Epidemiology of postshigellosis persistent diarrhea in young children

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.

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.

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.

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.