Persistent detection of avian influenza A/H7N9 virus among poultry in Huzhou City, China, in the summer of 2013.

In eastern China, live poultry markets were successively re-opened in the summer of 2013 following their closure in April 2013. We detected influenza A/H7N9 RNA with positive rates from 4% to 22.2% among poultry samples in targeted markets in Huzhou City, China, from August 6 to September 24, 2013. Phylogenetic analyses of hemagglutinin and neuraminidase genes confirmed that the strain prevalent among poultry in Huzhou City in the summer of 2013 belonged to the same genotype as those capable of infecting humans. These results raise concern for a further outbreak of H7N9 in the cooler season.