Infectious Diseases - Dogs Part 3

Question 1

Canine distemper virus

Answer 1

RNA virus very susceptible in the environment

Parmyxoviridae family

Question 2

Pathogenesis of canine distemper virus (this is a very long answer)

Answer 2

spread through water droplets –> upper resp tract epithelium –> multiplies in tissue macrophages –> spreads to local lymphatics in tonsils and bronchial lymph nodes
by 2-4d PI, viral number increases in tonsils and retropharyngeal bronchial LNs
by 4-6d PI, virus multiplication in lymphoid follicles of spleen + gut associated lymphatic tissue of lamina propria of stomach and small intestine, mesenteric lnn, and kupffer cells in the liver
rise of proliferation –> pyrexia and lymphopenia (both T and B cells)
further spread
further spread to epithelial tissue and CNS on days 8-9PI
Day 14 PI, animals with adequate CDV antibody tigers and cell mediated cytotoxicity clear virus from most tissues

Question 3

Poor immunity to canine distemper virus leads to spread in the

Answer 3

skin, exocrine, endocrine, glands and epithelium of GI tract, resp tract, genitourinary tract and brain

Question 4

Clinical signs of distemper virus infection

Answer 4

listlessness, decreased appetite, fever, upper resp infection
bilateral serous oculonasal discharge, biphasic pyrexia, keratoconjunctiva sicca
GI signs, diarrhea
skin lesions - vesicles and pustules, nasal and digital hyperkeratosis (hard pad disease)
Resp - tachypnea, coughing, pneumonia
Neuro signs - meningeal inflammation, seizures, cerebellar and vestibular signs, sensory ataxia, myoclonus

Question 5

Diagnosis of canine distemper virus

Answer 5

3-6m old unvaccinated puppy
peripheral blood smear - intracytoplasmic distemper inclusion bodies within erythrocytes
interstitial lung pattern with thoracic rads
MRI
CSF tap - anti CDV antibody, increased protein count
serology
PCR - Buffy coat cells, whole blood, serum and CSF
Serum antibody testing - neutralizing antibodies = god standard to check immunity (IgG levels), indirect FA testing titres

Question 6

Treatment of canine distemper virus

Answer 6

supportive - antibiotics and steroids (dexamethasone) to reduce CNS edema
seizure medication
poor prognosis

Question 7

Prevention of canine distemper virus

Answer 7

modified live vaccines most commonly used
vector vaccine - canarypox based vaccine to protect naive pups
non-living antigen vaccines do not produce sufficient immunity
Vaccine failure - maternal antibodies, adverse reaction, failure to control vaccine temperature

Question 8

Duration of immunity to canine distemper virus after vaccination

Answer 8

after initial series (6, 9, 12, 16w) and 1 year booster, every 3 years

Question 9

Public health risk of canine distemper virus

Answer 9

Pagets disease

Question 10

Canine adenovirus type 1

Answer 10

Canine infectious hepatitis virus

highly resistant to environmental inactivation

Question 11

Pathogenesis of canine adenovirus type 1

Answer 11

oronasal exposure –> multiplication in tonsils –> regional lymph nodes –> lymphatics –> blood
severe viremia 4-8d PI, spreads through all tissues
hepatic parenchyma cells, vascular endothelium and CNS are prime targets of viral localization and injury
antibodies form by day 7 PI
acute hepatic necrosis

Question 12

Clinical signs of canine adenovirus type 1

Answer 12

dogs <1 year usualy
dogs become moribund and die within a few hours
pyrexia, tachycardia, tachypnea, coughing
tonsilar enlargement, lymphadenopathy, hemorrhagic diathesis, widespread bleeding
icterus is uncommon
see corneal edema and anterior uveitis in persistent stage

Question 13

Diagnosis of canine infectious hepatitis

Answer 13

CBC - leukopenia, lymphopenia, neutropenia, thrombocytopenia
Biochem - hyperglobulinemia, increased ALT, AST, ALP
coagulation abnormalities
urinalysis - proteinuria
Abdominocentesis - yellow to hemorrhagic fluid
serology - very high tiers after infection (compared to vaccination)
Pathology - swollen liver and mottles, multiple ecchymotic hemorrhages

Question 14

Treatment of canine infectious hepatitis

Answer 14

supportive therapy

use a MLV for CAF2 vaccine for prevention

Question 15

Which of the following is FALSE regarding canine parvovirus?
A) younger dogs are predisposed
B) incubation period is 1-5 days
C) highly contagious, often fatal, very stable and resistant in environment
D) CPV-1 is more common than CPV-2

Answer 15

D - canine parvovirus 2 is most common

Question 16

Breed predisposed to canine parvovirus

Answer 16

rottweilers

also Dobes, labs, German shepherds, alaskan sled dogs

Question 17

Clinical signs of canine parvovirus

Answer 17

GI signs - vomiting, yellow/hemorrhagic diarrhea, anorexia, severe dehydration
death within 2 days
bone marrow - severe leukopenia (lymphopenia)
myocarditis - rare
thrombosis, bacteruria, IV catheter infection

Question 18

Diagnosis of canine parvovirus

Answer 18

clinical signs
leukopenia (not all dogs)
Fecal ELISA antigen test, fecal PCR
EM of feces
serology to check immune status
pathological findings - hemorrhagic enteritis, necrosis of crypt epithelium in SI, immunofluorescence to stain for CPV

Question 19

T/F it is ideal to do a fecal ELISA antibody test to diagnose canine parvovirus

Answer 19

False, the onset of disease is so fast that immune response cant occur - you’re better off testing for the antigen

Question 20

Treatment of canine parvovirus

Answer 20

restore fluids and electrolytes
antiemetic agents
food consistently (nasoesophageal tube)
gastric rotectants
whole blood, plasma, colloids

Question 21

Prevention of canine parvovirus

Answer 21

immunity after infections but vaccinate anyways
modified live vaccine, duration of immunity 3-7 years
maternal antibodies can prevent an immune response - last vaccination 16w of age

Question 22

Canine coronavirus

Answer 22

highly contagious, seen with or without diarrhea, neonates most susceptible
incubation is 1-4d

Question 23

Compare the clinical signs of enteric coronavirus to pan tropic coronavirus

Answer 23

Enteric - subclinical to mild diarrhea, feces is orange and , malodorous, loss of appetite and lethargy
Pantropic - lethargy, anorexia, vomiting, hemorrhagic diarrhea, leukopenia, neuro signs, resp difficulty

Question 24

Diagnosis of coronavirus

Answer 24

EM of fresh feces
fecal PCR
serum VN and ELISA for CCOV antibodies (only confirms exposure)

Question 25

Treatment of coronavirus

Answer 25

supportive care
death is uncommon
MLV - vaccinate mom

Question 26

Canine Rotavirus

Answer 26

affects pups younger than 12w
mild diarrhea
Dx - fecal ELISA for rotavirus antigen, fecal EM
Tx - supportive care

Question 27

Which is FALSE regarding canine herpesvirus?
A) is stable in the environment
B) Pups can be infected in utero, through birth canal, from contact with litter mates, from oronasal secretions from dam
C) is cytocidal
D) can cause acute death in neonates

Answer 27

A - is not very stable in the environment

Question 28

what does cytocidal mean

Answer 28

causes tissue necrosis and localized mucosal or generalized infections in young or immunocompromised animals

Question 29

Pathogenesis of canine herpesvirus

Answer 29

if animal <1w - fatal generalized infection
if animal >2w - mild or inapparent infection
viral replication in older animal - nasopharynx, genital tract, tonsils, retropharyngeal lymph nodes, bronchial lymph nodes, conjunctival tissue, lungs
in utero infection - abortion or still births
systemic infection -multifocal hemorrhagic necrosis, DIC, thrombocytopenia

Question 30

Clinical signs of neonates with herpesvirus

Answer 30

acute death’
dull, weight loss, depressed, lose interest in feeding, pass soft stools
petechial hemorrhages on MM

Question 31

Clinical signs of adults with canine herpesvirus

Answer 31

mild or inapparent upper resp infeciton
genital infections - petechiae, ecchymotic submucosal hemorrhage
vesicle lesions

Question 32

Most reliable test for canine herpesvirus is

Answer 32

PCR

Question 33

T/F: there is no vaccination for canine herpesvirus

Answer 33

false