EXPERIMENTAL TRANSMISSION OF INFLUENZA VIRUS INFECTION IN MICE. I. THE PERIOD OF TRANSMISSIBILITY.

An experimental model has been developed for the reproducible transmission of influenza virus infection from experimentally infected mice to uninfected cage mates. Infector mice transmit influenza virus infection most readily during the period 24 to 48 hours after initiation of their infection. This restricted period of transmission is not due to declining titers of infective virus in the nose, trachea, or lungs of infector mice after 48 hours of infection, since peak titers in these tissues are maintained for another 48 hours. A mouse-adapted strain of A2 virus was found to be more readily transmitted than the mouse-adapted CAM strain of influenza A1 virus, although the CAM strain induced higher pulmonary virus titers and more extensive lung lesions.