Pathogenesis of Ornithobacterium rhinotracheale in egg-laying hens with coexisting infectious bronchitis virus and Escherichia coli infections

SUMMARY Ornithobacterium rhinotracheale (ORT) is recognized as an important respiratory pathogen in turkeys and chickens. The severity of the disease is worsened when birds have coexisting infections with other respiratory pathogens. The objectives of this study were to investigate the pathogenesis of ORT infection with exposure to infectious bronchitis virus (IBV), Escherichia coli, or both in laying chickens. A total of 160 eight-week-old specific pathogen-free White Leghorn chickens were exposed experimentally to 1 of 7 treatments: ORT alone; E. coli alone; IBV alone; ORT + E. coli; ORT + IBV; IBV + E. coli; or ORT + IBV + E. coli. The clinical signs and pathological changes were evaluated in birds from all groups. Birds exposed to ORT or E. coli alone did not show any overt clinical signs. Birds exposed to IBV, ORT + IBV, IBV + E. coli, and ORT + IBV + E. coli exhibited clinical signs that varied from depression and nasal discharge to mortality. The ORT + IBV + E. coli-infected birds exhibited gross lesions, which included hemorrhagic tracheitis, fibrinous pneumonia, airsacculitis, pericarditis, and peritonitis. Histopathological studies of this group revealed distinct pathological changes. Immunohistochemistry staining demonstrated the presence of ORT antigens in the tracheas and lungs of the ORT + IBV + E. coli-infected birds. Mortality after ORT infection was noticed only in the ORT + IBV + E. coli group. We conclude that IBV and E. coli infections exacerbate ORT pathogenesis in adult laying hens. We also conclude that ORT persists in tissues such as the infraorbital sinuses for longer periods without causing significant respiratory disease by itself. This presence of ORT may predispose birds to the development of peritonitis and death with subsequent IBV and E. coli coinfections.

[1]  F. Pasmans,et al.  Significance of interactions between Escherichia coli and respiratory pathogens in layer hen flocks suffering from colibacillosis-associated mortality , 2004, Avian pathology : journal of the W.V.P.A.

[2]  T. Brown,et al.  Evaluation of the Protection Conferred by Commercial Vaccines Against the California 99 Isolate of Infectious Bronchitis Virus , 2003, Avian diseases.

[3]  C. Canal,et al.  Prevalence of Antibodies Against Ornithobacterium rhinotracheale in Broilers and Breeders in Southern Brazil , 2003, Avian diseases.

[4]  A. Musa,et al.  Studies on the Bacterial Etiology of Airsacculitis of Broilers in Northern and Middle Jordan with Special Reference to Escherichia coli, Ornithobacterium rhinotracheale, and Bordetella avium , 2002, Avian diseases.

[5]  H. Hafez.  Diagnosis of Ornithobacterium Rhinotracheale , 2002 .

[6]  K. Nagaraja,et al.  Minimization of Pathologic Changes in Ornithobacterium rhinotracheale Infection in Turkeys by Temperature-Sensitive Mutant Strain , 2002, Avian diseases.

[7]  K. Nagaraja,et al.  Seroprevalence of Ornithobacterium rhinotracheale infection in commercial laying hens in the north central region of the United States. , 2001, Avian diseases.

[8]  T. Fabri,et al.  Ornithobacterium rhinotracheale, a Primary Pathogen in Broilers , 2000 .

[9]  K. Nagaraja,et al.  Ornithobacterium rhinotracheale infection in commercial laying-type chickens. , 2000, Avian diseases.

[10]  K. Nagaraja,et al.  Outer membrane proteins for serologic detection of Ornithobacterium rhinotracheale infection in turkeys. , 2000, Avian diseases.

[11]  H. Hafez,et al.  Ornithobacterium rhinotracheale: A review. , 1999, Avian pathology : journal of the W.V.P.A.

[12]  D. Goovaerts,et al.  Immunohistochemical and serological investigation of experimental Ornithobacterium rhinotracheale infection in chickens. , 1999, Avian pathology : journal of the W.V.P.A.

[13]  K. Nagaraja,et al.  Development of a Serum Plate Agglutination Test to Detect Antibodies to Ornithobacterium Rhinotracheale , 1998, Journal of veterinary diagnostic investigation : official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc.

[14]  K. Nagaraja,et al.  Ornithobacterium rhinotracheale infection in turkeys: experimental reproduction of the disease. , 1998, Avian diseases.

[15]  C. Pope,et al.  Isolation and identification of Ornithobacterium rhinotracheale from commercial broiler flocks on the Delmarva peninsula. , 1997, Avian diseases.

[16]  D. Goovaerts,et al.  Experimental infection in turkeys and chickens with Ornithobacterium rhinotracheale. , 1996, Avian diseases.

[17]  A. Travers.  Concomitant Ornithobacterium rhinotracheale and Newcastle disease infection in broilers in South Africa. , 1996, Avian diseases.

[18]  M. Jackwood,et al.  In vivo evaluation of the pathogenicity of field isolates of infectious bronchitis virus. , 1994, Avian diseases.

[19]  J. Bongers,et al.  [Respiratory problems, growth retardation and arthritis in turkeys and broilers caused by a Pasteurella-like organism: Ornithobacterium rhinotracheale or 'Taxon 28']. , 1994, Tijdschrift voor diergeneeskunde.