Parvovirus

Question 1

what are canine and feline examples of parvovirus

Answer 1

canine parvovirus 2
feline panleukopenia virus

Question 2

what are parvovirus characteristics

Answer 2

• single stranded
• DNA
• non-enveloped
• capsid includes 2 proteins: VP1 and VP2

Question 3

VP2

Answer 3

more relevant capsid protein

binds to transferrin receptors in order to enter host cells

Question 4

what is the role of transferrin receptors in normal cells

Answer 4

transferrin binds iron –> complex cross-links transferrin receptors –> clathrin internalizes the receptor complex –> pulls iron into the cell

Question 5

what is the MOA of VP2 to infect host cells

Answer 5

parvovirus binds TfR instead of transferrin –> gets internalized into host cell

**requires specificity - cell must express TfR in order to be infected with Parvo

Question 6

VP1

Answer 6

lipolytic enzyme that aids in intracellular localization

Question 7

what kind of cells do parvoviruses target

Answer 7

rapidly dividing cells

adults: GIT
young: GIT, heart, brain

Question 8

where does parvovirus replication occur in the host cell

Answer 8

in the nucleus

Question 9

what host machinery does parvovirus require in order to replicate

Answer 9

requires DNA polymerase - only available in the S phase during actively diving cells

Question 10

can parvovirus induce cells to enter S phase

Answer 10

NO - can only infect cells that are already dividing

Question 11

environmental resistance of parvovirus

Answer 11

highly environmentally resistant
- does NOT have an envelope –> more stable in environment
- can withstand wide range of pH and temperature

Question 12

what disinfectants are effective and ineffective against parvovirus

Answer 12

effective:
- chlorine bleach
- trifectant
- accelerated H2O2

ineffective:
- quaternary ammonium compounds (target cell membranes which Parvo doesn’t have)

Question 13

clinical signs of parvovirus

Answer 13

adults: enteritis

young: enteritis + CNS and cardiac lesions
- cerebellar hypoplasia in kittens ONLY

Question 14

pathogenesis of parvovirus

Answer 14

1. oronasal exposure (ingestion or inhalation)
2. travels to lymphoid tissues (tonsils, LNs, thymus)
3. enters circulation to cause viremia
4. hematogenous spread to intestines

**does NOT go directly to intestines despite being ingested; must go to LNs first

Question 15

are puppies/kittens able to be infected in utero

Answer 15

yes

Question 16

intestinal lesions of parvovirus

Answer 16

intestinal crypt necrosis
- villus blunting

causes malabsorption and increased permeability
- fibrin + necrotic debris

Question 17

host evolution of parvovirus

Answer 17

feline parvovirus –> mutated VP2 to become infectious to dogs –> canine parvovirus 2 –> mutated VP2 to become infectious to raccoons –> infectious to cats

Question 18

canine parvovirus 1

Answer 18

minimal disease; minute virus of canines

Question 19

canine parvovirus 2

Answer 19

generalized disease in puppies (enteritis, myocarditis, lymphopenia)

strains: 2a, 2b, 2c

Question 20

why must puppies be vaccinated for parvovirus from an early age

Answer 20

protected by passive immunity from maternal antibodies but will still have a window of susceptibility
- if dam has low titers - puppies could be susceptible as early as 4-6 weeks

need to vaccinate early and serially until maternal antibodies are gone in order for vaccine to be effective

Question 21

feline pankleukopenia virus

Answer 21

generalized disease in kittens
- panleukopenia
- enteritis (anorexia, vomiting, diarrhea)
- cerebellar hypoplasia

older cats can have subclinical infections

Question 22

what happens if kittens are infected in utero during early, mid, late, and post gestation

Answer 22

early: fetal death
mid-late: abortions and mummies
late: developmental defects
- cerebellar hypoplasia, hydranencephaly, optic nerve atrophy, retinopathy
postnatal: intestinal lesions, leukopenia

Question 23

CPV-2 diagnostics

Answer 23

1. fecal ELISA - detects antigen
2. serology - hemagglutination assay + antibody ELISA
   - unable to differentiate vaccine vs infection antibodies

Question 24

FPV diagnostics

Answer 24

clinical signs + CBC (leukopenia)

can also do:
- serum neutralization
- hemagglutination inhibition
- fecal ELISA for CPV-2