Aging and the response to Salmonella infection.

We investigated the effect of age on the ability of Fischer 344 rats to mount a febrile response and contain infection due to Salmonella typhimurium. Elderly (22-23 month), middle-aged (12-13 month) and young (2-3 month) rats were inoculated intraperitoneally with 1.5 X 10(6) organisms and the febrile response and liver and spleen bacterial counts were followed for 13 days. The elderly had a more sluggish febrile response and did not achieve as great a maximum temperature elevation as the young and middle-aged rats. Except for days 1 and 5, bacterial counts in liver and spleen were greater in the elderly rats than in young and middle-aged rats.