Malnutrition is associated with increased diarrhoea incidence and duration among children in an urban Brazilian slum.

This study was undertaken to further define the relationship between malnutrition and subsequent diarrhoeal illness among children. A cohort of 61 children under five years of age was followed for two years in an urban Brazilian slum. Nutritional status was determined at two-month intervals and was used to predict the subsequent occurrence of diarrhoea. A significant, graded association between worsened nutritional status, as measured by length- or weight-for-age, and diarrhoea incidence was found. This relationship was present for both two-month and one-year periods following nutritional assessment. The average duration of diarrhoea was also significantly longer during the two-month periods which were preceded by the worst nutritional status. Overall, the most malnourished children had nearly twice the total number of days of diarrhoea that better nourished children had. These results provide additional evidence that a significant association between malnutrition and both increased diarrhoea incidence and duration exists.

Diarrhea as a cause and an effect of malnutrition: diarrhea prevents catch-up growth and malnutrition increases diarrhea frequency and duration.

Diarrhea and malnutrition, alone or together, constitute major causes of morbidity and mortality among children throughout the tropical world. Data from northeast Brazil, taken with numerous other studies, clearly show that diarrhea is both a cause and an effect of malnutrition. Diarrheal illnesses impair weight as well as height gains, with the greatest effects being seen with recurrent illnesses, which reduce the critical catch-up growth that otherwise occurs after diarrheal illnesses or severe malnutrition. Malnutrition (whether assessed by impaired weight or height for age) leads to increased frequencies and durations of diarrheal illnesses, with a 37% increase in frequency and a 73% increase in duration accounting for a doubling of the diarrhea burden (days of diarrhea) in malnourished children. A multi-pronged approach focusing on those with prolonged diarrhea and severe malnutrition is suggested.

Seroepidemiologic study of Cryptosporidium infection in children from rural communities of Anhui, China and Fortaleza, Brazil.

A cluster-sampling, cross-sectional study was conducted for assessing the prevalence of Cryptosporidium infection in children less than 16 years of age from three villages, Dondian, Linshan, and Fuziyin, in rural Anhui in eastern China. Among 320 apparently healthy children less than 10 years of age from Dondian who had stool specimens collected, cryptosporidial oocysts were found in stools of three children from Dondian, and no positive specimens were found in 239 children studied from Linshan. In addition, a total of 610 serum samples from children in these three villages were tested for specific IgG antibody to Cryptosporidium with an enzyme-linked immunosorbent assay (ELISA) and the prevalence rates were 42.3%, 51.7%, and 57.5%, respectively, in Dondian, Linshan, and Fuziyin. Seroprevalence increased progressively with age. No detectable antibody was found in infants between two and six months of age, and seropositivity steadily increased after one year of age. Among 36 sera from adults 15-60 years of age without diarrheal illness in Huanglu villages of rural Chaohu, 50% (18 of 36) were positive. As expected, a good correlation was found in the specific IgG antibody between the paired serum specimens from 30 matched mother-neonates who showed transplacental transfer of IgG. However, little or no IgM antibody was seen in the neonates even though several mothers had a positive anticryptosporidial IgM enzyme-linked immunoassay result. Forty randomly selected serum samples from children less than four years of age in a similarly impoverished semiurban community in Fortaleza, Brazil, where the majority of households also have pit toilets and shared community water supplies and 172 serum samples from patients one month to 29 years of age admitted to the University of Virginia Hospital without diarrhea were also examined. In Fortaleza, almost all children acquired antibody by their second year of life, demonstrating the high prevalence of this infection. In rural Anhui, only about half the children were infected by 5-7 years of age. The overall prevalence rate (16.9%) of seropositivity among children and young adults in Virginia was much lower than in China and Brazil. These results indicate that cryptosporidial infection is ubiquitous, and is highly endemic in these impoverished communities. The difference between China and Brazil may reflect earlier weaning, hygiene practices, poorer water or sanitation, multiple siblings in family and geographic environment in Brazil.

Persistent diarrhea in northeast Brazil: etiologies and interactions with malnutrition.

With the improved control of acute diarrheal illness mortality with oral rehydration therapy, persistent diarrhea is now emerging as a major cause of childhood mortality in tropical developing areas like the impoverished populations in Brazil's Northeast. "Graveyard surveillance" in the rural community of Guaiuba in northeastern Brazil revealed fully half of the 70% diarrhea mortality was due to persistent diarrheal illnesses. Furthermore, 11% of 14 or more diarrheal illnesses per child per year in an urban slum in Fortaleza persisted beyond 14 days, a definition that clearly identified the high risk children for heavy diarrhea burdens. Not only did heavy diarrhea burdens ablate the key "catch-up" growth seen in severely malnourished children and in children following previous diarrheal illnesses, but malnutrition significantly predisposed children to a greater incidence and duration of diarrhea as well as a greater incidence of persistent diarrhea. Etiologic studies of 37 children presenting with persistent diarrhea to Hospital das Clinicas in Fortaleza revealed that Cryptosporidium (in 13%) and enteroadherent E. coli (36% with aggregative, 29% with diffuse and 13% with localized adherence to HEp-2 cells) were the predominant potential pathogens found in the stool or upper small bowel. These findings suggest that persistent diarrhea is emerging as an important health problem in Brazil's Northeast, that it identifies a high risk child for heavy diarrhea burdens, that important interactions occur with malnutrition and that Cryptosporidium and enteroadherent E. coli warrant further study as potential etiologies of this major cause of morbidity and mortality.

Prolonged and recurring diarrhea in the northeast of Brazil: examination of cases from a community-based study.

From prospective daily surveillance of diarrhea in a poor rural area of northeastern Brazil, this study of prolonged diarrheal episodes identified the 3% of diarrheal episodes that lasted 15 days or longer. These episodes also defined a subpopulation of children who spent over 16% of their days with diarrhea. Such children warrant further attention in an attempt to define potentially treatable causes as well as to assure appropriate nutritional support. There was no single season for these prolonged illnesses, but they appeared to involve both the wet, slightly warmer season of peak enterotoxigenic Escherichia coli diarrhea as well as the dry, slightly cooler season of peak rotaviral infections. Limited etiologic data support this idea that multiple pathogens are found, often in combination with each other, that may work together to contribute to the important problem of chronic diarrhea. Future studies should focus attention on further defining risk factors, mechanisms, and appropriate therapy for the subset of children who experience prolonged diarrhea in this type of setting.

A prospective study of persistent diarrhea among children in an urban Brazilian slum. Patterns of occurrence and etiologic agents.

Persistent diarrhea is a major health problem among children in developing areas of the world. Since few community-based studies have addressed the epidemiology or etiology of this condition, we undertook prospective diarrheal surveillance among a cohort of 175 children less than 5 years of age over a 28-month period in an urban slum in northeastern Brazil. Very high diarrhea illness burdens were found. The children in this cohort had an average of 11 episodes per year and spent 82 days per year with diarrhea. A total of 65% of children had at least one episode of persistent diarrhea (greater than or equal to 14 days duration). These episodes accounted for 50% of all days of diarrhea and 11% of all episodes. The occurrence of at least one episode of persistent diarrhea identified all children who spent at least 15% percent of days with diarrhea. Among children with and without diarrhea, rotavirus was the agent isolated most frequently, followed by Giardia lamblia and enterotoxigenic coliforms. The agents isolated from children with acute and persistent diarrhea were similar, which suggests that other factors must be operative in the development of persistent diarrhea.

American visceral leishmaniasis (kala-azar).

Visceral leishmaniasis (kala-azar) is an important cause of morbidity and mortality in widely scattered areas of the world. To better characterize the South American form of the disease, the clinical and laboratory manifestations of 29 patients admitted to hospital (18 male and 11 female patients, mean age 4.9 years), were assessed in an endemic area in northeastern Brazil. Fever, weight loss, pronounced splenomegaly, hepatomegaly, anemia, thrombocytopenia, relative neutropenia, hypoalbuminemia and hypergammaglobulinemia were found in the majority of patients. Symptoms were often present for two or more months before diagnosis. Secondary infections complicated many cases; there were ten cases of pneumonia and half of the patients had one or more intestinal parasites. The average length of hospital stay was 27 days; all patients were treated with meglumine antimoniate (Glucantime). The mortality rate was 3%. American visceral leishmaniasis remains an important disease among children living in endemic areas.

Acute respiratory viral infections in ambulatory children of urban northeast Brazil.

The morbidity of acute respiratory infections in young children and the role of respiratory viruses were evaluated in a 29-month household-based study in an impoverished urban population in Fortaleza, Brazil; subjects were 175 children less than 5 years of age in 63 families. Home visits were conducted three times weekly during which staff recorded the presence of respiratory and systemic symptoms and collected upper respiratory tract samples for viral isolation. A large and sustained burden of respiratory illness was observed, and respiratory viruses were isolated in 35% of the samples collected. Of the isolates, 45.6% were rhinoviruses, 16% parainfluenza viruses, 15.8% enteroviruses, 9.9% adenoviruses, 7.0% herpes simplex viruses, and 5.7% influenza viruses. The results indicate that poor children in northeast Brazil have a high prevalence of respiratory illness and that rhinovirus is the most frequent respiratory virus.