Analysis on the epidemiological and genetic characteristics of enterovirus type 71 and Coxsackie A16 virus infection in Jiangsu, China

Abstract

To determine the epidemiological features of hand-foot-and-mouth disease (HFMD) outbreaks and the genetic characteristics of enterovirus type 71(EV71) isolates from patients in Lianyungang, Jiangsu province in May, 2008. Epidemiological, microbiological, cellular and molecular methods were performed to investigate pathogens and to describe the homogeneity of isolated strains. 21 cases were reported in this HFMD outbreak with the attack rate as 20.0%. 3 EV71 virus strains were isolated from 10 stool samples. The nucleotide and amino acid homogeneity of these 3 Jiangsu strain with Anhui Fuyang strains were 97.9%-100.0% and 99.7%-100.0%, respectively. These 4 Jiangsu strains were within genotype C sub-geno group C4 in phylogenetic tree. Data from the follow-up study showed that shedding of EV71 and Coxsackie A16 virus (CA16) in the latent period appeared in the outbreak of HFMD. Human beings could be infected by both EV71 virus and CA16 at the same time and could also carry the two viruses. We also discovered that EV71 virus could be expelled out of the human body through stool in the first week and last for 10 weeks. The recently identified EV71 isolates from this HFMD outbreak belonged to sub-geno group C4. Facts as: the release of viruses in the latent period, co-infection or coexisting of two viruses at the same time and super long period of expulsion of toxin exist in EV71 and CA16 did exist.