Infectious Tracheobronchitis of Dogs

Kennel cough is caused by inflammation of the upper airways. Although typically a mild, self-limiting disease, it can progress to fatal bronchopneumonia particularly in young dogs or to chronic bronchitis in debilitated older or geriatric dogs.

Aetiology: Canine parainfluenza virus, adenovirus 2 (CAV-1 and 2), distemper virus, reoviruses (1, 2, and 3), herpesvirus, and Bordetella bronchiseptica are implicated in teh aetiology of the ailment. Bordetella bronchiseptica and some gram-negative bacteria like Pseudomonas spp., Escherichia coli and Klebsiella pneumoniae) can cause secondary infections following viral injury of the respiratory tract. Mycoplasma spp. may also have a role inteh ailment. Susceptibility is elevated by stress and extremes of ventilation, temperature, and humidity.

Clinical Findings: Characteristic clinical sign are: paroxysms of harsh, dry coughing followed by retching and gagging. Affected dogs show also show partial anorexia. This condition can be complicated by secondary systemic infection to elicit more clinical signs including: fever, purulent nasal discharge, depression, anorexia, and a productive cough. Adverse environmental conditions and improper nutrition can contribute to a relapse.

Diagnosis: Kennel cough is suspected when the characteristic cough suddenly develops 5-10 days after exposure to other susceptible or affected dogs. Severity usually diminishes during the first 5 days although the ailment persists for up to 20 days. A similar condition can be induced by tracheal trauma secondary to intubation.

Treatment: dogs affected with this highly contagious but self-limiting disease should not be hospitalized! Management practices like good nutrition, hygiene, and nursing care and correction of predisposing environmental factors improve recovery. Codeine derivative-containig cough suppressants must be used when needed to control persistent non-productive coughing. Antibiotics selected by culture and sensitivity tests are only required in severe chronic cases. THese can be administered by aerosolisation treatment or endotracheal injection.

Prevention: Immunisation with modified live virus vaccines against distemper, parainfluenza, and CAV-2 also protects against CAV-1. There may be combinations of these with modified live parvovirus and leptospiral antigens as well. The initial vaccination is at 6-8 weeks of age. It is repreated twice at 3- to 4-week intervals until the dog is 14-16 weeks old. This is then followed by annual re-vaccination. Live, avirulent, intranasal vaccine is preferred to parenteral products with inactivated bacteria or bacterial extracts when the risk of B. bronchiseptica infection is significant.