Cohort study of rotavirus serotype patterns in symptomatic and asymptomatic infections in Mexican children.
A cohort of 200 Mexican children from a low income periurban community was monitored from birth to the age of 2 years to determine the serotype-specific incidence, morbidity and seasonal pattern of symptomatic and asymptomatic human rotavirus (HRV) infections. A total of 177 HRV infections occurred in 134 (67%) children; 50% of these infections were asymptomatic. The incidence of all HRV infections was 0.6 episode/child year and was inversely related to age (r = -0.93; P < 0.01). The incidence of HRV-associated diarrhea was 0.3 episode/child year, with the highest frequency and severity occurring in infants between 4 and 6 months of age. HRV infections were more frequent each autumn, with a changing sequential pattern of predominant serotypes. Overall serotype 3 (34%) was the most frequent, followed by serotypes 1 (16%), 2 (15%) and 4 (6%). The 4 serotypes were associated with a similar risk for diarrhea and severity of diarrhea. In 23 (26%) HRV diarrhea-associated infections, an additional enteropathogen was identified; these mixed infections were more frequent in older children (chi square, 4.45; P < 0.05) but were not more severe (chi square, 0.02; P > 0.05). Our data indicate that HRV infections were common early in life, seasonal, frequently asymptomatic and caused by a variety of serotypes, none of which was a risk factor for diarrhea or severity of diarrhea.
Raúl Velázquez
F
F
Department of Infectious Diseases, Instituto Nacional de la Nutrición, Mexico City, Mexico.
Calva
J J
JJ
Lourdes Guerrero
M
M
Mass
D
D
Glass
R I
RI
Pickering
L K
LK
Ruiz-Palacios
G M
GM
D015331:Cohort Studies; D003968:Diarrhea, Infantile / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008800:Mexico / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors; D012401:Rotavirus / Q000145:classification*; D012400:Rotavirus Infections / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D012703:Serotyping; D014505:Urban Population