Elevation of nasal viral levels by suppression of fever in ferrets infected with influenza viruses of differing virulence.

The effect of suppression of fever on viral levels in nasal washes of ferrets infected with either of two clones (7a, virulent; 64d, attenuated) of the recombinant influenza virus A/Puerto Rico/8/34-A/England/939/69 (H3N2) was studied. The febrile response was reduced by shaving the ferrets or by treating them with sodium salicylate, which had no noticeable effect on the inflammatory response. For both clones, significantly more virus was shed in the nasal washes of ferrets whose febrile response was suppressed, and the viral levels decreased less rapidly than in untreated ferrets or in those in which the treatments were ineffective.