Molecular epidemiology of human astrovirus diarrhea among children from a periurban community of Mexico City

Human astroviruses (HAstVs) were detected in 23 stool samples from 365 diar rhea episodes among 214 children (<18 months old) prospectively monitored f or diarrhea in Mexico City. Stool samples were tested by EIA and reverse tr anscriptase-polymerase chain reaction (RT-PCR) analysis. EIA was less sensi tive (74%) and equally specific, compared with RT-PCR analysis using type-c ommon primers for HAstV detection. Of 31 HAstV isolates, EIA typed 18 (69%) of 26 EIA-positive samples, and RT-PCR analysis typed 26 (84%) of 31 RT-PC R-positive samples. Phylogenetic analysis of the 3' end of the capsid regio n (363 nucleotides) confirmed the type assignment by EIA and RT-PCR analysi s and determined the type for 5 previously untyped samples. Six HAstV antig enic types cocirculated in the community: HAstV-2 (42%), HAstV-4 (23%), HAs tV-3 (13%), HAstV-1 (10%), HAstV-5 (6%), and HAstV-7 (6%). RT-PCR and seque nce analysis provided more detailed epidemiology of HAstV in the community than did antigenic detection methods.