Submitted to: Canadian Journal of Veterinary Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/16/2010
Publication Date: 7/1/2011
Citation: Jaglic, Z., Jeklova, E., Christensen, H., Leva, L., Register, K.B., Kummer, V., Kucerova, Z., Faldyna, M., Maskova, J., Nedbalcova, K. 2011. Host response in rabbits to infection with Pasteurella multocida serogroup F strains originating from fowl cholera. Canadian Journal of Veterinary Research. 75(3):200-208. Interpretive Summary: Pasteurellosis caused by Pasteurella multocida is a significant bacterial disease of rabbits and causes considerable economic losses in large production units throughout the world. Although serogroup F strains are predominantly associated with avian infection and fowl cholera outbreaks, a relatively high occurrence of serogroup F strains among rabbit nests has been recently reported. In this study, 2 different serogroup F fowl cholera isolates were tested for their ability to cause disease in rabbits. All infected rabbits showed clinical signs of peracute septicemic disease ending with shock, and died or were euthanized in the terminal stage of the disease 1–2 days post-infection. Histopathological lesions were detected in lungs, heart, liver, kidney and spleen and abnormalities in immune cell function were noted. Uninfected rabbits displayed no signs of disease, no histopatholocal lesions and had normal immune cell function. This study demonstrates that rabbits may be highly sensitive to disease-causing infection with P. multocida serogroup F strains originating from avian hosts and that, in addition to serogroups A and D, serogroup F also is of epizootiological importance in rabbits.
Technical Abstract: The ability of two avian Pasteurella multocida serogroup F strains to induce disease in rabbits was investigated in this study. Two groups of 18 Pasteurella-free rabbits each were intranasally challenged with strains isolated from chicken and turkey, respectively. Half the animals in each challenge group were immunosuppressed using dexamethasone. All the challenged rabbits showed clinical signs of peracute septicemic disease ending with shock, and died or were euthanized in the terminal stage of the disease 1–2 days post-infection. Gross pathological changes included systemic vascular collapse and vascular leak syndrome. Hyperemia, hemorrhages as well as oedematous and degenerative changes were histologically observed in parenchymatous organs. Inflammatory cell infiltrations were infrequently observed. The study has shown that avian P. multocida serogroup F strains are highly virulent in rabbits. The severity of disease observed and the fact that P. multocida serogroup F strains have already been found in commercial rabbit nests (Jaglic et al., J. Vet. Med. B, 2004, 51: 467-469) indicate that serogroup F could play an important epizootiological role in a rabbit host.