Circoviridae Flashcards
Circovirus
Smallest known viral particles!
- porcine circovirus (PCV-1)
- porcine circovirus (PCV-2): postweaning multisystemic wasting syndrome
- beak and feather disease virus: psittacines
- TT virus: human posttransfusion hepatits, uncertain pathogen
Gyrovirus
Chicken anemia virus
- thymic depletion by apoptosis, immmunosuppression, anemia, hemorrhage
Circoviridae genome
Closed, circular ssDNA
- nonenveloped
Why is chicken anemia virus not in the family circovirus?
Has negative sense DNA
- classified as a gyrovirus
- also has protruding pentagonal tumpet-shaped capsid units
Infection of circociruses resutl in
Viral-induced damage to lymphoid tissue and immunosuppression
CAV
Affects young chickens
- anemia, lymphoid depletion, hemorrhaging
- increased mortality
ORF2
Open reading frame of PCV-2 that encapsidates an ambisense genome
- 66% similarity in ORF2 between PCV1 and 2
PMWS
Postweaning multisystemic wasting syndrome
- affects nursery and fattening pigs
- growth retardation, paleness of skin, dyspnea, increased mortality rates
What diseases are associated with PCV2?
- PMWS
- porcine dermatitis
- nephropathy syndrome
- reproductive disorders
- porcine respiratory disease
What 3 conditions are required to definitely diagnose PMWS?
- clinical signs including progressive wasting after weaning
- characteristic microscopic lesions
- detection of PCV2 within the lesions
Canine circovirus
Shares similarity to porcine circovirus
- not all infected dogs become ill
- no vaccine available
Canine circovirus transmission
Direct contact with infected dog, or infected vomit/diarrhea
Canine circovirus can exist as a coinfection with ______
Canine enteric coronavirus, cryptosporidium, clostritidum, giardia, salmonella, or campylobacter
Canine circovirus symptoms
- vomiting
- diarrhea (possibly hemorrhagic)
- hematochezia
- ascites
- pleural effusion
- DIC
Examination of infected tissues revealed:
Fibronecrotizing vasculitis
