Lecture 7 -- Kennel cough

These flashcards cover key vocabulary and concepts related to respiratory infections in dogs, including causes, symptoms, and treatments.

What is “kennel cough”?

• Similar to the common cold in humans, affecting the upper respiratory tract

• Not a single disease, but a clinical syndrome

• Can caused by multiple viruses and bacteria

What are the common viruses that cause kennel cough (canine infectious respiratory disease complex, CIRDC)?

1. Canine parainfluenza virus (CPiV)

2. Canine adenovirus type 2 (CAV-2)

3. Canine herpesvirus

4. Canine influenza virus

5. Canine respiratory coronavirus

Which family does canine parainfluenza virus (CPiV) belong to? Which other canine virus belongs to the same family?

• Belongs to family paramyxoviridae (Genus - Respirovirus)

• Canine distemper virus also belongs to paramyxoviridae (but in different genus - morbilivirus)

What type of virus is canine parainfluenza virus (CPiV)?

Enveloped single stranded RNA virus

• Mutate easily

• Fragile in the environment

How does canine parainfluenza virus cause disease?

• Excreted in oronasal secretions

• Multiplies locally in epithelial and lymphoid cells of respiratory tract (NOT systemic)

• Causes mild cough and clear nasal discharge

Are vaccines available for CPiV? If so, what type of vaccine is used?

Yes

• Live attenuated vaccines

How does canine herpesvirus affect puppies less than 2 weeks?

Canine herpesvirus can generalise and cause fading puppy syndrome → High mortality

How does canine herpesvirus affect older puppies/ adults?

Virus is restricted to external mucous → Mild URT and genital tract infection → Clinical sign: Mild nasal serous discharge

How does equine influenza affect dogs?

H3N8 strain originally equine influenza → Antigenic shift → Can infect dogs = Canine influenza

What are the possible transmission routes of equine influenza to dogs?

Feeding raw horse meat contaminated with virus to dogs

What are the clinical signs of canine influenza?

• 80% mild kennel cough

  • Nasal discharge and cough (10-21days)

• 5-8% pneumonia and death

  • High fever, dyspnoea and lung consolidation

Are vaccines available for canine influenza H3N8? If so, what type of vaccines are used?

Yes

• Inactivated vaccines against canine influenza virus (H3N8) is available

What are the common bacteria that cause kennel cough (canine infectious respiratory disease complex, CIRDC)?

Bordetella bronchiseptica

What type of organism is Bordetella bronchiseptica?

Gram-negative smal coccobacillus

What is the incubation period of Bordetella bronchiseptica?

~6 days

How does Bordetella bronchiseptica cause disease (pathogenesis)?

• Attaches to ciliated respiratory epithelium

• Replicates and produces virulence factors

• Causes ciliostasis → stops cilia from beating → Impair mucociliary clearance → Compromise the ability to clear infection

What are the clinical signs of Bordetella bronchiseptica infection?

• Goose like honking cough

• Nasal discharge

• Bronchopneumonia

How is Bordetella bronchiseptica diagnosed?

• History and clinical signs

• Nasal/oropharyngeal swabs

• Transtracheal wash

• Bronchoalveolar lavage

• Culture on selective agar (charcoal 木炭 with antibiotics like cephalexin)

Why is cephalexin used in Bordetella bronchiseptica culture?

• Cephalexin can suppresse growth of other bacteria normally present in the dog’s nose and throat

• BUT since bordetella is resistant to cephalexin, so it can still grow on the medium

Why is PCR not routinely used to diagnose Bordetella bronchiseptica (Bb)?

Since bordetella bronchiseptica is a bacteria, instead of virus

How is Bordetella bronchiseptica treated?

• Systemic antibiotics if clinical signs persist >10 days or the dog is systemically unwell (BSAVA guidelines)

• Antitussives to reduce coughing

• Bronchodilators if needed

• Expectorants (e.g., bathroom with hot shower)

Can Bordetella bronchiseptica infect other species?

Yes. Cats in contact with infected dogs can become infected.

What vaccines are available against Bordetella bronchiseptica?

Avirulent live intranasal vaccine

How often should dogs be revaccinated for Bordetella bronchiseptica (Bb)?

Bordetella vaccines have a short duration of immunity → Annual revaccination

Is Bordetella bronchiseptica a zoonotic disease?

Yes, but rarely

• Infection of a human from a rabbit previously reported

How is Bordetella bronchiseptica controlled in kennels?

• Vaccinate dogs

• Isolate affected dogs

• Maintain good hygiene

• Prevent direct contact between animals

• Ensure adequate ventilation

• Keep stocking density low

Which fungi can cause nasal problems in dogs?

Aspergillus species

• Filamentous fungi, ubiquitous in soil, plant debris, and air

• Causes nasal aspergillosis

Which dogs are most susceptible to nasal aspergillosis?

• Young dogs

• Dolichocephalic breeds (long-nosed dogs)

• Dogs that are immunocompromised

What are the clinical signs of nasal aspergillosis ?

• Chronic nasal discharge

• Epistaxis

• Depigmentation of the nose

• Pain around the muzzle or on eating (due to bone erosion of nasal turbinates)

How is nasal aspergillosis diagnosed?

• Radiography / CT → Detect bone erosion in sinuses

• Serology → Detect antibodies against Aspergillus

• Fungal culture

• Direct examination / endoscopy → Visualisation of fungal plaques

• Exclusion of other causes of chronic nasal discharge

How is nasal aspergillosis treated?

• Systemic anti-fungals e.g. amphotericin B (belongs to polyene group)

• Flushing the nasal passages and sinuses with topical anti-fungal

P.S. Systemic anti-fungals often are no able to clear the infection alone → Need to use with topical anti-fungals

• Surgery (Remove affected turbinates)