Epidemiology of postshigellosis persistent diarrhea in young children.

Background: Dysentery accounts for 20% of the 4.6 million diarrhea-associated deaths among children in developing countries, with the risk from death in dysenteric persistent diarrhea 10-fold higher than that in acute dysentery. Although Shigella accounts for the majority of dysenteric episodes, very little is known about the epidemiology of postshigellosis persistent diarrhea.

Methods: Rural Bangladeshi children younger than 5 years of age (n = 1,756) were followed for 1 month after exposure to sentinel cases of Shigella dysentery. The likelihood of an acute diarrheal episode becoming persistent was assessed.

Results: Diarrhea caused by Shigella was significantly associated with an increased risk of persistent diarrhea (age-adjusted relative risk, 1.83; 95% confidence interval, 1.19 to 2.81). Despite the use of nalidixic acid in dysenteric episodes, persistent diarrhea occurred in 23% of children with shigellosis. Infection by multiply antibiotic-resistant Shigella isolates (age-adjusted relative risk, 3.76; 95% confidence interval, 1.51 to 9.36) and occurrence of shigellosis during infancy were observed to be risk factors for initiation of Shigella diarrhea persistence. However, 88% of the persistent shigellosis episodes occurred in older children, 50% were associated with nondysenteric shigellosis and 79% were caused by Shigella species other than Shigella dysenteriae 1.

Conclusions: These data demonstrate the importance of Shigella as a cause of persistent diarrhea and indicate that strategies to prevent postshigellosis persistent diarrhea must be broad-based, with a focus on older children as well as infants, management of nondysenteric as well as dysenteric disease and prevention of diarrhea caused by multiple Shigella species.