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==Introduction==

==Introduction==

'''''Ornithobacterium rhinotracheale''''' is a '''gram negative rod shaped [[Bacteria|bacterium]]''' causing '''[[Respiratory System|respiratory]] disease in turkeys and chickens'''. It is the only bacterium currently classified as within the ''Ornithobacterium'' genus.  

'''''Ornithobacterium rhinotracheale''''' is a '''gram negative rod shaped [[Bacteria|bacterium]]''' causing '''[[Respiratory System|respiratory]] disease in turkeys, chickens and other avian species'''. It is the only bacterium currently classified as within the ''Ornithobacterium'' genus <ref name="Hafez">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''</ref>.  

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. Twelve serotypes of ''O. rhinotracheale'' have been distinguished, and are mainly defined geographically.

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.

''O. rhinotracheale'' is not zoonotic.

Worldwide

Worldwide

Transmission is '''vertical through eggs and also aerosolic'''.<ref name="Van Empel">Van Empel, P. C. M., Hafez, H. M (1999) '''Ornithobacterium rhinotracheale: a review.''''' Avian Pathology'', 28(3):217-227.</ref>

Transmission is '''mainly horizontal aerosolic, but also vertical through eggs'''.<ref name="Van Empel">Van Empel, P. C. M., Hafez, H. M (1999) '''Ornithobacterium rhinotracheale: a review.''''' Avian Pathology'', 28(3):217-227.</ref>

==Signalment==

==Signalment==

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.<ref>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</ref>

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.<ref>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</ref>

==Clinical Signs==

==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.

'''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.

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

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

Gastrointestinal signs such as [[Diarrhoea|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, fasciculations and paresis/paralysis.

Gastrointestinal signs such as [[Diarrhoea|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<ref>Veen, L., Empel, P., Fabri, T (2000). '''Ornithobacterium rhinotracheale, a primary pathogen in broilers.''' ''Avian Diseases'', 44(4):896-900; 6</ref>. 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.

''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<ref name="Van Empel" /> and [[immunofluorescence]]''' are also possible.<ref>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</ref>  

'''Agar gel precipitation''' can be used for serological diagnosis and serotyping. '''[[ELISA testing|ELISA]] and serum agglutination''' can be used to detect antibodies to ''O. rhinotracheale''.

''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<ref name="Van Empel" />, immuno-histochemical staining and [[immunofluorescence]]''' are also possible.<ref>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</ref>

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.<ref>Veen, L., Empel, P., Fabri, T (2000). '''Ornithobacterium rhinotracheale, a primary pathogen in broilers.''' ''Avian Diseases'', 44(4):896-900; 6</ref> 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.

'''Agar gel precipitation''' can be used for serotyping. '''[[ELISA testing|ELISA]] and serum agglutination''' can be used to detect antibodies to ''O. rhinotracheale''.

==Treatment==

==Treatment==

==Control==

==Control==

'''Vaccinations are under development''' and experimental trials suggest that vaccinating 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 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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[[Category:CABI Expert Review]]

[[Category:CABI Expert Review]]

[[Category:Flavobacteria]]

[[Category:Flavobacteria]]

[[Category:Alimentary Diseases - Birds]]

[[Category:Alimentary Diseases - Birds]]

[[Category:Reproductive Diseases - Birds]]

[[Category:Reproductive Diseases - Birds]]