Isolation and Identification of H7N2 Avian Influenza Virus Strain CK/HB/1/02 in China

A virus isolate from domestic chicken agglutinated chicken erythrocytes and was found as globular enveloped virion of 90nm-100nm diameters under TEM. The isolate was identified as H7N2 Avian influenza virus(AIV) by HI and NI assays and designated as A/Chicken/Hebei/1/ 2002(H7N2,or briefly as CK/HB/1/02. After inoculating to SPF chicken, the virus was recovered from cloacal swabs and the antibody to H7 was detected at 7 days post-infection (DPI). The IVPI was 0. 00 and postmortem examination showed hemorrhages in several tissues and organs indicating that the virus was LPAIV. HA gene of the isolate exhibited 99. 4% nucleotide sequence identity to A/Afri. Star. /Eng-Q/79(H7N1) virus, 96. 8%-98. 2% to H7N2 virus isolated from Italy and Israel, and only about 81. 0% to American H7N2 Strain. The amino acid at the cleavage site of HA is -KGR-GLF-, which implies the isolate should be of low pathogenicity.