Time-course investigation of infection with a low virulent Pasteurella multocida strain in normal and immune-suppressed 12-week-old free-range chickens

Research output: Contribution to journalJournal articleResearchpeer-review

P.G. Mbuthia, L.W. Njagi, P.N. Nyaga, L.C. Bebora, U. Minga, Jens Peter Christensen, John Elmerdahl Olsen

Twelve-week-old indigenous chickens, either immune-suppressed using dexamethasone (IS) or non-immune-suppressed (NIS), were challenged with a low virulent strain, Pasteurella multocida strain NCTC 10322(T), and developed clinical signs and pathological lesions typical of chronic fowl cholera. NIS birds demonstrated much more severe signs of fowl cholera than IS birds. With few exceptions, signs recorded in IS and NIS birds were of the same types, but significantly milder in the IS birds, indicating that immune suppression does not change the course of infection but rather the severity of signs in fowl cholera. P. multocida signals by fluorescent in situ hybridization (FISH) were observed between 1 h and 14 days in the lungs, trachea, air sacs, liver, spleen, bursa of Fabricius and caecal tonsils, while signals from other organs mostly were observed after 24 h. More organs had FISH signals in NIS birds than in IS birds and at higher frequency per organ. Many organs were positive by FISH even 14 days post infection, and it is suggested that these organs may be likely places for long-term carriage of P. multocida following infection. The present study has demonstrated the spread of P. multocida in different tissues in chickens and distribution of lesions associated with chronic fowl cholera, and pointed to a decrease of pathology in IS birds. Since dexamethasone mostly affects heterophils, the study suggests that these cells play a role in the development of lesions associated with chronic fowl cholera in chickens.
Original languageEnglish
JournalAvian Pathology
Volume40
Issue number6
Pages (from-to)629-637
Number of pages9
ISSN0307-9457
DOIs
Publication statusPublished - 2011

    Research areas

  • Analysis of Variance, Animals, Bacterial Load, Chickens, Cholera, Dexamethasone, Histological Techniques, Immunosuppression, In Situ Hybridization, Fluorescence, Pasteurella Infections, Pasteurella multocida, Poultry Diseases, Time Factors
  • LIFE

ID: 38172015