Molecular Epidemiology Of Astrovirus Infection In Infants In Jilin And Lanzhou, China

Objective:To investigate the status of astrovirus infection and its clinical manifestation and epidemiological features in the areas of both Jilin and Langzhou, China, for obtaining fuller epidemiologic data to supply a basis for the control and prevention of viral diarrhea in China mainland.Methods:Between Oct.2007 and Oct.2008, we obtained 417 stool specimens from the children with diarrhea, who lived in areas of Jilin, were younger than 5 years, and additional 291 stool collections from the younger subjects of less than 5 year-old dwelling in areas of Langzhou, during Oct.2009 and 2010, and detected the astroviruses with one-step PCR method as previously described. Initial screening was performed with partial nucleotide fragment from astrovirus genome ORF1b region, followed by classification with partial segment of ORF2.Results:Seventeen human astrovirus(HAstV) isolates were detected in stool samples from 708 children (2.4%), in which 7 were found in Jilin area and 10, in Lanzhou area. Polymerase analysis on the region of ORF2 revealed that the positive fecal samples were human astrovirus type 1 (HAstV-1) except for one strain of lineage 1 a colony, and the remaining were colony of lineage 1 b. The findings also suggested that HAstV primarily affected children under the age of 2 and was commonly prevalent in spring seasons in Jilin areas compared to epidemic seasons of both spring and autumn in areas of Lanzhou.Astrovirus could result in such symptoms as diarrhea, vomiting and febrile. Simple HAstV infection had no difference with clinical symptoms of enteric adenovirus invasion, and that was true with Non-AdF as compared with enteric adenovirus infection. Combined HAstV infection was found with delayed course of vomiting. Multiple linear regression analysis showed that ages, temperature and territory towards southeast were associated with progress of diarrhea, which was found the longest. Contrarily, the intensity factors were involved in the years and months of prevalence, rates of rotavirus and location towards further west. Diarrhea was found severest once there should be HAstV coinfection with rotavirus.Conlusion:Astrovirus is an important causative agent for infants and younger children with viral diarrhea, characterized by type of HAstV-1. Children younger than 2-year-old are high-risk population, and the epidemic seasons differ a lot from area to another.