Persistent diarrhoea in a rural area of Bangladesh: a community-based longitudinal study

Consequences of Shigella infection in young children: a systematic review

OBJECTIVES

We conducted a systematic review of the longitudinal consequences of Shigella infection in children to inform the value proposition for an effective vaccine.

METHODS

We searched PubMed and Embase for studies published from January 01, 1980 to December 12, 2022 and conducted in low- and middle-income countries that included longitudinal follow-up after Shigella detection among children aged <5 years, irrespective of language. We collected data on all outcomes subsequent to Shigella detection, except mortality.

RESULTS

Of 2627 papers identified, 52 met inclusion criteria. The median sample size of children aged <5 years was 66 (range 5-2172). Data were collected in 20 countries; 56% (n = 29) of the publications included Bangladesh. The most common outcomes related to diarrhea (n = 20), linear growth (n = 14), and the mean total cost of a Shigella episode (n = 4; range: $ 6.22-31.10). Among children with Shigella diarrhea, 2.9-61.1% developed persistent diarrhea (≥14 days); the persistence was significantly more likely among children who were malnourished, had bloody stool, or had multidrug-resistant Shigella. Cumulative Shigella infections over the first 2 years of life contributed to the greatest loss in length-for-age z-score.

CONCLUSION

We identified evidence that Shigella is associated with persistent diarrhea, linear growth faltering, and economic impact to the family.

The variability of childhood diarrhea in Karachi, Pakistan, 2002-2006

Diarrhea burden is often estimated using cross-sectional surveys. We measured variability in diarrhea prevalence among children < 5 years of age living in squatter settlements in central Karachi, Pakistan. We pooled data from non-intervention control households from studies conducted from 2002 through 2006. The prevalence of diarrhea varied on average by 29% from one week to the next, by 37% from one month to the next, and during peak diarrhea season by 32% from one year to the next. During 24 months when the same nine neighborhoods were under surveillance, each month the prevalence of diarrhea varied by at least an order of magnitude from the lowest to the highest prevalence neighborhood, and each neighborhood recorded the highest diarrhea prevalence during at least one month. Cross-sectional surveys are unreliable measures of diarrhea prevalence.

Systematic review of birth cohort studies in South East Asia and Eastern Mediterranean regions

BACKGROUND

Few longitudinal studies of children have taken place in the developing world, despite child mortality being concentrated there. This review summarises the methodologies and main outcomes of longitudinal studies of pre-school children (0 to 59 months) in the World Health Organization's South East Asia (SEA) and Eastern Mediterranean (EM) Regions.

METHODS

A systematic search of literature using pre-defined criteria revealed 7863 papers. After application of quality criteria, 120 studies were selected for analysis.

RESULTS

The search revealed 83 studies in the SEA region and 37 in the EM region, of which 92 were community-based and 8 facility-based. Objectives were diverse but topics included growth (n = 49 studies), mortality (n = 28), nutrition (n = 24), and infectious diseases (n = 33). Only 12 studies focused on non-communicable diseases. Duration ranged from 7 to 384 months. Measurements included anthropometric (n = 56 studies), socioeconomic (n = 50) and biological sampling (n = 25), but only one study was DNA-based.

CONCLUSION

Biobanks have emerged as the most successful approach to generating knowledge about disease causes and mechanisms. Little of this is possible to undertake in the in SEA or EM regions, however. Further longitudinal studies of young children with DNA sampling should be set up to better understand determinants of diseases in low-income countries.

Risk factors for childhood diarrhea incidence: dynamic analysis of a longitudinal study

BACKGROUND

Several longitudinal studies have investigated factors associated with childhood diarrhea in developing countries. However, most studies have neglected important dynamic features of the longitudinal design and hierarchical interrelationships among the potential risk factors.

METHODS

We conducted a longitudinal study of 902 children, age 0 to 36 months at baseline, in a large urban center in northeastern Brazil. Diarrhea data were collected by following children from October 2000 until January 2002 with biweekly home visits. We used a dynamic time-to-event analysis to account for several longitudinal features. We applied an effect-decomposition strategy to quantify direct and indirect effects of risk factors grouped in different blocks.

RESULTS

Child's age and an autoregressive effect of past diarrhea episodes explained some of the decline of diarrhea incidence observed throughout the study (from more than 14 episodes to 2 episodes per child-year), a phenomenon already observed but not explained in other longitudinal diarrhea studies. We identified the following major diarrhea determinants: low socioeconomic status, poor sanitation conditions, presence of intestinal parasites, and absence of prenatal examination. The effect of socioeconomic status was mediated mostly by living and sanitation conditions.

CONCLUSION

Our study shows important advantages of applying a dynamic analysis approach to longitudinal observational studies of diarrhea or other acute diseases and highlights the complex interrelationships of diarrhea determinants. Our results confirm the importance of sanitation as a major determinant of child health in urban settings of developing countries.

Childhood diarrhoea symptoms, management and duration: observations from a longitudinal community study

This study examined the evolution and duration of diarrhoea episodes observed in a community setting, with regard to symptoms and carers' responses. The study group comprised 1156 children, aged 0-36 months, who were followed-up with twice-weekly home visits in 30 sampling areas in the city of Salvador, northeast Brazil. A total of 2403 diarrhoea episodes (mean duration: 2.9 days) were recorded. The number of soft/liquid motions per day (3.6) did not vary significantly with duration, but other symptoms were more commonly reported in the longer episodes. However, when the data were analysed by day of the episode, rather than the episode's overall duration, the reported frequency of fever and vomiting declined significantly with time. During the course of an episode, rehydration, medication and care-seeking also showed a decline in frequency after the first or second week. As episodes continue, less rehydration and medical care are provided by carers, whereas they ought to be maintained because of the continued purging and cumulative effect of the symptoms. Since most cases of diarrhoea are managed at home, it is important to understand how to encourage better management of the longer episodes, which cause an increasing proportion of mortality in some countries.

A prospective study of diarrhea and HIV-1 infection among 429 Zairian infants

BACKGROUND

Persistent diarrhea is a prominent feature of the acquired immunodeficiency syndrome in adults, but its cause and its effect on children with human immunodeficiency virus (HIV) infection are largely unknown, particularly in Africa.

METHODS

We studied a birth cohort of 429 infants born to HIV-positive or HIV-negative mothers in Zaire to determine the incidence of acute, recurrent (> or = 2 episodes), and persistent (> or = 14 days) diarrhea; outcome; and risk factors.

RESULTS

Of the 238 infants whose mothers were HIV-positive, 53 were infected, 139 were uninfected, and the HIV status of 46 could not be determined. As compared with uninfected infants, infected infants had higher incidence rates for acute diarrhea (170 vs. 100 episodes per 100 child-years, P = 0.003), recurrent diarrhea (21 vs. 11, P = 0.12), and persistent diarrhea (19 vs. 4, P < 0.003). Persistent diarrhea developed in 11 HIV-infected infants; all but 1 died. It also developed in 19 uninfected infants; all but 1 survived. The prevalence of stool pathogens was similar in the two groups. In a multivariate model, persistent diarrhea in an infant was independently associated with symptomatic HIV type 1 infection in the mother (relative hazard, 1.5; P = 0.08). The incidence of persistent diarrhea in the uninfected infants of seropositive mothers was nearly double that in the uninfected infants of seronegative mothers (4.9 vs. 2.7 episodes per 100 child-years), and the risk increased if the mother died (relative hazard, 10.4). Significant growth impairment and severe immunosuppression occurred in the six to eight weeks before the onset of persistent diarrhea.

CONCLUSIONS

In Zaire, infants with HIV infection have an 11-fold increased risk of death from diarrhea, largely persistent diarrhea, which is often preceded by recurrent episodes of acute diarrhea, malnutrition, or immunosuppression. Illness and death of the mother increase that risk, even among her uninfected infants.

Early child health in Lahore, Pakistan: I. Study design

In this paper, details are given of a community based follow up study of four areas: a village, a periurban slum, an urban slum and an upper middle class control group living in and around Lahore, Pakistan. The aim was to characterize the determinants of child health in a rapidly urbanizing community. The study was undertaken in two steps. An initial cross-sectional survey collecting socio-economic and demographic background information was carried out between March to August 1984. This was followed by a longitudinal study of 1476 infants representing the outcome of the pregnancies registered continuously between September 1984 to March 1987 among the 3242 families in the study. These infants were followed monthly from birth to 3 years of age and thereafter less frequently. In this communication we describe the study design, the study population, the organization and the research methodology used, including the reasons for drop outs from birth to 24 months of age. The internal consistency of the data is also presented. After the initial examination of the newborns within between 0-7 days of birth, the infants were visited monthly for 24 months making a total of 20911 examinations. At 24 months of age 70% of the infants were still in the study, 11% had died before reaching this age, 13% had moved from the area and 6% had refused to participate in the study. The economic, conditions, social structure, and the quality of life were found, not surprisingly, to vary significantly among the four areas. This community-based project provides new, critical and reliable information for local health planners. The study highlights the importance of the development of a useful model for research collaboration between institutions in developed and developing countries.

Early child health in Lahore, Pakistan: VII. Diarrhoea

This study was carried out to obtain reliable prospective data on the incidence, home management and duration of infantile diarrhoeal disease in a developing and rapidly urbanizing community. Fourteen hundred and seventy six infants from 4 different communities of Lahore, representing different stages of urbanization, were followed prospectively from birth to 2 years of age. Each child had an average of 3.6 episodes of diarrhoea during one year; 4.3 episodes per child per year in the village, 4.4 in the periurban slum, 3.4 in the urban slum and 1.4 in the upper middle (Um) class control group. The maximum incidence of diarrhoeal episodes occurred in children between 9-10 months of age. No sex difference was found. The seasonal variation showed a peak incidence during April-June. Bloody diarrhoea, in 3-5% of the episodes, was predominantly seen in winter months and in older infants. The maximum use of ORS was seen in the Um class (53%). Antibiotics were used in 75% of all diarrhoeal episodes maximally in the Um class, and morphine derivatives in 1% of all cases. The overall incidence of persistent diarrhoea was 14% of all acute cases, being highest in the village (18%), followed by the periurban slum (14%), Um class (10%) and urban slum (8%) with peak incidence occurring in June and July. Our results confirm the magnitude of the problem of diarrhoea.(ABSTRACT TRUNCATED AT 250 WORDS)

Early child health in Lahore, Pakistan: V. Feeding patterns

The feeding practices of children (n = 1476) from birth to 24 months, as determined in a longitudinal study, in Lahore, Pakistan, are presented. Four socioeconomic groups at various levels of urbanization were included; a village, periurban slum, urban slum and an upper middle class. Initiation of breastfeeding was delayed in all the neonates. Sixty-five percent of the periurban slum mothers and 45% of the village mothers had not started breastfeeding at 48 hours after the birth of the infant. Prelacteal feedings, especially of herb water and honey, were the norm. Breastfeeding was highly prevalent. Eighty-seven to 98% of the infants in all the areas were breastfed at one month of age. Exclusive breastfeeding was rare, with 9% at one month, declining rapidly with age and being highly influenced by season. Partial breastfeeding was the most common mode of feeding. Water in addition to human milk was given by 45-73% of the mothers living in the urban slum, village and periurban slum at one month of age. Fresh animal milk and/or commercial formula was already being given at 1 month by 22-64% of the mothers in all areas. Commercial formula was the preferred food in the upper middle class, while in the other three areas it was rare and fresh animal milk was mainly used. More than 50% of the mothers in the village and in the periurban slum gave diluted animal milk even beyond the age of 10-15 months. In the upper middle class 50% of the infants were fed semisolids at the age of four months, while in the village, the periurban and the urban slum at 6 months of age only 10%, 12% and 47% of the infants received semisolids. The results of this study indicate that breastfeeding was highly prevalent in the three poorest areas. However, in all the areas initiation of breastfeeding was delayed and prelacteal feeding was the norm. Exclusive breastfeeding was rare, feeding bottles were used by 82-100% of the mothers to feed supplements and human milk substitutes, in the four areas.

Epidemiology of diarrhoeal disease: implications for control by vaccines

Vaccines present perhaps the most attractive solution to the worldwide problem of diarrhoeal disease. Epidemiological evidence has important implications for the development and use of such vaccines, and results of studies on diarrhoeal diseases in developing and developed countries, in particular among children, and travellers' diarrhoea are reviewed. The virulence and pathogenicity of various enteropathogens are discussed, and the extent to which immunity may be acquired. It is concluded that the development of appropriate vaccines may be a complex task.

Seasonal variation of paediatric diseases in The Gambia, west Africa

In a 3-year prospective study of 9584 consecutive paediatric admissions to the Royal Victoria Hospital in Banjul, The Gambia, we examined the impact of seasonal variations in childhood diseases. The four principal diseases (falciparum malaria, pneumonia, gastro-enteritis and malnutrition) all peaked in September to October following the rainy season. The mortality rate was also higher in the rainy season than in the dry season. Of the 1525 children with cerebral malaria, 83% were admitted during the extended rainy season from July to December. With the emergence of chloroquine-resistant malaria over the 3 years, there was a 27% annual increase in severe anaemia owing to malaria. The median age of malarial anaemia (23 months) was significantly younger than that of cerebral malaria (42 months). Malnutrition peaked immediately following the annual rainy season epidemics of bacterial gastro-enteritis but was not associated with the cool dry season rotavirus outbreaks. Rainy season diarrhoea was also associated with more persistent diarrhoea, an older mean age and a higher mortality. Meningitis was caused by either pneumococcus or Haemophilus influenzae in 64% of cases, of whom 19% were 0-2 months of age. Causes of death in hospital showed good agreement with Gambian community studies. We conclude that analysis of hospital data in a developing country can give accurate information on childhood morbidity and mortality patterns which can be used to set priorities for health care interventions. Seasonal variation is a cardinal feature of paediatric diseases in this part of Africa, and accentuates the vulnerability of children in poor families.

Deaths due to dysentery, acute and persistent diarrhoea among Brazilian infants

In a population-based study, all infant deaths occurring in a one-year period in the metropolitan areas of Porto Alegre and Pelotas, in southern Brazil, were studied. There were 227 infants who presented diarrhoea during the fatal illness, and in 75% of these diarrhoea was considered to be the underlying cause of death. Acute diarrhoea (< 14 days' duration) accounted for 28% of the deaths, persistent diarrhoea for 62% and dysentery for a further 10%. Approximately one-half of the children with persistent diarrhoea were admitted to a hospital in the first two weeks of the episode. Hospital-acquired infections were likely to have contributed to one- to two-thirds of deaths due to dysentery and persistent diarrhoea. A comparison with neighbourhood controls showed that breast milk provided substantial protection against deaths due to either acute or persistent diarrhoea.

Epidemiology of persistent diarrhea and etiologic agents in Mirzapur, Bangladesh

To determine the epidemiology and etiologic agents of persistent diarrhea we carried out an intensive diarrhea surveillance on children less than six years old in rural Bangladesh. From March 1987 to February 1989 we examined 363 children through diarrhea recall interviews and analyzed stool samples of all diarrhea cases for potential pathogens. Results showed that children had an average of two episodes per year and the incidence rate of diarrheal episodes defined as acute (< 14 d) and persistent (> or = 14 d) varied similarly with age. The peak incidence (episodes/child/year) of acute diarrhea (2.8) and persistent diarrhea (0.8) occurred in the 6-11 months age group. The data showed that an episode tended to be prolonged if the stool was loose/mucoid or bloody at onset. Aggregative adherent Escherichia coli was found significantly more often at onset in persistent than in acute episodes, whereas Shigella, Aeromonas, Giardia and toxigenic E. coli were isolated with less frequency in persistent than acute episodes. This suggests that other factors might be more important in the development of persistent diarrhea than specific pathogens.

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.

Reduction in diarrhoeal diseases in children in rural Bangladesh by environmental and behavioural modifications

The impact of a water, sanitation and hygiene education intervention project on diarrhoeal morbidity in children under 5 years old was evaluated in a rural area of Bangladesh. Data were collected throughout 1984-1987, covering both pre- and post-intervention periods, from an intervention and a control area. The 2 areas were similar with respect to most socio-economic characteristics and baseline levels of diarrhoeal morbidity. The project showed a striking impact on the incidence of all cases of diarrhoea, including dysentery and persistent diarrhoea. By the end of the study period, children in the intervention area were experiencing 25% fewer episodes of diarrhoea than those in the control area. This impact was evident throughout the year, but particularly in the monsoon season, and in all age groups except those less than 6 months old. Within the intervention area, children from households living closer to handpumps or where better sanitation habits were practised experienced lower rates of diarrhoea. These results suggest that an integrated approach to environmental interventions can have a significant impact on diarrhoeal morbidity.