Pasteurella multocida-toxin induced atrophic rhinitis in piglets

Progressive atrophic rhinitis (AR) is a complex of disease symptoms caused by infection with toxigenic Pasteurella multocida . Environmental and animal factors contribute to the severity of the disease. Their impact and relationship with severity of disease are inadequately understood and remain to be quantified in their effects. In this thesis, two areas of interest in atrophic rhinitis have been studied. A challenge model with Pasteurella multocida derived toxin (Pm-T) to mimic the disease was developed. Next, the impact of some aspects of climatic environment and the relationship with the severity of AR on health and metabolism of piglets were studied. Furthermore, investigations on the role of the immune system in atrophic rhinitis have been conducted with emphasis on mechanisms underlying the apparent lack of conventional (classic) immune responses to Pm-T. The Pm-T challenge resulted mainly in a lower food intake with concomitant lower weight gain, and in a reduced heat production caused by decreased activity of the pigs. Immunological features of Pm-T suggest T cell involvement in the pathogenesis of AR. Though the immune responses during AR remain far from understood, it is hypothesized that AR has autoimmune like features, with Pm-T triggering T cells to initiate destruction of nasal bony tissue.