Infectious Respiratory Disease of the Dog

Question 1

Causes of respiratory disease in the dog…

Answer 1

1. Kennel cough complex (Tracheobronchitis/CIRD)
2. Canine Distemper Virus
3. Canine Influenza Virus
4. Streptococcus equi zooepidemicus

Question 2

Aeitology of kennel cough..

Answer 2

Involves several infectious agents

• Canine parainfluenza virus
• Canine adenovirus type 2
• Bordetella bronchiseptica

Question 3

Describe Bordetella bronchiseptica as a pathogen…

Answer 3

Primary respiratory pathogen
Found as commensal in dogs respiratory tract
Needs initial damage to respiratory tract to cause disease
Attaches to cilia in the URT
Release of bacterial toxins damages respiratory epithelium and MCE

Question 4

Describe canine parainfluenza virus as a pathogen…

Answer 4

Mild respiratory disease
Frequently isolated from dogs with resp disease
More severe if in combination with Bordetella

Question 5

Describe canine adenovirus as a pathogen…

Answer 5

Type 2 causes respiratory disease
Not commonly associated with kennel cough in the UK
Type 1 causes hepatitis

Question 6

What other pathogens are associated with canine infectious respiratory disease apart from bordetella bronchiseptica, canine parainfluenza and canine adenovirus?

Answer 6

Canine herpesvirus 1
Canine resp coronavirus
Mycoplasma
Canine pnuemovirus

Question 7

Describe canine herpesvirus as a pathogen…

Answer 7

Systemic and often fatal disease in neonatal puppies (under 3 days)
Replicates best at lower body temperature
Isolated from adult dogs with respiratory disease

Question 8

Describe canine resp coronavirus as a pathogen…

Answer 8

Mild resp disease
Highly contagious
Vaccine under development
Not the same as enteric corona!

Question 9

Describe mycoplasma as a pathogen in dogs…

Answer 9

Mycoplasma cynos associated with resp disease

Other species found in the healthy dog.

Question 10

Epidemiology of chronic infectious respiratory disease (kennel cough)

Answer 10

Common in dogs housed in groups
Very contagious
Transmission by aerosol/droplets

Question 11

Pathogenesis of kennel cough

Answer 11

1. Infection of respiratory epithelial calls by virus or Bordetella
2. Cell damage caused by viruses and bacterial toxins
3. Inhibition of ciliary clearance by damage to ciliated cells
4. Secondary bacterial infection (strep, pasteurella)
5. Different mix of infectious agents may produce some clinical signs

Question 12

Clinical signs of kennel cough

Answer 12

3-7 days after exposure
Cough (dry or productive)
Retching
Nasal +/- ocular discharge
Sneezing
Most recover after 1-3 weeks

Question 13

Systemic disease associated with CIRD…

Answer 13

Depression, pyrexia and inappetence
Progression to bronchopenumonia cause by secondary bacterial infection
Canine distemper virus
Strep equi zooepidemicus

Question 14

When are diagnostics tests necessary for CIRD?

Answer 14

When no improvement after two weeks or signs of systemic disease

Question 15

What are the diagnostics tests are available for CIRD?

Answer 15

Bacterial isolation 
Viral isolation or PCR
Serology
Faecal smear
Haematology

Question 16

Treatment for CIRD?

Answer 16

Rest
Cough suppressants
Bronchodilators
Mucolytics
Supportive care

Question 17

Prevention and control for CIRD?

Answer 17

Vaccines

- B. bronchiseptica, parainfluenza and adenovirus

Question 18

Husbandry measures to control CIRD spread?

Answer 18

Isolation of infected animals
Cleaning kennels, bowls
Good ventilation
Isolation of newcomers

Question 19

Describe canine distemper virus

Answer 19

Morbillivruis
Sheds in all body fluids
Spreads by aerosol or close contact
Fatal on it’s own

Question 20

Pathogenesis of canine distemper virus…

Answer 20

1. Virus enters via respiratory tract
2. Spreads to tonsils and local lymph nodes
3. Infects monocytes/macrophages
4. Viraemia, systemic dissemination
5. 2-3 weeks after infection, those which develop good humoral and cellular response will recover
6. Insufficient immune response = spreads to epithelial cells of respiratory, GI, gentitourinary tract and CNS
7. Kills by secondary bacterial infection (interstitial pneumonia usually)

Question 21

Clinical signs of canine distemper virus?

Answer 21

Nasal and ocular discharge
Cough
Diarrhoea
Vomiting
Depression
Anorexia

Question 22

What are the CNS signs associated with canine distemper?

Answer 22

Seizures, incoordination, paresis, muscle tremors, ocular lesions
Demyelination

Question 23

What is seen in chronic canine distemper?

Answer 23

Hyperkeratosis of foot pads and nose
Distemper teeth (hypoplasia of enamel)

Question 24

How do you diagnose canine distemper?

Answer 24

Clinical signs and history
Haematology - lymphopenia
Serology - IgM
Virus isolation/PCR
Immunofluorescence

Question 25

What is the treatment for canine distemper?

Answer 25

Antibiotics to prevent secondary infection Fluid therapy Sedatives CNS signs may improve with time

Question 26

Prevention and control of canine distemper?

Answer 26

``` Live attenuated vaccines 8 weeks, 10-12 weeks, 1 year Boosters every 2 Isolation Disinfection ```

Question 27

Describe influenza virus in dogs...

Answer 27

Some develop mild respiratory disease | Some haemorrhagic pneumonia

Question 28

Describe streptococci in dogs...

Answer 28

``` Found in the normal respiratory tract Secondary damage to lungs Severe necro-haemorrhagic and fibrino-suppurative bronchopneumonia Diagnosis by lung samples and swabs Treatment - IV fluid, ABs High mortality Zoonosis ```