The localization of influenza virus: minimal infectious dose determinations and single cycle kinetic studies on organ cultures of respiratory and other ferret tissues.

A comprehensive survey of ferret tissues in organ culture showed that influenza virus (A/Moscow/1019/65 (HN)) can infect bladder, uterus, oviduct and conjunctiva in addition to respiratory tissues. Alimentary tract tissues were insusceptible, except oesophagus and pharynx which were infected at high inocula. Muscle, reticuloendothelial tissues, blood vessels and kidney were also insusceptible. Minimal infectious dose determinations on the susceptible tissues showed significant differences in the ease of initiation of infection in the order nasal turbinates > bladder > uterus > trachea > lung > conjunctiva > oviduct > oesophagus. On the other hand, the susceptible tissues were similar with respect to the kinetics of virus replication over one infection cycle, new virus appearing from all tissues at about the same time (5-6 hours) after inoculation. Large inocula of virus disappeared very quickly from the blood stream of ferrets yet ferret blood could not inactivate large quantities of virus although it inhibited smaller quantities. The results are discussed in relation to the degree of confinement of influenza infection to the respiratory tract.