[Experimental model of associated influenza-para-influenza infection].

An experimental model of associated influenza-parainfluenza infection has been developed. Simultaneous inoculation of mice with influenza A2/21/65 and parainfluenza type 3 or inoculation with these viruses at an interval of 24 hours was shown to produce a considerably more severe disease as manifested by the development of severe confluent pneumonias involving both lungs and death of the inoculated animals. The animals with the associated infection showed no significant difference in antibody titers or the intensity of immunity as compared with control groups (influenza or parainfluenza monoinfection). The development of the mixed infection was accompanied by the inhibition of neutrophilic and macrophage phagocytosis and inhibition of interferon production.