Replication of avian and seasonal influenza viruses in human bronchus and lung

Abstract

BACKGROUND: Pandemics of 1957 and 1968 were believed to arise from avian influenza viruses.1 The tropism of avian and human seasonal influenza viruses for the human lower respiratory tract deserves investigation. The target cell types that support replication of avian influenza A viruses in the human respiratory tract in the early stages of clinical infection have not well defined. In a previous autopsy studies of human H5N1 disease, influenza A virus were found to infect alveolar epithelial cells2 and macrophages.3 In this study, viral infectivity and replication competence of human and high and low pathogenic avian influenza viruses were systematically investigated in the human conducting and lower respiratory tract using ex vivo organ cultures. We compared the replication kinetics of human seasonal influenza viruses (H1N1 and H3N2), low pathogenic avian influenza viruses (H9N2, H5N8) with that of the highly pathogenic H5N1 viruses isolated from human H5N1 disease …