Canine Infectious Diseases

Question 1

What cells are targeted by parvovirus?

Answer 1

Rapidly dividing GI cells esp. crypt epithelial cells, causing villus blunting

Question 2

Villus blunting by parvovirus leads to?

Answer 2

Decreased absorption (diarrhoea), necrosis (sloughing + blood), and inflammation. Lack of GI integrity can lead to bacteraemia + sepsis

Question 3

What disinfectant is parvovirus susceptible to?

Answer 3

Bleach

Question 4

Vertical (in-utero) infection with parvovirus causes what illness in puppies?

Answer 4

Myocarditis

Question 5

Describe the typical transmission of parvovirus

Answer 5

Horizontal - oronasal/faecal - virus enters oronasal cavity -> infects lymphoid tissue -> then viraemia for 1-5 days

Question 6

What factors impact the severity of parvovirus infection?

Answer 6

Virulence of strain
Size of inoculum
Host defences
Age (young = higher risk)
Breed (Rottweilers, Dobermanns, American Pit Bulls)

Question 7

When is parvovirus typically shed in faeces?

Answer 7

3-14 days post-infection

Question 8

When is the clinical disease of parvovirus typically present?

Answer 8

5-12 days post-infection

Question 9

What are the clinical signs of parvovirus?

Answer 9

Foul smelling, bloody diarrhoea
Vomiting
Leukopenia
Fever
May develop sepsis, then DIC

Question 10

A dog has acute vomiting and diarrhoea, what should you always screen for prior to admission?

Answer 10

Parvovirus

Question 11

How would you diagnose parvovirus?

Answer 11

Clinical signs/History (often young, incomplete vaccination)
Detection of faecal antigen with ELISA or PCR

Question 12

Compare the advantages/disadvantages of PCR and ELISA tests for parvovirus

Answer 12

ELISA:
A - in house, inexpensive, quick
D - specific but poorly sensitive (false negative possible)

PCR:
A - definitive diagnosis
D - lab test (wait time)

Question 13

What is the goal when treating parvovirus?

Answer 13

Restore fluid + electrolyte balance, avoid sepsis

Question 14

Outline a typical treatment plan for parvovirus

Answer 14

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)

Question 15

What organisms are responsible for Canine Infectious Respiratory Disease Complex (CIRDC)?

Answer 15

Viral:
Canine Parainfluenza Virus
Bacterial:
Bordetella bronchiseptica
Mycoplasma spp.

Question 16

CIRDC has HIGH ______ and LOW ______

Answer 16

CIRDC has HIGH morbidity and LOW mortality

Question 17

How is CIRDC transmitted?

Answer 17

Respiratory secretions

Question 18

Vaccines for CIRDC …..

Answer 18

Do not prevent infection, but should reduce severity of clinical signs

Question 19

What are the clinical signs of CIRDC?

Answer 19

Paroxysmal cough with terminal retch
Fever, anorexia, lethargy
SMLN enlarged
Erythematous oropharynx
“tracheal pinch” induced cough

Question 20

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?

Answer 20

Rest, isolate from other dogs, provide soft food

AB NOT JUSTIFIED

Question 21

A dog that has been in kennels recently returns to you after 7 days of persistent, non-productive coughing. How will you treat it?

Answer 21

AB: Doxycycline for 7-10 days
+/- Antitussives e.g. hydrocodone (NOT if cough is productive)
Continue rest + isolation from other dogs

Question 22

What must you do if you diagnose Ehrlichia canis?

Answer 22

Notify DPIRD

Question 23

What is Ehrlichia canis, and how is it transmitted?

Answer 23

Bacterial infection transmitted by Brown Dog Tick (Rhipicephalus sanguineus)

Question 24

What does Ehrlichia canis cause and what clinical signs occur?

Answer 24

Acute reduction in red blood cells (esp. platelets)
CS: fever, lethargy, thrombocytopenia, myalgia, anorexia, lymphadenopathy, petechia

Question 25

How do you definitively diagnose Ehrlichia canis?

Answer 25

PCR (DPIRD funded) or serological antibodies

Question 26

What in house tests help diagnose Ehrlichia canis?

Answer 26

Platelet count, PCV, buccal mucosal bleeding time (BMBT)

Question 27

How do you treat Ehrlichia canis?

Answer 27

Doxycycline for 28 days 5mg/kg PO q12hr OR 10mg/kg PO q24hr

Question 28

A client is worried about Ehrlichia canis, what advice will you give to them?

Answer 28

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)

Question 29

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?

Answer 29

Leptospirosis

Question 30

What questions may help if you suspect leptospirosis?

Answer 30

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?

Question 31

What are the clinical signs of Heartworm disease?

Answer 31

Coughing, exercise intolerance, weight loss, abdominal distension, lethargy

Question 32

What do heartworm antigen tests detect?

Answer 32

Proteins from adult female D. immitis (>6 months post-infection)

Question 33

What does a modified Knott test detect?

Answer 33

Circulating microfilariea of D. immitis (>6-7 months post-infection)

Question 34

If a dog has lapsed prophylaxis for heartworm, what must you do before recommencing prophylaxis?

Answer 34

Ensure no circulating microfilariea - perform modified Knott test

Question 35

What would your heartworm prophylaxis protocol be for a dog aged 2-7 months?

Answer 35

Start prophylaxis, but test for antigen and microfilariea 6 months later

Question 36

What would your heartworm prophylaxis protocol be for a dog older than 7 months?

Answer 36

Test for antigen and microfilariea prior to starting prophylaxis, if clear start prophylaxis and test again 6 months later

Question 37

Why should you never start heartworm prophylaxis without testing?

Answer 37

Sudden death of adult worms and microfilariea may result in thromboembolism leading to sudden death, or cause transient shock-like hypersensitivity

Question 38

A dog returns a positive heartworm antigen test, what is your next step?

Answer 38

Must confirm positive result - repeat antigen test (different brand) And perform Knott's test to determine microfilariea presence

Question 39

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?

Answer 39

Commence prophylaxis

Question 40

A dog is heartworm antigen negative but microfilariea positive. What is your next step?

Answer 40

Do not start prophylaxis - risk of shock. Must identify microfilariea (may be Dipetalonema)