Molecular epidemiological analysis of ECHO19 virus isolated from Yunnan province of China

Objective To explore the VP1gene characteristics and molecular epidemiology of echovirus 19(E19)isolated from acute flaccid paralysis(AFP)cases and healthy children from Yunnan province of China from 1997to 2013. Methods RT-PCR was done to amplify the VP1gene from isolated non-polio enteroviruses(NPEVs),PCR products were sent to Sangon Biotech Co.Ltd.(Shanghai,China)for sequencing by fluorescent labeled Sanger method.The sequences were edited by Sequencher 4.0software,and the virus serotypes were determined according to Obester′s method.E19sequences and molecular epidemiologic features were analyzed and compared with that downloaded from the GenBank.The phylogenetic tree was constructed by using 1 000bootstrap values for statistical analysis. Results Altogether there were 26E19virus strains were isolated from 3 750 AFP cases and healthy children in Yunnan province of China from 1997to 2013.Phylogenetic analysis with other 28strains in GenBank showed that these 54E19strains were grouped into 6genotypes.E19viruses isolated from different sources(AFP or healthy children)and different times were mainly clustered into genotypes 2,4and 5with multiple geographical and time characteristics. Conclusions Continuous molecular surveillance for enteroviruses from AFP cases and healthy children by sequencing is a very important tool for conducting molecular epidemiological study and identifying the disease transmission pathways in Yunnan province of China.