Cause
The disease is caused by Bordetella bronchiseptica , a gram-negative bacterium
which inhabits the upper respiratory tract, but is associated with both upper
and lower airway disease, including pneumonia. Often other respiratory
infectious agents are present at the same time (e.g. viral - e.g. canine
distemper virus, canine adenoviruses 1 and 2 , canine parainfluenza virus or
canine herpes virus - or mycoplasma infections). The organism is resistant in
the environment surviving some 3 weeks in water
Signs
The clinical signs are of a cough with varying degrees of difficulty in
breathing which depends upon the severity of the infection. Bronchopneumonia
with complications can lead to death.
Dogs : Bordetella bronchiseptica is the most common bacterial agent
associated with tracheobronchitis (known as "kennel cough") in dogs.
Disease outbreaks frequently occur during the summer vacations and at other
times when dogs are kenneled away from home, come into contact with infected
carriers, and then spread it around their neighbourhood when they come out.
The typical acute onset cough sounds like a "honk" to owners who
often think the dog has something stuck in it's throat. Sometimes there is a
nasal discharge and mucus may be coughed up - which can be confused for retching
or vomiting.
Cats : Bordetella bronchiseptica is a significant cause of pneumonia
and mortality in cats and kittens (especially when kept in colonies)
Guinea pigs : Bordetella bronchiseptica is the most common bacteria
causing respiratory disease in guinea pigs. It results in abnormal respiratory
sounds, sneezing, a nasal discharge, inappetance, depression, weight loss and in
severe cases death.
Diagnosis
Presenting history . No vaccination history.
Transtracheal aspiration of fluid - identify neutrophils in exudate and
bacterial culture. Culture of swabs taken from the mouth, throat or upper airway
are not reliable.
X-rays may be helpful if there are signs of pulmonary damage -
hyperinflation, atelectasis, consolidation of lung lobes.
Prevention
Dogs : Intranasal vaccinations are reasonably effective with few
side-effects, although some dogs develop a cough a few days after vaccination.
The vaccine produces local immunity and for this reason maternal antibody does
not interfere with it. Therefore puppies as young as 2 weeks of age can be given
the vaccination if they are likely to come into contact with dogs with the
disease (such as in a boarding kennel environment). Because immunity takes 5
days to develop following the vaccine administration dogs should be dosed a week
before they are likely to be exposed to the infection. For routine prevention
the vaccine should be administered every 6 months.
Guinea pigs : Use of pig B.bronchiseptica vaccine and the use of an
autogenous vaccine have both been tried in guinea pigs - with success.
Unfortunately vaccinated animals become carriers of the infection.
Treatment
Dogs : Antibiotics may reduce the duration of the illness. Use amoxicillin
clavanulate - 12.5-25 mg/kg body weight by mouth every 12 hours for 14 days. OR
Trimethoprim-sulphonamide combination at 15mg/kg body weight by mouth every 12
hours for 14 days. Glucocorticoids may reduce the cough - prednisolone at
0.25-0.5mg/kg by mouth every 12 hours for 3-5 days. Aerosol therapy is sometimes
helpful in cases with severe bronchial fluid accumulation - 6-10ml sterile
saline nebulized over 15-20 minutes 1-4 times a day with the oxygen administered
at 3-5L/min.
Guinea pigs : Therapy is often unsuccessful even when started early. Broad
spectrum antibiotics are otherwise indicated e.g. chloramphenicol 20mg/kg body
weight intramuscularly twice a day, OR chloramphenicol 50mg/kg body weight three
times daily by mouth. Unfortunately animals that survive the acute stages become
carriers of the infection