Environmental connections of novel avian-origin H7N9 influenza ...

6 Li J, et al. Sci China Life Sci June (2013) Vol.56 No.6Figure 3 Chromatogram of the HA sequences flanking the amino acids atposition 226. The dashed boxes show the nonsynonymous substitutions.The 226I substitution in the HA of Hangzhou/1 is compared with the 226Lin the other three viruses.in the newly-emerging H7N9 virus.3 DiscussionWe described three infected cases in Hangzhou City andidentified the novel reassortant influenza A (H7N9) virusesin the respiratory specimens from these patients, as well asfrom environmental samples. Hangzhou City is close toShanghai Municipality, where the first influenza A (H7N9)virus infections were reported [1]. Although later than thecases in Shanghai Municipality, the onset of the illness oftwo of the patients described here was reported around thesame time as the illness of the patient in Anhui Province.Two of the three patients had a history of direct contact withlive poultry or with local free markets. A closely relatedH7N9 virus was identified in the contacted environment ofPatient 2. These data may provide direct evidence for thelinking, or even transmission, of the avian H7N9 viruses tohumans in these adjacent provinces of east China.Although the clinical characteristics of the three casesreported here are very similar to the early cases reportedpreviously in Anhui and Shanghai, namely high fever andsevere respiratory symptoms, the genetic diversity of thegenomes of the new Hangzhou H7N9 viruses was determined.The H7 phylogenetic trees placed the Hangzhou/1,Hangzhou/2 and Hangzhou/3 viruses on separate branches.Within the HA, NA and PB2 sequences from all the publiclyavailable H7N9 viruses, we identified 36 sites with atleast one amino acid mutation (Table 2). These data mayindicate the independent and rapid evolution of the virusesin the natural reservoir and their independent introduction tohuman. However, based on the currently available H7N9virus sequences, we found a series of other substitutions themajority of which were synonymous mutations (Table S2).The effects of these substitutions on the fitness of the virus-Figure 4 Map of China showing the substitutions in the host-signatures from the different virus sequences. The provinces and municipal cities with reportedH7N9 cases are in brown. The features of each of the sites are shown as follows: Province (number of human cases+number of environment/poultrycases), Gene (amino acid position): Residue (human); Residue (environment/poultry). Residues with avian-signatures are in purple; residues with mammalsignaturesare in yellow. The 226I in the HA from A/Hangzhou/1/2013 is highlighted in red.