Canine Infectious Diseases Flashcards
What cells are targeted by parvovirus?
Rapidly dividing GI cells esp. crypt epithelial cells, causing villus blunting
Villus blunting by parvovirus leads to?
Decreased absorption (diarrhoea), necrosis (sloughing + blood), and inflammation. Lack of GI integrity can lead to bacteraemia + sepsis
What disinfectant is parvovirus susceptible to?
Bleach
Vertical (in-utero) infection with parvovirus causes what illness in puppies?
Myocarditis
Describe the typical transmission of parvovirus
Horizontal - oronasal/faecal - virus enters oronasal cavity -> infects lymphoid tissue -> then viraemia for 1-5 days
What factors impact the severity of parvovirus infection?
Virulence of strain
Size of inoculum
Host defences
Age (young = higher risk)
Breed (Rottweilers, Dobermanns, American Pit Bulls)
When is parvovirus typically shed in faeces?
3-14 days post-infection
When is the clinical disease of parvovirus typically present?
5-12 days post-infection
What are the clinical signs of parvovirus?
Foul smelling, bloody diarrhoea
Vomiting
Leukopenia
Fever
May develop sepsis, then DIC
A dog has acute vomiting and diarrhoea, what should you always screen for prior to admission?
Parvovirus
How would you diagnose parvovirus?
Clinical signs/History (often young, incomplete vaccination)
Detection of faecal antigen with ELISA or PCR
Compare the advantages/disadvantages of PCR and ELISA tests for parvovirus
ELISA:
A - in house, inexpensive, quick
D - specific but poorly sensitive (false negative possible)
PCR:
A - definitive diagnosis
D - lab test (wait time)
What is the goal when treating parvovirus?
Restore fluid + electrolyte balance, avoid sepsis
Outline a typical treatment plan for parvovirus
ISOLATION
IV fluids - correct dehydration + monitor electrolytes
IV aminopenicillins - treat “leaky gut”, protect from bacteraemia
Anti-emetics - maropitant
NG or NO tube - “feed gut”
Monitor for:
Hypokalaemia, hypoglycaemia, hypoalbuminaemia, anaemia, intussusception (palpate daily)
What organisms are responsible for Canine Infectious Respiratory Disease Complex (CIRDC)?
Viral:
Canine Parainfluenza Virus
Bacterial:
Bordetella bronchiseptica
Mycoplasma spp.
CIRDC has HIGH ______ and LOW ______
CIRDC has HIGH morbidity and LOW mortality
How is CIRDC transmitted?
Respiratory secretions
Vaccines for CIRDC …..
Do not prevent infection, but should reduce severity of clinical signs
What are the clinical signs of CIRDC?
Paroxysmal cough with terminal retch
Fever, anorexia, lethargy
SMLN enlarged
Erythematous oropharynx
“tracheal pinch” induced cough
A dog that has been in kennels or to the park recently presents with a mild cough, thoracic auscultation is normal and the dog appears well. How will you treat?
Rest, isolate from other dogs, provide soft food
AB NOT JUSTIFIED
A dog that has been in kennels recently returns to you after 7 days of persistent, non-productive coughing. How will you treat it?
AB: Doxycycline for 7-10 days
+/- Antitussives e.g. hydrocodone (NOT if cough is productive)
Continue rest + isolation from other dogs
What must you do if you diagnose Ehrlichia canis?
Notify DPIRD
What is Ehrlichia canis, and how is it transmitted?
Bacterial infection transmitted by Brown Dog Tick (Rhipicephalus sanguineus)
What does Ehrlichia canis cause and what clinical signs occur?
Acute reduction in red blood cells (esp. platelets)
CS: fever, lethargy, thrombocytopenia, myalgia, anorexia, lymphadenopathy, petechia
How do you definitively diagnose Ehrlichia canis?
PCR (DPIRD funded) or serological antibodies
What in house tests help diagnose Ehrlichia canis?
Platelet count, PCV, buccal mucosal bleeding time (BMBT)
How do you treat Ehrlichia canis?
Doxycycline for 28 days
5mg/kg PO q12hr
OR
10mg/kg PO q24hr
A client is worried about Ehrlichia canis, what advice will you give to them?
Tick prevention is key! Regular prophylaxis or tick collars
Check dogs for ticks at every bath
Explain geographical distribution (mostly Northern Aus - but this may change w/ time)
You are working in NSW and a farm dog presents with non-specific lethargy, vomiting and diarrhoea. What disease should be included as a DDx?
Leptospirosis
What questions may help if you suspect leptospirosis?
Is there any contact with rats?
Any contact with stagnant water (i.e. dams, ponds)?
What area is the animal from?
Has there been any travel recently to an area which has has reported cases?
What are the clinical signs of Heartworm disease?
Coughing, exercise intolerance, weight loss, abdominal distension, lethargy
What do heartworm antigen tests detect?
Proteins from adult female D. immitis (>6 months post-infection)
What does a modified Knott test detect?
Circulating microfilariea of D. immitis (>6-7 months post-infection)
If a dog has lapsed prophylaxis for heartworm, what must you do before recommencing prophylaxis?
Ensure no circulating microfilariea - perform modified Knott test
What would your heartworm prophylaxis protocol be for a dog aged 2-7 months?
Start prophylaxis, but test for antigen and microfilariea 6 months later
What would your heartworm prophylaxis protocol be for a dog older than 7 months?
Test for antigen and microfilariea prior to starting prophylaxis, if clear start prophylaxis and test again 6 months later
Why should you never start heartworm prophylaxis without testing?
Sudden death of adult worms and microfilariea may result in thromboembolism leading to sudden death, or cause transient shock-like hypersensitivity
A dog returns a positive heartworm antigen test, what is your next step?
Must confirm positive result - repeat antigen test (different brand)
And perform Knott’s test to determine microfilariea presence
You have confirmed a positive heartworm antigen result in a dog, but there are no microfilariea present and the dog is clinically well. What is your next step?
Commence prophylaxis
A dog is heartworm antigen negative but microfilariea positive. What is your next step?
Do not start prophylaxis - risk of shock.
Must identify microfilariea (may be Dipetalonema)
