Lecture 6: Canine Viruses 1 Flashcards
What is the family and subfamily of canine herpes virus
- Family: Herpesviridae
- Subfamily: Alphaherpesvirinae
List 5 common canine respiratory viruses
- Canine Influenza
- Canine Herpes virus 1
- Canine adenovirus 2
- Canine distemper virus
- Canine para influenza
Describe the pathogenesis of canine herpes virus in adults, neonates, and fetuses
- Pathogenesis:
o Adult: infect via resp/repro tract = localized infection
Quick acute infection (viremia) -> latency
o Neonate: infect via ingest/inhale in birth canal/contact/fomites
>2 week: viremia and acute local infection
< 1 week: epithelial cell replication, leukocyte associated viremia = necrotizing vasculitis or like adult infection
o Fetus: infect in utero
leukocyte associated viremia = necrotizing vasculitis
What are the clinical signs of canine herpes virus in adults and pregnant animals
o Adults; subclinical (latent), mild rhinitis, vesicular vaginitis, posthistis
o Pregnant animals: early and late term abortion, still birth
What are the clinical signs of canine herpes virus in neonatal animals - describe the histological lesions you would expect
o Neonate: eosinophilic intranuclear inclusions surrounded by clear halo and marginated chromatin = in liver/adrenal glands/lungs/spleen/kidney/lymph node
Kidney: petechiae of renal cortex, tubular necrosis,
Liver: multifocal necrosis and
Lungs: small coalescing pale foci of necrotizing interstitial pneumonia – fibrin
Eye; corneal edema/cataracts
Bran: viral nucleic acids in cerebellum and cerebrum
How to diagnose canine herpes virus (3 ways)
- Dx: virus isolated from fresh lung/liver/kidney/spleen
o Histology for intra-nuclear inclusion bodies
o Virus neutralization assay (OVC lab)
How to control/prevent canine herpes virus
- Control: no vaccine – colostrum provides passive immunity
o C-section prevent contamination at birth (may already be infection from placenta)
What family is the agent for Canine infectious hepatitis
- Family: Adenoviridae
What are the viral characteristics of agent for Canine infectious hepatitis
- Virus: non-enveloped, with pentons that have projecting fibres (allow attachment to receptors
o Virus stable in environment
You may see intranuclear eosinophilic inclusions in a
section of liver infected with
A Herpesvirus
B Adenovirus
C Pox virus
D Pestivirus
E Coronavirus
A
You may see intranuclear basophilic inclusions in a
section of liver infected with
A Herpesvirus
B Adenovirus
C Pox virus
D Pestivirus
E Coronavirus
B
Two of the organs impacted by canine adenovirus- 1 infection is
the brain and kidney. What are the mechanisms of pathogenesis
of brain and kidney lesions? (3 marks).
Brain:
- endothelial cell damage cytopathic effect due to direct viral replication
- type 3 HS due to circulating immune complexes that can deposit in blood vessels and induce vasculitis
Kidney:
- tubular epithelial cells and endothelial cells
- type 3 HS due to circulating immune complexes that can deposit in kidney tubule epithelium and impact filtration ability or deposit in blood vessels of kidney and induce vasculitis
What a type 3 HS? What are the 2 types?
- Type 3 HS: antibody/antigen complex
o Circulating – deposit in vessel walls (=vasculitis) or in kidney (= damage filtration)
o Local/Arthus rxn – attract complement = attract neutrophils = tissue damage
What does CAV1 cause
- Canine Adenovirus 1 = infectious canine hepatitis
What are the target species of CAV1
o Target: dog/coyote/fox/canid/bears – subclinical dz widespread
What age is susceptible to CAV1
o Time: infection clinically significant <1yr (but unvx = can get any age)
How is CAV 1 transmitted
o Transmit: fomites/oronasal maybe ecto-parasite (not aerosol)
Virus excreted acutely (5-10day) in saliva/feces/resp mucus and chronically in urine (6-9 moths after)
What is the pathogenesis of CAV1
o Pathogenesis: viral ingestion > tonsil cervical LN/thoracic duct/blood in 5 days
Viral replication in cells = cytopathic effect: hepatocyte (acute hepatitis)/renal tubule (nephritis)/vascular endothelium (hemorrhage/DIC)
Antibody production = complex formation = circulating (renal damage) and local (corneal edema/opacity type 3 HS
Both types of pathogenesis can affect brain
What are the clinical signs, bloodwork, and histopath lesions of CAV1
o Clinically: lethargy/pale MM/tender abdomen/icteric/vomiting
BW: pyrexia/leukopenia/lymphocytosis/neutrophilia/high ALP/coagulopathy/proteinuria/neutralizing Ig
blue eyes (anterior uveitis/corneal edema/opacity – will resolve spontaneously)
Multifocal lung hemorrhage
Thickened/enlarged gallbladder
Hemorrhagic lymph nodes
Segmental hemorrhagic enteritis
Oral mucosal hemorrhage
Cerebral hemorrhage
Large/friable/yellow/petechiae liver – basophilic intranuclear inclusionis surrounded by clear zone
How to diagnose CAV1
o Dx: hematological results, serology, virus isolation/IF or histopath (if postmortem)
How to control/prevent CAV1
o Control: passive immunity (colostrum) – 5-7 weeks (14-16 week gone)
Vaccine: killed vaccine – require frequent doses
* Modified live: 3-5 year protection – can localize in kidney = shed in urine or cause blue eye – IM/SC
* Contain either CAV1 or 2 not both
What does CAV2 cause
- Canine adenovirus 2 = infectious canine tracheobronchitis (kennel cough)
What are the causes of CAV2
o Viral cause: Canine parainfluenza virus/adenovirus 2/distemper virus
o Bacterial cause: Bordatella bronchiseptica or B. brronchiseptica commonest
Pseudomonas
E. coli
Klebseilla pneumoniae
Streptococcus
What are the risk factors of CAV2
o Risk factors: high density housing, mixing dogs, stress, contact with wildlife/rodent/cat (B. brronchiseptica hosts), airway dz
What are the features (family/type) of the viruses causing CAV2
o Virus: Adenoviridae (dsDNA) or Paramyxoviridae (-ssRNA)
how is CAV2 transmitted
o Transmit: ocular/resp secretions – aerosols/direct/fomite = very contagious
Shed 8-10 day post infection (bordatella shed = 3 months)
What are the clinical signs of CAV2
o Clincically:
Uncomplicated: harsh dry cough/watery nasal discharge/pharyngitis/tonsiltis
* Virus rerplicate in resp epithelium
* Self limiting – reduce stress/exercise (mild 1-2 wk, severe 3-4 wk)
Complicated: lethargy/fever/anorexia/dry hacking honking cough/gagging
* Young unvx puppies/immunocompromised/old
* Viirrus and bacteria replicate in resp epithelium = can’t generate Ig response = viremia/2 bacterial infection
How to control CAV2
o Control: modified live vx: DAPPV (distemper/adenovirus/parainfluenza/parvo) – also prevent against CAV1
Modified live parainflenza avirulent intranasal bordatella vx
What is the family and subtypes of canine influenza
- Canine influenza
o Family: Orthomyxoviridae
o Subtype: H3N8 and H3N2
How did canine influenza develop
o Antigenic shift: related to equine influenza (mutated into the canine population)
What is the target cells of canine influenza virus
o Pathology:
Target cell: macrophages + resp epithelium
Influenza viral antigen in alveolar macrophage
Can H1N1 or H5N1 transmit to dogs
o H1N1 can transmit to dogs but not effectively
o H5N1 (HPAI) can. Transmit to dogs (consume infected animals)
What are the clinical signs of canine influenza
o Clinically: unreliable clinical signs – cough/sneeze/nasal discharge
How to control canine influenza
o Control: monovalent/bivalent vx for H3N8/H3N2 – will reduce severity/duration not prevent infection
How to diagnose canine influenza
o Dx: viral isolation/immunoassay/RT-PCR/serology for viral Ig
