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Over the last three years in the United States, there has been significant cases of Ornithobacterium rhinotracheale (ORT), especially in turkeys, making this disease worrying. If in 2015 it was casuistically put it in number 7 of the most frequent diseases in turkeys, in 2016 it jumped to the fourth position and then to third place by 2017. ORT is a pleomorphic gram positive bacterium that causes:
Stunted growth
Decreased egg laying
Mortality in severe cases for all types of birds, especially in turkeys and broilers.
It was first identified in 1994 and the rise in cases due to its highly contagious characteristic is increasing year by year. It is more than likely that the pathogen has been overlooked for years due to lack of identification and that cases of respiratory diseases have not been well diagnosed. Seven serovars have been identified – Empel et al. 1997–, with type A being the most frequent at 95% of identifications.
In turkeys, field cases are usually more frequent between 23 and 42 weeks of age and in broilers between 4 and 6 weeks. The incubation period of the disease stands between 48 and 72 hours.
The airway is the fastest and most common route of transmission, although it can also be via the transovarian route. There are discrepancies regarding its pathogenicity, varying according to the isolates studied and the state of the affected birds. The clinical signs produced, its duration, morbidity and mortality are extremely variable, exacerbated by poor management (inadequate ventilation, high density of animals, poor litter quality, etc.) and by other persisting diseases.
A more severe respiratory condition has been observed when associated with Escherichia coli. The respiratory symptoms observed are:
Rhinitis
Coughing up bloody mucus
Inflammation of the infraorbital sinuses
Wattle edema
Tracheitis
Conjunctivitis or dyspnea
The nervous signs are due to instabilities, as a results of an affection in the head and the locomotor symptoms to arthritic processes.
Lesions seen are limited to the infraorbital sinuses, tracheae, air sacs, lungs, and femoro-tibi-tarsal joints. -Photo 1-.
In thoracic and abdominal air sacs, the existence of a foamy yellowish exudates with caseous accumulations is observed –Photo 2–.
Diagnosis in the field is usually difficult as it depends on the symptoms and post-mortem lesions. The laboratory diagnosis with positive confirmation from ELISA or isolation of the bact...
