Aivlosin® in Poultry
ORT
ORT, caused by the bacterium Ornithobacterium rhinotracheale, is a cause of both primary and secondary respiratory disease in chickens and turkeys. In recent years there has been increasing awareness of the significance of ORT as a worldwide cause of disease and economic loss in poultry. There are, however, varying levels of awareness of the disease in different parts of the world due to difficulty of isolation/diagnosis and confusion with other respiratory diseases.
Clinical signs
Spread of the disease
Diagnosis
Management and control
Clinical signs
Infection in broilers may be seen as early as 3 weeks of age and results in reduced growth, mild respiratory signs and increased mortality. In commercial layers and breeders, reduced egg production and egg quality may be evident.
In turkeys, more severe respiratory signs, including sinusitis, are common together with increased mortality. Older birds and those with a concurrent turkey rhinotracheitis (TRT) virus infection are more severely affected. The common post-mortem findings include pneumonia, air-sacculitis and a fibrino-purulent exudate with pericarditis and peritonitis
Spread of the disease
Spread is by horizontal transmission, although its rapid appearance around the world over the past decade may suggest vertical transmission.2
2 Van Empel & Hafez (1999) Avian Pathology 28: 217-227
Diagnosis
Diagnosis can be difficult, as it relies on a combination of clinical signs, post-mortem pathology, isolation of the bacterium and confirmatory ELISA serology. Additionally the bacteria can be difficult to grow, and requires microaerophilic conditions and inclusion of gentamicin or polymyxin to prevent overgrowth with less fastidious bacteria such as E. coli or proteus species.
Management and control
There are a number (17) of different ORT serotypes (A-Q). The major serotype in chickens is type A and a vaccine has been developed using this serotype. However, protection is serotype- specific.
Antibiotics can be used to treat and control the disease caused by all serotypes. Resistance can develop and selection should be based on the sensitivity of the organism.






