Ornithobacterium rhinotracheale

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Ornothobacterium rhinotracheale
Phylum Bacteroidetes
Class Flavobacteria
Order Flavobacteriales
Genus Ornithobacterium
Species Ornithobacterium rhinotracheale


Ornithobacterium rhinotracheale is a gram negative rod shaped bacterium causing respiratory disease in turkeys, chickens and other avian species. It is the only bacterium currently classified as within the Ornithobacterium genus [1].

The bacterium is non-haemolytic and can tolerate a range of aerobic/anaerobic conditions and colonise a variety of agars. Colonies are smooth and non-pigmented. Eighteen serotypes of O. rhinotracheale have been distinguished.

O. rhinotracheale is not zoonotic.



Transmission is mainly horizontal aerosolic, but also vertical through eggs.[2]


Birds of all ages can be affected.

In turkeys, disease is more severe in adult birds from market age onwards.[3]

Male birds also appear to be more susceptible to clinical signs and mortalities.[4]

Disease is seen primarily in broiler chickens and meat turkeys but also affects layers. Various wild birds including pheasants, partridges, guinea fowl and rooks have also been found to be infected.[5]

Clinical Signs and Gross Lesions

Nasal discharge, dyspnoea, sneezing and a productive cough which may yield blood represent the purulent pneumonia caused by O. rhinotracheale infection. Birds often exhibit severe growth retardation and mortalities within the flock will increase.

O. rhinotracheale has also been associated with hatching problems in chickens and turkeys[6] and production of soft-shelled misshapen eggs.

Infection can also spread haematogenously to the joints and cause lameness and swelling.

Gastrointestinal signs such as diarrhoea and concurrent weight loss and ill thrift are seen in some birds. Neurological signs may also develop in severe cases, usually consisting of tremors and paresis/paralysis.

The most common post-mortem signs seen are air sacculitis and pneumonia but inflammatory suppurative lesions may be seen throughout the respiratory tract. The lungs and air sacs are infiltrated by lymphocytes and polymorphonuclear heterophils when examined histologically[7]. Degenerative changes may also be seen within the muscles and tendons. In turkeys, a serofibrinous pneumonia is seen and blood is often present in the trachea and bronchi. Coagulative necrosis of the liver is sometimes seen.

Laboratory Diagnosis

O. rhinotracheale is most commonly isolated and cultured from the trachea and lungs, but is possible from other organs. Blood agar is usually used for culture but overgrowth of other bacteria is a common complication. PCR[2], immuno-histochemical staining and immunofluorescence are also possible.[8]

Agar gel precipitation can be used for serotyping. ELISA and serum agglutination can be used to detect antibodies to O. rhinotracheale.


No specific treatment is available and resistance to antibiotics is common. Therefore culture and sensitivity is recommended where O. rhinotracheale infection is suspected. Single and combination protocols involving oxytetracyclines, chlortetracycline, tiamulin, penicillins, spectinomycin and ceftiofur have been used but response is unpredictable.


Vaccinations are under development and experimental trials suggest that vaccinating broiler breeders with a bacterin and progeny with a live vaccine at 2-3 weeks old is the most effective method of controlling O. rhinotracheale. Vaccinations of breeding and fattening turkey flocks with autogenic inactivated oil-adjuvant vaccines were proven to be successful in reducing the outbreaks of O. rhinotracheale.

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  1. Hafez, H.M. and P. Vandamme (2011). Genus XXVI..Ornithobacterium Vandamme, Segers, Vancanneyt, Van Hove, Mutters, Hommez, Dewhirst, Paster, Kersters, Falsen, Devriese, Bisgaard, Hinz and Mannheim 1994, 35VP. In: Bergey’s Manual of Systematic Bacteriology 2nd. Ed. (ed Krieg et al.), volume 4, 250-314. Springer
  2. 2.0 2.1 Van Empel, P. C. M., Hafez, H. M (1999) Ornithobacterium rhinotracheale: a review. Avian Pathology, 28(3):217-227.
  3. Roepke, D. C., Back, A., Shaw, D. P., Nagaraja, K. V., Sprenger, S. J., Halvorson, D. A (1998) Isolation and identification of Ornithobacterium rhinotracheale from commercial turkey flocks in the upper midwest. Avian Diseases, 42(1):219-221; 7
  4. Zormal- Rojs, O., Zdovc, I., Bencina, D., Mrzel, I (2000) Infection of turkeys with Ornithobacterium rhinotracheale and Mycoplasma synoviae. Avian Diseases, 44(4):1017-1022.
  5. Leroy- Sétrin, S., Flaujac, G., Thénaisy, K., Chaslus-Dancla, E (1998) Genetic diversity of Ornithobacterium rhinotracheale strains isolated from poultry in France. Letters in Applied Microbiology, 26(3):189-193; 16
  6. E-Gohary, A. A (1998) Ornithobacterium rhinotracheale (ORT) associated with hatching problems in chicken and turkey eggs. Vet Med J Giza, 46(2):183-191; 19
  7. Veen, L., Empel, P., Fabri, T (2000). Ornithobacterium rhinotracheale, a primary pathogen in broilers. Avian Diseases, 44(4):896-900; 6
  8. Lombardi, G., Vinco, L. J., Belloni, G. P., Alborali, G. L (1999) Incidence of Ornithobacterium rhinotracheale (ORT) in some turkey farms in Northern Italy: field observations and diagnosis. Selezione Veterinaria, No. 8/9:595-602; 15


This article was originally sourced from The Animal Health & Production Compendium (AHPC) published online by CABI during the OVAL Project.

The datasheet was accessed on 22 June 2011.

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