Somnogenic, pyrogenic, and hematologic effects of experimental pasteurellosis in rabbits

Abstract

Previous work has demonstrated that intravenous inoculation of rabbits with various microorganisms induces complex time-dependent alterations in sleep as well as other pathophysiological effects typically associated with infectious disease. To evaluate the effects of bacterial challenge that more closely resembles naturally developing disease, we inoculated rabbits with Pasteurella multocida, a common pathogen of this species, using routes of administration that mimic normal routes of exposure. Biphasic sleep alterations characterized initially by enhanced slow-wave sleep and later by decreased slow-wave sleep occurred after intravenous, intramuscular, subcutaneous, or intranasal inoculation. Rapid-eye-movement sleep was inhibited for most of the 48-h period after inoculation. Inoculation by all four routes also induced fever and qualitatively similar hematologic changes. However, the magnitude and specific temporal patterns of both somnogenic changes and other pathophysiological effects varied with the route of inoculation.