Background: To analyze the genetic and antigenic characteristics of human H5N1 virus isolated from the mainland of China.
Methods: The hemagglutinin (HA) gene of human H5N1 virus were sequenced and analyzed.
Results: The results of HA gene sequencing showed that all the virus isolates belong to the same group because of the high similarity, but they were different from the virus isolated from Thailand and Vietnam. The sequence data also showed that the receptor specificity and the connecting peptide between HA1 and HA2 are still avian influenza origin.
Conclusion: The virus isolates from mainland of China until now belong to the same group and are different from the virus isolated from Thailand and Vietnam, and there is no evidence showing the human-avian influenza reassortant and recombination.