Adenoviruses Flashcards
1
Q
What are some examples of adenoviruses?
A
- Mastadenovirus
- Aviadenovirus
- Siadenovirus
- Atadenovirus
- Ichtadenovirus
2
Q
What are the properties of adenoviruses?
A
- 5 serologically distinct genera
- Narrow host ranges; multiple serotypes
- Naked, icosadhedral virions
- dsDNA
- replication in nucleus with early and late transcription
- intranuclear inclusion bodies
- agglutinate RBCs
- some are oncogenic in rodents
- STABLE in environment (inactivate easily by disinfectants)
3
Q
Adenovirus replication: 3 phases
A
- Immediate early phase
- Early phase
- Late phase
4
Q
Immediate early phase replication
A
- Infect differentiated epithelial cells
- Fibers bind to coxsakievirus-adenovirus receptor (CAR)
- Virus engulfed by endocytosis of clathrin-coated pits
- Uncoated occurs in steps
- DNA is released into nucleus
- Expression of genes inhibiting IFN and control of cell cycle
5
Q
Early phase replication
A
- Early transcription: use host cell RNA polymerase
o early mRNAs are transcribed from scattered regions of both strands and then exported to cytoplasm
o translated into proteins controlling replication
6
Q
Late phase replication
A
- DNA replication: encodes it’s own DNA polymerase (early protein)
- Production of structural proteins
- Assembly in nucleus
o DNA enters particles after immature capsids are formed
o Capsids undergo a maturation process
o Then cells lyse and virions leak out
7
Q
What are the 2 diseases canine adenoviruses cause in dogs?
A
- infectious canine hepatitis (‘Rubarth’s disease”): CAV-1=systemic infection
- respiratory disease: CAV-2=respiratory infection
8
Q
What is pathogenesis of CAV-1?
A
- Viruses in urine, feces and saliva
- Initial infection and replication of tonsils and Peyer’s patches
- Viremia
- Lytic infection of ENDOTHELIAL and parenchymal cells in liver, kidneys, spleen, lungs
o Explains many of the lesions - *good candidate for vaccination as memory can have a chance
9
Q
What are the clinical features of CAV-1?
A
- Most asymptomatic or mild respiratory disease
- Systemic disease: 3 overlapping syndromes seen in puppies <6 months of age
- *dogs on streets: peeing and others drinking it
10
Q
What are the 3 overlapping syndromes seen in puppies <6months with CAV-1?
A
- Peracute: puppies found dead with massive liver necrosis
- Actue: fever, depression, loss of appetite, vomiting, bloody diarrhea, hemorrhages on gums (incubation: 4-8 days)
- Mild: may be result of ‘vaccine-modified’ disease (ex. partial immunity)
11
Q
How are CAV-1 infections diagnosed?
A
- Typical lesions
- INTRANUCLEAR INCLUSION BODIES (usually post mortem and by pathology)
- IHC/PCR
- Virus isolation
- Serology
12
Q
Viruria and CAV-1
A
- Major means of spread
- Recovered dogs can shed for 6 months
13
Q
Vaccines and CAV
A
- First using CAV-1: got ‘blue- eye’ (type III hypersensitivity)
- *now CAV-2=one serotype (different genotypes though)
- *antigenic relationship between CAV-1 and CAV-2 is close=cross protection
- **efficacy and routine use=why we rarely see ICH in practice
14
Q
CAV and other ‘dog viruses’ with wildlife
A
- Can infected wide variety of canids (Ex. coyotes)
- Foxes CAV-1=primarily causes CNS disease
15
Q
What are some other adenoviral diseases?
A
- Equine adenovirus disease (EAV-1,2
- Adenovirus hemorrhagic disease of deer
