Originally appeared as Ask the Vet by Dr. Shawn Ashley in Pug Talk Magazine (March/April)
Canine Infectious Tracheobroachitis or 'Kennel Cough' is a complex of organisms that affect the larynx, trachea, bronchi and occasionally the lower respiratory tree. Like colds in humans there are many agents that can cause kennel cough. These agents are not zoonotic and thus do not affect people.
Canine parainfluenza is the most common virus isolated and often acts in conjunction with the bacteria Bordetella bronchiseptica. Other agents include mycoplasmas, canine adenoviruses, and rarely canine berpesvirus and reoviruses. In severe cases of tracheobronchitis in which pneumonia develops, canine distemper virus must be ruled out. The primary agents of the Kennel Cough Complex - parainfluenza and bordetella - are highly contagious and can be spread from one dog to another by aerosol transmission. Possible sources of exposure are kennels, dog shows, grooming salons, and veterinary hospitals.
The organisms replicate in the cells lining the nasal passages and respiratory tree. Most infections are self limiting; however, other cases can lead to persistent coughing, sneezing and retching, with most severe cases leading to bronchopneumonia.
The incubation period from exposure to clinical signs is on average 3 - 7 days. The organisms attach to the respiratory tract lining and overcome the dog's local immune defense. The vocal cords become swollen, there is an increase in airway resistance which gives rise to a high pitch 'honk" during coughing. In uncomplicated forms of tracheobronchitis the dog has a dry, backing cough followed by retching or gagging.
Often owners see vomiting of mucus or may believe the dog has something caught in its throat. Complicated forms are those cases which develop a secondary bacterial infection.
Signs include a fever, purulent nasal and eye discharge, problems breathing, a decreased appetite. This is often seen in young animals or in circumstances that render the dog immune compromised (pregnancy, stress, demodectic mange, chronic disease).
Pugs and other brachycephalic breeds are prone to upper respiratory tract infections due to shortened nasal passages, elongated soft palates, improper nasal and ocular drainage, collapsing tracheas, and predisposition to atopy or hayfever. Therefore, treatment and prevention can become a chronic concern to the Pug Breeder.
Treatment of uncomplicated tracheobronchitis consists of simple medical regimens. Antibiotics are not necessary except only as prophylaxis toward a secondary bacterial infection. Cough suppressants can be used with mild unproductive coughs. Expectorants such as Robitussin should be utilized to loosen bronchiolar secretions in chronic hacking coughs.
If the cough persists more than a few days a veterinarian should be contacted. In complicated cases appropriate antibiotics should be administered for at least 14 days and some cases may need to be given up to six weeks. When pneumonia incurs supportive treatment must be implemented - fluid therapy vaporization/nebulization, and bronchodilators.
Ways to prevent Chronic Tracheobronchitis are through vaccination against the common causative agents distemper, adenoviruses, parainfluenza (DHLP) and bordetella bronchiseptica. Control allergies with antihistamines or antigen shots. If hacking due to tracheal irritation continues surgical intervention may be necessary to correct elongated soft palates, stenotic nasal passages, excessive nasal folds, periodontal gum disease or tonsillitis.
Blood work, x-rays, ekg's, bronchscopsy, and biopsies may be needed to rule out heart/lung or other disease processes causing persistent coughing. Persistent infections should be cultured by nose/throat swabs or by a tracheal wash.
Kennel Cough can in the end become a chronic problem with no cure, just a managing of the symptoms; therefore, it is highly recommended to stress prevention in your breeding pairs as well as your pets.