Identification of human Astrovirus infections among children with acute gastroenteritis in the southern part of Vietnam during 2005-2006

A molecular epidemiological study on common diarrheal viruses was conducted in a children's hospital in Ho Chi Minh City between December 2005 and November 2006. Fecal samples were collected from 502 pediatric patients with acute gastroenteritis, and were screened for eight types of viral agents. Human astroviruses (HAstVs), which were detected with a prevalence of 13.9%, became the second most frequent viral enteropathogen. Although detected in both dry and rainy seasons, the majority (92.8%) of HAstVs in this study were found in the rainy season. Patients aged between 6 and 23 months were found to be more infected from astrovirus when compared to other age groups. The ratio between boys and girls was 2.3:1. The overall mean severity score of astrovirus positive patients was 11.8 +/- 2.45. The mean severity score of the inpatients was statistically higher than that of the outpatients; however, there was no difference in severity scores between the age groups observed. The clinical manifestations of astrovirus infections among the Vietnamese children were diarrhea, vomiting, fever, coughing, and coryza. All of the detected astroviruses belonged to genotype 1. The phylogenetic tree clearly indicated that HAstVs-1 worldwide could be classified into four different lineages, in which, Vietnamese astroviruses and other recently isolated strains from other countries clustered into the distinct lineage, 1d. These results provide important information on astrovirus infections among Vietnamese children.