05). Diffusely adherent Escherichia coli (P less than .05) and cryptosporidia (P = .07) were the only enteropathogens associated with persistent diarrhea in comparison with acute diarrhea. No more than 15% of children had the same class of pathogen identified from stool on both days 1-3 and days 15-17, indicating that persistent infection was uncommon. However, a different enteropathogen was frequently found on days 15-17, suggesting that sequential infection may be a cause of persistent diarrhea.

Bangladesh

Epidemiological and clinical characteristics of acute and persistent diarrhoea in rural Bangladeshi children.

A community-based longitudinal study of acute and persistent diarrhoea in 705 children less than five years old was carried out for a year in a rural area of Bangladesh. Diarrhoea morbidity data were collected from each study child every fourth day by home visit. Clinical features of diarrhoeal episodes and diarrhoeal management information were documented. The overall diarrhoeal incidence rate in the study children was 4.6 episodes per child per year. The incidence of persistent diarrhoea was 34/100 child-years. Persistent diarrhoea was positively associated with young age and more severe illness, characterized by the presence of clinical dehydration or blood in the stool in the first week. Use of ORT in the first week was positively associated and use of an antibiotic was negatively associated with the occurrence of persistent diarrhoea. Reduced breast-feeding and consumption of cow's milk at some time during the episode were also positively associated with persistence. This would suggest that appropriate fluid and dietary management for all episodes should be the goal. Children with more severe initial illness characterized by the presence of blood in the stool or clinical dehydration should have more careful follow-up to identify persistent episodes and adverse nutritional effects. Breastfeeding should be continued during acute diarrhoea, but the role of ORT, antibiotics and cow's milk deserves further investigation.

Acute Disease

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.

Acute Disease

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.

Acute Disease

Escherichia coli associated with acute measles and diarrhoea at Kenyatta National Hospital, Kenya.

Three hundred and three children under 5 years old with acute measles and diarrhoea (cases) and 300 other age-matched children with diarrhoea (controls) were examined for enteroadherent E. coli (EAEC) and other agents including rotavirus and Cryptosporidium. EAEC was determined by tissue culture of HEP-2 cells. Other agents were determined by conventional methods. EAEC was identified from both cases and control accounting for 10.3% (31/303) and 15.2% (46/300) respectively. Other bacterial agents were: 10.3% (31/303) from cases and 12.8% (39/300) from controls. A higher detection rate of enteroparasites was found among cases 15% (45/300) than controls 8.9% (27/300) whereas rotavirus was the reverse, 3% (9/303) in cases and 30.3% (92/300) in controls. To our knowledge characterization of EAEC has not been done before and therefore might be attributing factor to some of our unexplained diarrhoeal cases.

Child, Preschool

Lack of therapeutic efficacy of vitamin A for non-cholera, watery diarrhoea in Bangladeshi children.

Vitamin A deficiency has been postulated to increase childhood mortality, possibly through increasing the severity and case-fatality of infectious diseases like diarrhoea. A clinical trial was conducted to measure the effect of vitamin A therapy on the severity and duration of acute episodes of non-cholera, watery diarrhoea; 83 children with less than 48 h of illness were randomized to receive vitamin A (200,000 IU of retinyl palmitate) orally or placebo during hospitalization at the International Centre for Diarrhoeal Disease Research in Bangladesh. The patients were similar initially with regard to age, nutritional status and severity of diarrhoea prior to admission. No adverse effects of vitamin A were detected. During hospitalization there were no differences between groups in duration of illness or stool output. Thus, vitamin A can be given safely during diarrhoeal illness to augment hepatic reserves and possibly provide a beneficial effect in regard to subsequent episodes of diarrhoea and other infections, but this supplementation should not be expected to have a therapeutic effect on a current episode.

Bangladesh

Relative effects of diarrhea, fever, and dietary energy intake on weight gain in rural Bangladeshi children.

Quantitative studies of morbidity, food intake, and somatic growth were done prospectively during 14 mo for 70 children aged 5-18 mo in two Bangladeshi villages. When random-effect regression models were used, monthly changes in weight were inversely related to proportions of days in the month with fever and diarrhea and positively related to energy intake per kilogram body weight. Interestingly, weight changes did not vary with age in this interval. Estimates indicate that increasing energy intakes to the recommended World Health Organization level would have a significantly greater effect on weight gain than would the elimination of diarrhea and fever. With energy at recommended intake and diarrhea and fever prevalence as found in US children, weight gain is predicted to be near that of the international reference population. Therefore, interventions aimed at improving dietary intake may be as important as infection-control programs for improving growth of children in poor developing nations.

Bangladesh

Validation of the diagnosis of childhood morbidity using maternal health interviews.

The diagnosis of childhood illness by maternal health interview surveys is widely used to estimate the prevalence of childhood morbidity in developing countries. To determine the validity of interview-based diagnoses, and to define simple, sensitive and specific diagnostic algorithms, we compared symptoms and signs reported by mothers during structured interviews with physicians' diagnoses for 271 children on the Philippine island of Cebu. The 271 children had 318 physician diagnosed illnesses: 105 acute lower respiratory infections (ALRI), 121 diarrhoeas, 36 measles, 50 upper respiratory infections (URTI), 5 roseola infantums and one milaria rubria. An algorithm for measles (age greater than or equal to 120 days, rash and fever greater than or equal to 3 days and fading of rash) had a sensitivity and specificity of 94%. For ALRI an algorithm of cough, dysponea and fever had a sensitivity of 82%, but specificity was lower in comparison with URTI (58%) than with children who had no respiratory illness (79%). Inclusion of signs of respiratory distress (flaring of nostrils, intercostal retraction) raised the specificity to 83-84%, but reduced sensitivity to 68%. Diagnosis of diarrhoea based on frequent loose or liquid stools had a sensitivity of 95-97% and specificity of 80% in children with or without concomitant non-diarrhoeal illnesses. Addition of questions on numbers of stools (greater than or equal to 6 per day), and no signs of dehydration increased specificity to 95% but reduced the sensitivity to 84-86%. However, specific signs of dehydration were not well reported by the mothers.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms

Methodological issues in diarrhoeal diseases epidemiology: definition of diarrhoeal episodes.

A review of the diarrhoeal disease literature reveals considerable variability in the definition of diarrhoeal episodes. The use of various definitions of diarrhoea and episodes leads to misclassification, affects the estimates of the disease burden in communities and reduces comparability of the findings from different studies. This study is an attempt to validate the definition of diarrhoeal episodes using prospectively collected community-based surveillance data. In comparative validation analyses, three or more loose stools or any number of loose stools containing blood in a 24-hour period seemed to be the best definition of diarrhoea. Three intervening diarrhoea-free days seemed to be the optimum to define a new episode. The implications of using differing definitions and the importance of using a validated definition are discussed.

Bangladesh

Accuracy and completeness of mothers' recall of diarrhoea occurrence in pre-school children in demographic and health surveys.

In the context of the Demographic and Health Surveys program (DHS), data were collected on diarrhoeal diseases in childhood and related treatment patterns. In this paper we assess the accuracy and completeness of mothers' recall of diarrhoea in 19 national DHS surveys and discuss the implications for health interview surveys in developing countries. It is concluded that there is under-reporting of diarrhoea if the recall period is longer than 2-3 days, whereas there may be over-reporting of very recent or current diarrhoea in most DHS surveys. Reporting errors appear to vary considerably between countries, which affects the comparability of survey results. A second and related issue, that is addressed in this paper, is the reporting of treatment practices by duration of diarrhoeal episode. There were no major differences in reported treatment patterns between children with diarrhoea that terminated in the last two weeks and children with current diarrhoea of at least two days' duration. The implications of the findings for retrospective surveys on childhood morbidity and treatment patterns are discussed.

Child, Preschool

Epidemiologic, clinical, and laboratory characteristics of acute vs. persistent diarrhea in periurban Lima, Peru.

Longitudinal studies of acute and persistent diarrhea in 677 children less than 3 years old were conducted for 27 months in an underprivileged, periurban community near Lima, Peru. Incidence rates and accurate durations of diarrhea were obtained by twice-weekly community-based surveillance and clinical and laboratory features of diarrheal episodes were documented. Study children had an overall incidence of diarrhea of 8.1 episodes per child-year and an incidence of persistent (greater than 14 days) diarrhea of 0.25 episodes per child-year. Episodes of longer duration were associated with young age (0-5 months) and more severe illness (greater than or equal to 6 diarrheal stools per day) in the first week. None of the laboratory tests performed in the first week of illness (fecal leukocytes, blood, reducing substances, pH, or fat) proved of value to identify episodes that would become persistent. Although steatorrhea was commonly present in the acute phase of the illness, it became less frequent by the third or subsequent week of illness in the persistent diarrheas. These results suggest that there are no clinical or laboratory features of acute diarrhea that are strongly predictive of the subset of diarrheas that persist. Thus, it is important that all diarrheal episodes should have appropriate fluid and dietary management and follow-up to detect the persistent diarrheas that may need special intervention.

Acute Disease

Would control of childhood infectious diseases reduce malnutrition?

Infectious diseases and especially diarrheal diseases have been noted to have an adverse effect on the growth of underprivileged children in developing countries. Diarrheal diseases have been estimated to account for 10-80% of growth retardation in the first few years of life, with the magnitude of effect possibly modified by other factors, such as the adequacy and source of dietary intake, treatment and feeding practices during and following illness and the opportunity for catch-up growth after illness. In the only study in which infectious diseases and routine dietary intake have been evaluated simultaneously, inadequate dietary intake rather than infectious diseases, was found to have the predominant role in growth faltering. Although reduction in infectious diseases is desirable for many reasons, the relative feasibility and cost of this approach to improve nutritional status must be compared with more direct nutrition interventions.

Child

Transmission factors and socioeconomic status as determinants of diarrhoeal incidence in Lima, Peru.

As part of a longitudinal, community-based study of diarrhoeal morbidity in a peri-urban community in Lima, Peru, a household survey was administered to ascertain possible risk factors, based on transmission routes, for diarrhoeal incidence. Socioeconomic information was also obtained in the survey and a composite socioeconomic status (SES) indicator was created based on four variables: income (wealth), ownership of 4 functioning electrical household appliances, community participation, and house construction. Both transmission factors and the SES indicator were analysed for their effects on diarrhoeal incidence using both bivariate and multivariate methods. The SES indicator, method of water storage, if the child was seen eating faeces or soil were all significantly associated with diarrhoeal incidence. In a final logistic model, water storage, location of defecation for children, child eating soil or faeces, and age, demonstrated significant results. Children in households with water stored in containers without a faucet were twice as likely to have a high incidence of diarrhoea (greater than 7 episodes/child/year). The SES indicator was not significant in the logistic model, but high SES was associated with whether or not the child was reported as having been seen eating faeces or soil and with non-use of latrines by adults. Also low SES households were more likely to have better water storage methods. Therefore, it would seem that (SES) does not independently determine diarrhoeal incidence, but rather may be functioning through these transmission factors to affect diarrhoeal incidence.

Child, Preschool

Do child feeding practices change due to diarrhoea in the Central Peruvian Highlands?

This study assessed feeding practices in relation to diarrhoea among 2,599 children, aged 0-3 years, in the highlands of central Peru. A high prevalence of diarrhoea was observed, with 18% of the children ill with diarrhoea the preceding day. With few exceptions, the presence of diarrhoea did not alter the types of foods actually offered to young children. Caretakers, however, reported that children with diarrhoea should be given different foods. Appetite for breastmilk was reported by mothers to remain normal for children with diarrhoea; however, appetite for nonhuman milk and solid food was reported to decrease substantially. Since data on amounts of food consumed were not collected, whether the total nutrient intake was reduced due to decreases in amounts of food consumed can not be determined from this study. The major findings are that although mothers report reducing the types of foods offered to their sick infants, in actuality the types of foods offered vary little during illness. However, because mothers are quite concerned about the lack of appetite among young children, they may be particularly amenable to changing feeding practices following diarrhoea episodes. The promotion of improved complementary foods and feeding practices during and after diarrhoea may be an ideal method by which to improve weaning practices in Peru.

Appetite

Association between the acquired immunodeficiency syndrome and infection with Salmonella typhi or Salmonella paratyphi in an endemic typhoid area.

Eight cases of typhoid and paratyphoid fever were identified during a 4-year period in a cohort of 117 patients who were positive for human immunodeficiency virus in Lima, Peru. Asymptomatic patients with human immunodeficiency virus infection and patients with the lymphadenopathy syndrome had a typical clinical presentation and response to therapy. Patients with the acquired immunodeficiency syndrome who were culture positive for Salmonella typhi or Salmonella paratyphi presented with fulminant diarrhea and/or colitis; the two patients for whom at least 2 months of follow-up were available relapsed. In our cohort there were 0.06 cases of typhoid or paratyphoid per patient year of observation; this rate is approximately 60 times that in the general population in Lima, and 25 times that in the 15- to 35-year-old age group. Our data indicate that patients who are positive for human immunodeficiency virus are at significantly increased risk for infection with S typhi and S paratyphi, and suggest that the clinical presentation of these diseases in patients with the acquired immunodeficiency syndrome differs from that seen immunocompetent hosts.

Acquired Immunodeficiency Syndrome