Canine Infectious Respiratory Disease (CIRD) - Kennel Cough

Flashcards covering aetiology, transmission, pathophysiology, clinical signs, diagnosis, treatment, and vaccination protocols for Canine Infectious Respiratory Disease (Kennel Cough).

What is Canine Infectious Respiratory Disease (CIRD) commonly known as?

Kennel Cough

What does it mean that CIRD has a multifactorial aetiology?

It is a clinical syndrome rarely caused by a single pathogen; instead, several viral and bacterial pathogens act sequentially or synergistically to produce disease.

Which host factors and environmental conditions contribute to the expression of CIRD?

Host factors include stress and immune status; environmental conditions include overcrowding and poor ventilation.

Which four pathogens are listed as common aetiological agents of CIRD?

Bordetella bronchiseptica, Canine Parainfluenza, Canine Adenovirus 2, and Canine Herpes Virus 1.

Which pathogens are classified as uncommon aetiological agents of CIRD?

Mycoplasma cynos, Canine Distemper Virus, Canine Respiratory Virus, Canine Respiratory Corona Virus, and Canine Influenza Virus.

Which three pathogens are included in the core vaccination schedule for dogs in Singapore?

Canine Adenovirus 2 (CAV2), Canine Parvovirus (CPV), and Canine Distemper Virus (CDV).

Why is the Rabies virus excluded from the core vaccination schedule for dogs in Singapore?

Because Singapore is rabies free.

Why is Canine Parvovirus (CPV) not an aetiological agent of CIRD, and what pathology does it cause instead?

Canine Parvovirus does not cause respiratory disease; instead, it causes severe haemorrhagic gastroenteritis, which is often fatal in dogs.

By what primary route are CIRD pathogens transmitted between animals?

Oronasal exposure through direct contact with virus-contaminated respiratory secretions (such as inhalation of respiratory droplets from coughing or sneezing) or environmental fomites.

What are fomites, and what examples can transmit CIRD pathogens?

Objects or materials that are likely to carry infection, such as clothes, shoes, utensils, and feeding equipment.

For how long after exposure do dogs pose an infectious risk, and how long must they be isolated from unexposed dogs?

Exposed dogs pose an infectious risk for up to $7\text{--}10\text{ days}$ and should be isolated from unexposed dogs for at least two full weeks.

What two key epithelial cell types line the trachea as shown in this diagram?

Pseudostratified ciliated columnar epithelial cells and mucus-secreting goblet cells.

What are the two primary functions of mucus secreted by tracheal goblet cells?

1. Protection against shear stress and chemical damage.
2. Trapping and elimination of particulate matter and microorganisms.

What is mucociliary clearance (MCC) and how does it protect the respiratory tract?

It is an innate defense mechanism of the lung where cilia on pseudostratified columnar epithelial cells beat in synchrony to propel mucus-trapped pathogens and particles out of the airways.

How does initial viral infection lead to secondary bacterial invasion in CIRD pathophysiology?

Viral replication in ciliated epithelial cells causes loss of coordinated ciliary beating, ciliostasis, and ciliated cell destruction. This renders mucociliary clearance ineffective, allowing secondary bacteria to colonize.

What two pathogenic mechanisms are caused by toxins produced by Bordetella bronchiseptica?

Tracheal toxins produce ciliostasis, and additional toxins inhibit the function of neutrophils.

During tracheal repair following CIRD damage, which cells initially divide to replace lost ciliated cells while stem cells differentiate?

Goblet cells initially divide to replace the damaged ciliated cells because stem cells require time to differentiate into ciliated epithelium.

What does the characteristic cough of CIRD sound like, and what do owners commonly mistake it for?

A harsh, loud, hacking cough (often described as sounding like something is stuck in the dog's throat), which owners frequently mistake for vomiting.

What characteristic finding is elicited on physical examination during tracheal palpation in a dog with CIRD?

The trachea is sensitive, and tracheal palpation easily elicits a cough.

How do demeanour, body temperature, and nasal discharge differ between uncomplicated and complicated CIRD?

Uncomplicated CIRD: alert and bright, afebrile, and absent mucopurulent discharge. Complicated CIRD: lethargic and depressed, pyrexia (fever) present, and mucopurulent nasal discharge present.

What is the typical duration of uncomplicated CIRD compared to complicated CIRD?

Uncomplicated CIRD lasts $7\text{--}14\text{ days}$, whereas complicated CIRD lasts $> 14\text{ days}$.

Which pathogens are typically associated with uncomplicated versus complicated CIRD?

Uncomplicated CIRD: Parainfluenza virus or Canine Adenovirus type 2 combined with Bordetella bronchiseptica. Complicated CIRD: Canine Distemper Virus, Mycoplasma species, or Canine Influenza Virus.

Why is routine antibacterial therapy considered controversial in uncomplicated CIRD?

Because Bordetella and Mycoplasma are frequently present in healthy dogs.

What supportive care instructions should be given to owners of a dog with uncomplicated CIRD?

Provide nutritious food and good nursing care to hasten recovery, and avoid excitement, exercise, and the use of neck collars.

What is the clinical role of nebulisation in managing CIRD?

It aerosolizes medications (saline, antibiotics, bronchodilators) into a fine mist inhaled via face mask to help loosen excessive accumulation of bronchial and tracheal secretions.

What route of administration is shown, and what immune advantages does it provide?

Intranasal vaccination; it stimulates mucosal immunity directly at the primary site of infection as well as systemic immunity.

What is the typical volume of vaccine administered via the intranasal route in dogs?

$0.5\,cm^3\text{ to } 1\,cm^3$ ($0.5\text{ ml to } 1\text{ ml}$).

How does the onset of protective immunity compare between intranasal and parenteral CIRD vaccines?

Intranasal vaccination confers protective immunity as early as $48\text{ to }72\text{ hr}$ after a single dose; parenteral vaccination requires $5\text{ to }7\text{ days}$ after administration of the second dose.

What is the initial vaccination schedule for puppies ($\le 16\text{ weeks}$ of age) receiving parenteral versus intranasal Bordetella vaccines?

Parenteral: two initial doses, $2\text{ to }4\text{ weeks}$ apart, beginning as early as $6\text{ to }8\text{ weeks}$ of age. Intranasal: a single dose administered between $8\text{ and }16\text{ weeks}$ (can be given as early as $3\text{ to }4\text{ weeks}$).

How long prior to kennel boarding should a dog be fully vaccinated against CIRD, and how effective is the vaccine?

Dogs should be fully vaccinated at least $7\text{ days}$ before boarding. Vaccines are not $100\%$ effective at preventing infection, but they modify or lessen disease severity if infection develops.