Canine Infectious Tracheobronchitis

Canine Infecious tracheobronchitis

Also known as:

Kennel Cough Canine respiratory disease complex

Description

A highly contagious acute respiratory disease spread by close contact causing larngitis, tracheitis, bronchitis and in some cases a rhinitis. Multiple agents are implicated in the disease including Canine Adenovirus 1 ,Canine Adenovirus 2,Canine herpes virus,Canine Parainfluenza - 2,Canine Distemper Virus, and Bordetella bronchoseptica. Very common disease in dogs that are housed in groups.

Signalment

Affects dogs of all ages. Puppies and immunocompromised dogs are often worst affected.

History and Clinical Signs

Often a history of exposure to other dogs at either rehoming centers, bording kennels, or in a hospital etc. Direct contact or aerosol spread are the most common routes of infection. Clinical signs develop 3-5 days after exposure. Signs are often mild and self limiting. Afected dogs usually have a dry hacking cough which is likely to be exacerbated on exercise or excitement. Sometimes sneezing, serous nasal discharge and lymphadenopathy are present. The clinical signs typically persist for 2-3 days to 2-3 weeks.

Systemic signs are likely to indicate the development of bronchopneumonia, signs include pyrexia, inappetance and depression. Systemic disease is more likely to occur in young or immunocompromised animals. This condition is usually a result of secondary infection with and.

Diagnosis is most often made on history and physical exam ruling out other causes of the cough.

Laboratory Tests

Haematology and Biochemistry will help to look for an underlying cause of disease in immunocomprommised animals. Additionally they may show signs of infection including a Neutrophiliasometimes with a left shft.

Radiography

Thoracic radiography and ultrasound are often unremarkable however may help to rule out other causes of the cough.

Endoscopy

Only considered when it is necessary to rule out a number of alternative diagnoses. Will enable collection of samples from the respiratory tract. Often no specific findings however, tracheal cytology which may reveal inreased numbers of neutrophils and bacteria. Samples for bacteriology from the upper airways may be deceptive as they are likely to harbour many commensal organisms. Ideally samples sholud be collected from the lower airways by a transbronchial wash.

Treatment

Uncomplicated cases are often self limiting and will resolve with or without treatment. Antibiotic treatment is indicated if the animal is showing signs of systemic illness or if there is bronchopneumonia present. Where culture and sensitivity has been undertaken an appropriate antibiotic should be chosen on the results otherwise doxycycline, erythromycin, chloramphenicol or a potentiated sulphonamide are good choices. Antitussives and bronchodilators may be used to alleviate severe coughing. Nebulization can also be useful to help loosen bronchial and tracheal secretions. In patients with severe disease further supportive care including fluids and enteral feeding wil be required. Anti-inflammatories may help relieve some of the clinical signs however there use is contra-indicated in immunocompromised animals.

Control

Vaccines can prevent or reduce the severity of disease caused by B. bronchiseptica, parainfluenza virus and adenovirus. Vaccinated animals can still contract the disease as multiple agents are implicated. Vaccines are available to be given systemically or intranasally. Intranasal vaccination provides mucosal IgA immunity and the presence of maternal antibodies are not a problem. It is important to practice good husbandry in areas where groups of dogs mix. Ideally all animals should be vaccinated, any infected animals should be isolated to minimise the spread to unaffected animals and all fomites that have come into contact with an affected animal must be disinfected. Areas should be kept well ventilated and ideally animals should be kept in low population densities.

Prognosis

Good, generally self limiting.

References

Ettinger, S.J, Feldman, E.C. (2005) Textbook of Veterinary Internal Medicine (6th edition, volume 2)

Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial

• Synonyms: Kennel cough, Infectious tracheobronchitis
• tracheitis, bronchitis
• Multiple agents implicated:

• Symptoms are of a persistent, non-productive cough
• Persistent tracheobronchial inflammation
• The outcomes is generally recovery (may persist >3 weeks), but extension to chronic bronchitis or cranioventral bronchopneumonia may occur
• In severe cases can extend to serous/mucopurulent rhinitis
• Lesions are neither specific nor always significant (catarrhal / mucopurulent tracheobronchitis)
• Enlarged tonsils and retropharyngeal lymph nodes

• B. bronchiseptica acts as a primary pathogen in Infectious canine tracheitis
• Frequently isolated from dogs with respiratory disease
• Often found with viruses or mycoplasma
• Adheres to ciliated epithelial cells in the trachea
• Colonisation and proliferation in trachea
• Releases toxins causing epithelial necrosis and prevents ciliary clearance
• Irritation to tract causes coughing
• Mortality rates low
• Peribronchial inflammation and bronchopneumonia

can result in unvaccinated puppies or immunosuppressed dogs

• Severe pneumonia following secondary infection e.g. with Streptococci
• Fatal bronchopneumonia if occurs secondary to canine distemper virus
• Transmission via respiratory secretions by direct contact or aerosol and on fomites
• Clinical signs:
  • Develop within 3-4 days; persist for up to 2 weeks
  • Coughing
  • Gagging
  • Mild serous oculonasal discharge
• Treatments includes antibiotics if coughing persists or bronchopneumonia develops
• Live intranasal vaccines
• Also found in respiratory tract of cats; can cause pneumonia in kittens; vaccine available