The local origin of fever in influenza: Differential production of endogenous oxygen by nasal inflammatory cells of ferrets exhibiting different levels of fever



Virulent influenza viruses produce greater fevers in ferrets than attenuated strains. The levels of endogenous pyrogen (EP), as measured in rabbits, released by nasal inflammatory cells taken from febrile ferrets infected with one of 2 virulent or 4 attenuated strains of influenza virus and incubated in vitro, correlated with the levels of fever produced by these strains in vivo. These results support previous work which indicated that fever results from release of EP from virus phagocyte interaction in the upper respiratory tract [3]. They also support other evidence [12,13] that virus strains differ in capacity to induce EP from phagocytes.