A prospective study of astrovirus diarrhea of infancy in Mexico City.
OBJECTIVE
To describe the epidemiologic and clinical characteristics of astrovirus-associated diarrhea in a cohort of young children from a periurban community in Mexico City.


METHODS
From November, 1988, through December, 1991, a total of 214 children were enrolled in a longitudinal study of diarrhea and monitored from birth to 18 months of age. A stool specimen was collected during each episode of diarrhea. Specimens from a total of 510 diarrhea episodes were tested for astrovirus by enzyme immunoassay and examined for other enteric pathogens. The antigenic 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 was characterized by a median of 4 stools (range, 2 to 10) during the first 24 h, a median duration of 3 days (range, 1 to 21), vomiting (20%), and fever (7%). No cases of dehydration or repeat symptomatic infections were observed. Coinfection with another pathogen was detected in 11 of the 26 episodes (42%). Serotype 2 (35%) was most common, followed by serotypes 4 (15%), 3 (11%), and 1 and 5 (4% each); 31% were nontypable. 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 diarrhea in this cohort of young Mexican children and presented as a mild secretory diarrhea. Five predominant antigenic types were detected with type 2 being the most common.
Guerrero
M L
ML
Department of Infectious Disease, National Institute of Nutrition, Mexico City, Mexico.
Noel
J S
JS
Mitchell
D K
DK
Calva
J J
JJ
Morrow
A L
AL
Martínez
J
J
Rosales
G
G
Velázquez
F R
FR
Monroe
S S
SS
Glass
R I
RI
Pickering
L K
LK
Ruiz-Palacios
G M
GM
D019350:Astroviridae Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D015331:Cohort Studies; D003968:Diarrhea, Infantile / Q000453:epidemiology* / Q000821:virology*; D005243:Feces / Q000821:virology; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D001257:Mamastrovirus / Q000302:isolation & purification*; D008800:Mexico / Q000453:epidemiology; D011247:Pregnancy; D011446:Prospective Studies