[Temporal fluctuation and genetic characterization of echovirus 11 isolates upon surveillance of environmental sewage in Shandong Province, China].

We wished to analyze the genetic characterization of echovirus 11 (Echo11) from samples of environmental sewage in Shandong Province (China). The VP1 coding region was typed as the strains were amplified. Phylogenetic analyses on the VP1 sequences from these isolates, strains isolated from AFP cases in the period 1994-2010 and others published in GenBank were conducted. From 2011 to 2012, 94 Echo11 strains were isolated from samples of environmental sewage in Jinan and Linyi City in Shandong Province. Numbers of Echo11 were seasonal and reached peaks in the summer and autumn in both cities; A- mong these isolates, nucleotide (nt) identities were 89.5%-100.0% whereas amino acid (aa) identities were 95.4%-100.0%. The nt and aa identities were 76.6%-79.7% and 90.4%-92.5% between those strains and the prototype (Gregory) strain of Echo11, respectively. All isolates from Shandong Province were the A genotype and the strains evolved very rapidly, which suggested that several transmission chains was co-circulating. We described the temporal fluctuation and genetic characterization of Echo11 isolates from surveillance of environmental sewage in Shandong Province, thereby providing important information for exploring the dynamic change and genetic variation of circulating human enteroviruses in this Province in China.