KC

• Kennel cough has been renamed to Canine Infectious Respiratory Disease Complex (CIRD or CIRDc)
• Kennel cough is often mild/moderate but occasionally severe/ fatal. The common clinical presentation includes…

  • Hacking cough which may or may not be productive
  • Some clients see a productive cough as V+
  • Submandibular lymphadenopathy
  • Ocular/ nasal discharge
  • Possible lethargy
  • Possible pyrexia
• what is the difference between DNA and RNA viruses? why does it matter?

  • DNA virus' can encode up to a hundred viral proteins
  • RNA viruses have smaller genomes and usually encode only a few proteins

  RNA viruses are less stable and more prone to mutation so they generally change and evolve faster, this can make it harder to treat and can also jump from species to species
• what is the significance of a viral envelope?

  a viral envelope provides better protection from the hosts immune system, enzymes and certain chemicals. Hence, enveloped viruses are more hardy so are better at surviving in the body and environment
• Diseases that can cause kennel cough are...

  • Canine parainfluenza virus
  • This is an enveloped RNA virus which only affects the upper respiratory tract only
  • This can be prevented by subcutaneous and intranasal vaccines
  • Canine adenovirus-2
  • This is a non-enveloped DNA virus which is closely related to CAV-1 (infectious canine hepatitis)
  • The vaccine for this agent is based on CAV-2 and protects against both pathogens. This vaccine is part of the “core” vaccine schedule
  • Canine respiratory coronavirus
  • This is an enveloped RNA virus
  • Bordetella bronchiseptica
• Bordetella bronchiseptica is a gram negative aerobic, coccobacillus bacterium which can be a primary or secondary problem

  • This disease it causes can vary from mild to severe and spreads between dogs, humans and cats. (zoonotic potential). This bacterium can be carried by rats, guinea pigs and rabbits with no clinical signs.
  • Shedding post-infection occurs up to 12 weeks (which is important to remember, be sure to ask about immunocompromised individuals)
• Canine Distemper Virus It is an enveloped RNA virus that is shed in all body fluids

  • It causes severe disease including, purulent ocular and nasal discharge, haemorrhagic vomiting and diarrhoea, neurological signs and hyperkeratosis “hard pad”
  • rarely a cause of kennel cough
• Canine influenza is an uncommon cause of kennel cough in the UK. Infected dogs are often infectious without having clinical signs.

  • This causes a cough, and purulent nasal discharge which lasts for 10 to 30 days. About 20% of cases become very unwell and develop pyrexia and pneumonia
• Strep equi has a high morbidity (90%) and a high mortality (50%). It causes pyrexia, bloody nasal discharge and haematemesis (severe broncho-pneumonias)

  • rarely causes KC
• Transmission is mainly by aerosols (smaller the particle the longer they can stay in the air and the easier it is for them to enter the lungs) but some direct transmission is possible

  • CAV and Bordetella are environmentally labile
• Diagnostic options include…

  • Paired serology (looking at antibody titres)
  • Nasal or oropharyngeal swab for most pathogens (PCR)
  • Conjunctival swab for distemper (contact the lab if suspicious of distemper)
• Symptomatic treatment include: avoiding choke chains/pulling on collar, cleaning the eyes and nose, NSAIDS to reduce pyrexia (but not ideal treatment choice), paracetamol (better anti-pyrectic agent), butorphanol, codeine and glycerine. Antibiotics are not always necessary to treat KC as most cases are viral in origin.
• Pneumonia can develop following initial URT disease

  • Cough (depending on location, broncho pneumonias cough)
  • Dyspnoea/tachypnoea
  • May have marked pyrexia (not always)

  This may become life threatening very quickly
• If Bordetella is suspected the antibiotic must have gram negative cover.

  • Secondary pathogens usually gram negative – Pseudomonas, Klebsiella but may be gram positive
  • Tetracyclines (doxycycline), potentiated sulphonamides and potentiated amoxycillin is best
• do animals with pneumonia cough?

  Some. There are no cough receptors in the alveoli so if the pneumonia is deep enough they will not cough
• Why dont you use NSAIDs to treat a cough?

  NSAIDs also do not act on the cough receptors so are unable to repress signals in the cough reflex arc. When you use NSAIDS you can still get some of the swelling as they are acting lower down, however if you used steroids you reduce arachidonic acid production reducing the swelling, redness, itchiness etc.

  Prostaglandins aid with bronchodilation and is protective to the lungs hence NSAIDs are contraindicated.
• To prevent KC: maintain environmental hygiene, reduce dog-to-dog contact, reduce fomite transmission, improve ventilation and implement vaccination strategies.
• he respiratory vaccines used include..

  • Parainfluenza – live, subcutaneous OR intranasal (combined with Bordetella).
  • Distemper – live, subcutaneous.
• Protective immunity = pathogen replication is limited before the disease symptoms develop or only cause a mild disease
• Amoxicillin doesn’t penetrate well into the bronchus but doxycycline does.