Turkey Coryza
Synonyms
Bordetellosis orBordetella avium
Bordetella avium rhinotracheitis (BART), alcaligenes rhinotracheitis (ART), acute-respiratory disease syndrome and turkey rhinotracheitis are also terms which have been used in the past for this disease.
Introduction
Turkey Coryza is a highly contagious upper respiratory tract infection (rhinotracheitis) of turkeys, most commonly between the age of 2-8weeks of age, caused by Bordetella avium. Turkeys are thought to be the natural host, however the disease has also been seen in the chicken and in ducks.
Pathogenesis
The disease is usually of sudden onset within the flock and morbidity may reach 100% within 24 hours. Mortality varies, but is usually understood to be a disease of high morbidity and low mortality, however, mortality rates will rise if concurrent infections are present in the flock and if ventilation and environmental conditions are poor.
The bacteria is highly contagious, meaning disease is easily transmitted by direct contact and also from bedding, litter and housing. B. avium is thought to be able to survive for 1-6 months in the environment in contaminated litter
Clinical signs
Signs that will occur suddenly in the flock following a Boredetella avium outbreak include sneezing, coughing, presence of a foamy conjunctivitis around the medial canthus of the eye and open- mouth breathing.
The head of the bird including the feathers will appear wet then proceed to have a brown crusted exudate over parts. There will usually be a presence of mucus around the nares, or if not, this can usually be expressed by exerting gentle pressure over the bridge of the beak between the nostrils. Submaxiallary oedema and dark stains aorund the eye and nostril are often present. Altered vocalisation will occur later on in the course of the infection and behaviousla changes will be seen such as a hgeneralised depression- huddling, decreased activity and reduced appetite.
Diagnosis
Diagnosis is currently made by clinical signs and growth of the bacteria from a sample taken from the trachea of a sick or dead bird. It is recommended that the samples be taken early in the disease process to avoid other oppurtunistic bacteria colonising the trachea. Boredtella will take around 48 hours to grow on MacConkey agar.
A post mortem to identify lesions in upper respiratory tract, such as generalised softening and dorso-ventral compression of the trachea, plus presence of a mucoid substance, will also strengthen the diagnosis.
Serolgy can be performed in the form of an ELISA.
Control and Treatment
The administration of antibiotics has proved to have little effect in an outbreak of the disease.
Vaccination with dead or live vaccines to young turkeys and to breeder hens has been tested but is not commonly used.
Husbandry is the main way of preventing the disease, with adequate ventilation and decresed stress. Removal of dirty litter and thorough disinfection should be carried out after every depopulation.
References
Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial
Jordan, F, Pattison, M, Alexander, D, Faragher, T (1999) Poultry Diseases (Fifth edition) W.B. Saunders
Saif, Y.M, (2008) Diseases of Poultry (Twelfth edition) Blackwell Publishing