Download Kennel cough

To
The Irish Leonberger Club
From
Antonella Puggioni DVM, CertVDI, DipECVDI
European Veterinary Specialist in Diagnostic Imaging
Lecturer In Veterinary Diagnostic Imaging
University Veterinary Hospital
Subject
Kennel Cough
Date
November 2007
_______________________________________________________________________
Kennel cough
Definition: “Kennel cough” is the “familiar” term referring to a relatively
common pathology of the respiratory tract (the trachea and bronchi) that is also
and more appropriately called Infectious tracheobronchitis. The term kennel
cough originated by the fact that this is a pathology, as often happens with
highly contagious respiratory diseases, that spreads more easily and extremely
quickly when there are several dogs confined together in a populated, enclosed
environment such as that of a kennel.
In reality dogs can become infected without having been in a kennel, but just for
having been in contact with an infected dog.
Etiology: Kennel cough has to be considered a complex infection as there are
several micro-organisms that “work” together to cause the pathology, as
opposed to having only one etiologic agent as the cause.
The main component of this group of pathogens is Bordetella Bronchiseptica, a
bacterium that accounts for 80-90% of the cases of kennel cough. However,
most times there are concurrent viral infections and the two most common
viruses involved are Adenovirus and parainfluenza virus and in fact Bordetella
infection is considered a complication of the viral infection.
The pathology is highly contagious due to the fact that the pathogens are
airborne with dust and small particles and when dogs are closed together are
easily spread amongst them by inhalation.
Pathogenesis: The whole respiratory tract is lined by a thin layer of microvilli,
that with with the aid of the mucous normally present in healthy animals, keep
the tract free of pathogens and other particles that could cause a reaction. When
the microvilli are not working properly due to arrival of aggressive pathogens,
changes in temperature or even congenital deficiencies in the villi structure, the
delicate balance of the environment of the respiratory tract is altered and the
microvillous lining becomes an ideal environment for replication of inhaled
organisms, thereby leading to the onset of the clinical signs of the infections.
Clinical signs: The clinical signs of uncomplicated infectious tracheobronchitis
are usually mild. The typical clinical sign is a dry, non-productive, harsh cough,
that almost sounds like retching or like the dog has something stuck in its throat;
the cough may be elicited by exercise. The animal is otherwise in good form in
the initial and mild stages, eating and exercising normally. Complications may
include the development of fever, and in more rare cases, pneumonia.
The incubation period varies depending on the agent, from 3 up to 10 days. The
clinical signs last about 7 to 21 days.
An affected dog can keep spreading the infection for up to 14 weeks even after it
becomes asymptomatic.
Treatment: The common treatment for kennel cough is a symptomatic therapy
to suppress the cough, but is it essential that anti-tussive (anti-cough) agents
are not used if the cough is productive. Antibiotics are often added when
Bordetella infection is suspected, or signs consistent with secondary bacterial
complications are present (e.g. fever or a purulent nasal discharge). Either way,
the owner should not discard the condition as an insignificant one and try to
treat the animal without seeking the expertise of a veterinarian.
Prevention: Kennel cough can be prevented up to a certain point with the use
of vaccines.
Two main types are available: intranasal and intramuscular formulations. The
intranasal one assures a quicker immune response (within 4-5 days). Although
the intramuscular injection requires more time to be effective, it has been
suggested that the immunity may last longer. The downside is that the
commonly used vaccines are only active against Bordetella bronchiseptica and
Parainfluenza 3 virus, and not all the other components of the syndrome.
Animals that have been infected have some immunity; however, the duration of
such immunity is hard to establish.