Bordetella bronchiseptica is the most common bacteria isolated from this disease. Clinical signs of infections occur three to four days after exposure and, if uncomplicated with other agents, will last around 10 days. However after the infection has been resolved, the affected animal will continue to shed the bacteria for 6 to 14 weeks and can spread the disease to other susceptible animals during that time. Parainfluenza and Bordetella most commonly appear together in infectious tracheobronchitis, creating a disease that normally last from 14-20 days. The most common symptom is a dry hacking cough sometimes followed by retching.
Many owners describe the cough as having a honking sound .
A watery nasal discharge may also be present. With mild cases, dogs continue to eat and be alert and active. Many times there is a recent history of boarding or coming in contact with other dogs. In more severe case the symptoms may progress and include lethargy, fever, inappetence, pneumonia and in very severe cases even death. The majority of severe cases occur in immunocompromised animals, or young unvaccinated puppies.