The Journal of infectious diseases
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Diarrhea is a leading cause of death in tropical countries. One of the highest childhood mortalities is in northeastern Brazil, where little is known about the morbidity, etiology, and risk factors of diarrhea. Prospective village surveillance over 30 months revealed diarrhea attack rates of more than seven episodes per child-year at six to 11 months of age among the children of the poorest families. ⋯ Enterotoxigenic Escherichia coli and rotaviruses were the most common pathogens, accounting for 21% and 19% of cases, respectively, followed by Shigella species (8.0%), Campylobacter jejuni (7.5%), Giardia species (6.7%), Strongyloides species (5.3%), and enteropathogenic E coli serotypes (4.6%). Most (84%) enterotoxigenic E coli were isolated during the rainy season of October to March (P less than 0.03), whereas 71% of rotaviral illnesses occurred during the drier months of June to October (P less than 0.03). In the present study, the early occurrence and nutritional impact of diarrhea and weaning, as well as the major etiologic agents of diarrhea and their different seasonal patterns have been defined for this region in which life-threatening diarrhea is endemic.
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The epidemiology of Vibrio cholerae O1 El Tor in rural Bangladesh was examined with a new phage-typing system for characterization of individual strains. During a two-year period, 537 strains were typed with a set of standard and experimental phages. Four major and many minor patterns were identified, some associated with discrete outbreaks of disease and others persisting for the entire period. ⋯ The yearly cholera seasons began with the emergence of strains of many different phage types in many different locations; this pattern is consistent with an environmental reservoir for V cholerae. Each patient with cholera excreted only one phage type over time, whereas some family members were infected with strains of different phage types. Phage typing can be a useful marker with which the spread of cholera strains can be traced in endemic settings.