A PROSPECTIVE-STUDY OF ASTROVIRUS DIARRHEA OF INFANCY IN MEXICO-CITY

Aim. To describe the epidemiologic and clinical characteristics of ast rovirus-associated diarrhea in a cohort of young children from a periu rban community in Mexico City. Methods. From November, 1988, through D ecember, 1991, a total of 214 children were enrolled in a longitudinal study of diarrhea and monitored from birth to 18 months of age. A sto ol specimen was collected during each episode of diarrhea, Specimens f rom a total of 510 diarrhea episodes were tested for astrovirus by enz yme immunoassay and examined for other enteric pathogens. The antigeni c types of astrovirus were determined by a typing enzyme immunoassay, Results. Astrovirus was detected in 26 (5%) of 510 diarrhea episodes, with an incidence rate of 0.1 episode/child year; the highest rate was in children 13 to 18 months of age. Astrovirus-associated diarrhea wa s characterized by a median of 4 stools (range, 2 to 10) during the fi rst 24 h, a median duration of 3 days (range, 1 to 21), vomiting (20%) , and fever (7%). No cases of dehydration or repeat symptomatic infect ions were observed, Coinfection with another pathogen was detected in 11 of the 26 episodes (42%). Serotype 2 (35%) was most common, followe d by serotypes 4 (15%), 3 (11%), and 1 and 5 (4% each); 31% were nonty pable. Astrovirus-associated diarrhea was less severe, as measured by the number of stools (4.3 +/- 1.9), than diarrhea caused by rotavirus (7.1 +/- 2.8) or when coinfections occurred (5.5 +/- 1.6; P = 0.008). Conclusions, Astrovirus was associated with 5% of the episodes of diar rhea in this cohort of young Mexican children and presented as a mild secretory diarrhea, Five predominant antigenic types were detected wit h type 2 being the most common.