Family: Parvoviridae, Feline Parvovirus Flashcards
Properties of Parvoviridae family
Noneveloped icosahedral virion
Virion capsid is composed of 60 protein subuntis, T=1
Single-stranded DNA genome which are linear
Replication occurs in the nucleus of dividing cells
Genus Parvovirus replication properties
Virus replication occurs only in cells that pass through mitotic S phase (actively dividing cells)
Cannot replicate in stationary cells, as they rely on enzymes of actively dividing cells (mitosis)
Feline Parvovirus
- common name
- epidemiology
Feline Panleukopenia (FPV)
Virus is ubiquitous because of its contagious nature and capacity for persistence in the environment
FPV is maintained in a population by environmental persistence rather than prolonged viral shedding
Transmission of FPV
Cats are infected oro-nasally by exposure to infected animals, their feces, secretions, or contaminated fomites
In-utero transmission
Mechanical transmission by flies
2 common pathogenesis of FPV
Panleukopenia
Enteritis
Pathogenesis of Panleukopenia of FPV
Hallmark of the diseae
The more severe the leukopenia, the poorer the prognosis
Leukopenia - destruction of white blood cells, including lymphocytes, neutrophils, monocytes, and platelets
Thrombocytopenia may accompany leukopenia
Pathogenesis of Enteritis of FPV
Virus selectively damages replicating cells in the crypts of intestinal mucosa
Loss of cells from tip of villus continues as a normal however, the virus replicates and destroys cells of crypts so there is no replacement of the lost absorptive cells at the tips of villi with cells from the crypts
The result is shortening of intestinal villi, marked villus blunting, malabsorption, and diarrhea
3 infection types of FPV
In-utero infection
Central nervous system infection
Disseminated intravascular coagulation
In-utero infection with FPV
Early in-utero infection: early fetal death and resorption with infertility, abortions, birth of mummified fetuses
Infection closer to end of gestation: birth of live kittens with varying degree of damage
CNS infection with FPV
CNS, optic nerve, and retina are susceptible to damage by FPV
Cerebellar hypoplasia is observed in fetuses infected during the last 2 weeks of pregnancy and first 2 weeks of life
Kittens with marked ataxia and hydraencephaly
DIC infection with FPV
Kittens with FPV are susceptible to secondary bacterial infection
Gram negative is common sequelae of systemic FPV infection
LPS (endotoxin) induces expression of tissue factor on endothelial cells which activates coagulation, resulting in DIC
Diagnosis of FPV
Hematology - leukopenia, neutropenia
Serology: simple sample antibody titers do not distinguish between active infection or post exposure to virulent strains
Paired serum samples - 1st during illeness and 2nd 2 weeks after
Vaccination of FPV
Modified Live Vaccine should not be administered to:
pregnant cats, immunosuppressed cats, sick cats, kittens less than 4 weeks old
Time of vaccination:
Kittens receive 2 or 3 MLV doses SC, 3-4 weeks apart; 1st vaccine given at 6-9 weeks of age and last dose should not be given before the kitten is 16 weeks old
