Family: Parvoviridae Flashcards
What is the smallest known DNA virus?
Parvovirus
What is the structure of Parvovirus?
small, non-enveloped, icosahedral capsid virus containing a linear ssDNA genome
What are the 4 genera of Parvoviridae?
- Parvovirus
- Dependovirus
- Amdovirus
- Bocavirus
Where does Parvovirus replicate?
within the host’s nucleus, forming intranuclear inclusion bodies
What kind of sequence is found at the terminal ends of Parvovirus? What 2 functions is this for?
palindromic sequences
- enables ends to make a hairpin
- facilitates packaging of virions
What happens at the 5’ and 3’ ends of the Parvovirus genome?
5’ = capped
3’ = polyadenylated
What 2 proteins does Parvovirus make in large amounts? What are the 4 actions of NSP1?
VP-1 and VP-2
- binds DNA
- serves as a helicase
- serves as an endonuclease
- interferes with cellular DNA replication
What are the 6 steps to Parvovirus replication?
- attachment and entry
- translocation of viral DNA into nucleus
- transcription and translation of viral nonstructureal protein and nucelocapsid
- DNA replication
- virus assembly within nucleus
- release from the cell through lysis
What are 6 common genera of Parvovirus that cause disease?
- PROTOPARVOVIRUS - feline panleukopenia, mink enteritis, canine parvovirus-2, porcine parvovirus, rodent parvovirus, rabbit Lapine parvovirus
- AMDOPARVOVIRUS - Aleutian mink disease
- AVEPARVOVIRUS - chicken and turkey parvovirus
- BOCAPARVOVIRUS - bovine parvovirus, canine minute virus (canine parvovirus-1), canine bocavirus-1
- DEPENDOVIRUS - goose and duck parvovirus
- ERYTHROPARVOVIRUS: nonhuman primate parvovirus
What is feline panleukopenia (Feline Distemper)?
highly contagious viral disease of cats characterized by sudden onset, fever, inappetence, dehydration, depression, vomitting, decreased numbers of circulating blood cells, and a high mortality rate
What happens when Feline Panleukopenia virus causes infection within the uterus? What animals are susceptible?
abortions, stillbirths, early neonatal death, cerebellular hypoplasia
all members of the cat family (Felidae)
How is Feline Panleukopenia virus transmitted? What happens in the early stages of infection?
direct contact with infected cats or their excretions
virus is shed in feces, urine, saliva, and vomit
What are 2 intestinal lesions common in Feline Panleukopenia? 2 brain lesions?
- flaccid small intestins with hemorrhage and mucosal sloughing
- blunt and fused villi
- cerebellar atrophy
- hydeocephalus
What is seen on hematology in Feline Panleukopenia? How can it be diagnosed? What is not recommended?
sharp decrease in WBC in CBC
fecal ELISA
serology - non discrimination between infected and vaccinated animals (not DIVA)
What is characteristic of Canine Parvovirus infection? What makes this virus difficult to fight? What are the 3 different strains?
bloody diarrhea
can survive for long periods (> 1 year) in the environment
CPV-2a: after 1980
CPV-2b: 1986
CPV-2c: new strain
What is the host range of Canine Parvovirus? What is the mode of transmission?
dogs, especially those less than 12 weeks and unvaccinated adults
fecal-oral, can persist on fomites
- virus is shed for a few days before the onset of clinical signs
Lifecycle of Canine Parvovirus:
Where does Canine Parvovirus begin replication? What are the 2 possible routes from there?
lymphoid tissues of oropharynx, mesenteric lymph nodes, bone marrow, and thymus
- GI TRACT —> epithelium of the tongue, oral cavity, esophagus, and intestinal tract (esp. germinal cells in crypts) are infected, causing malabsorption and incrased intestinal permeability resulting in fever, vomiting, diarrhea, dehydration and abdominal pain
- BONE MARROW —> lymphopenia and neutropenia due to the sequestration of neutrophils in damaged GI tissue (disordered coagulation)
What can happen to dams infected by CPV-2 variants early in gestation? How are the puppies infected in utero or up to 2 weeks old affected?
infertility, resorption, abortion
may develop viral myocarditis
What are the 2 forms of Canine Parvovirus?
- INTESTINAL: vomiting and (bloody) diarrhea
- CARDIAC: very young puppy’s heart muscle is affected, resulting in sudden death
What does CPV’s tropism for intestinal epithelium lead to? What is a common secondary problem?
collapse of intestinal villi, epithelial necrosis, and hemorrhagic diarrhea (gastroenteritis)
bacteremia by normal gut flora caused by the depletion of lymphocytes and compromised GI system
What 2 things does the severity of clinical signs of Canine Parvovirus infection depend on?
- virus strain
- host immunity —> stress (weaning, overcrowding), materinal antibodies, concurrent infection
What are the 2 mechanisms of death in Canine Parvovirus?
- diarrhea, vomiting, dehydration = SHOCK
- loss of intestinal barrier, bacterial invasion = SEPTIC SHOCK
What are common necropsy findings in a dog infected by CPV?
- discoloration of intestinal wall
- fibrin on serous surface
- villi collapse
- crypt lamina dilated and filled with necrotic debris
How is Canine Parvovirus diagnosed? What is not recommended?
- sudden onset of foul-smelliing, blood diarrhea in a young dog
- CBC: leukopenia, neutropenia, lymphopenia
- abnormal coagulation test
- cardiac troponin I plasma marker
- hypoproteinemia, hypoalbuminemia, hypoglycemia
- fecal ELISA
- PCR
serology = most dogs are vaccinated against it or have been previously exposed —> no DIVA
What 2 kinds of vaccines are available for Canine Parvovirus? How is the age of vaccination determined?
- attenuated live: NEVER administered to pregnant bitches because it can cause disease in the developing fetus
- monovalent: intranasal
determination of MDA titers by serological testing
- low protective titer = 6 weeks
- high protective titer = wait longer
How are puppies of unknown immune status vaccinated for Canine Parvovirus?
high-titer attenuated live CPV vaccine at 6, 9, and 12 weeks
What tropism does Porcine Parvovirus have?
lymphotropic —> lives/persists in B and T cells for a long time
What happens when Porcine Parvovirus infection occurs in the first month of pregnancy? From day 30-70? After 70 days?
- fetus dies and is absorbed
- fetus dies and is mummified
- growing pig may be able to fight off infection
(SMEDI = stillbirth, mummification, embryonic death, infertility)
What are 9 common differential diagnoses for Porcine Parvovirus infection?
- Aujesky’s disease
- leptospirosis
- foot-and-mouth disease
- classical swine fever
- Japanese encephalitis
- porcine brucellosis
- porcine reproductive and respiratory syndrome
- porcine enterovirus infection
- vesicular stomatitis
What animals are affected by Aleutian mink disease? What does it cause?
mink, ferrets
dysregulated immune system - postinfectious antibody response —> perivascular and glomerular immune complex formation causes membranoproliferative glomerulonephritis and narrowing of the lumen of the vessel
What serum pattern is observed in Aleutian mink disease?
polyclonal gammopathy —> gamma globulin levels reach 62.4% (usually 14.3%)
What does Equine Parvovirus cause? What do recently infected horses show?
equine parvovirus hepatitis (Theiler’s Disease)
non-clinical hepatitis with elevated serum liver enzymes
What are the 2 modes of transmission of Equine Parvovirus?
- BIOLOGICAL: administration of biological products containing EqPV-H (tetanus antitoxin, botulinum antitoxin, S. equi antiserum, pregnant mare serum, allogenic stem cell preparations, plasma products) with cases occuring 4-13 weeks after administration
- NON-BIOLOGICAL: sporadic, without history of receiving biological products
What are the 2 clinical forms of Equine Parvovirus?
- asymptomatic infection: most common
- clinical hepatitis: mild illness to acute fulminate liver failure
