Adenoviridae Flashcards
Adenoviridae morphology
non enveloped
hexagonal
icosahedral symmetry
capsid shell with 720 hexon subunits arranged as 240 trimers
12 vertex penton capsomers each with a fiber protrude from surface of capsid
Adenoviridae genome
non segmented
linear
double stranded DNA
Adenoviridae replication
takes place in the nucleus
released by cell lysis
intranuclear inclusion bodies are formed with virions inside
Adenoviridae general properties
agglutinate RBCS oncogenic stable in environment inactivated by many common disinfectants most have narrow host ranges
Adenoviridae pathogenesis
acute respiratory or gastroenteric disease (mostly subclinical)
Penton and fiber proteins are
part of the capsid and toxic to cells
Immunosuppression with Adenoviruses
inhibition of class I MHC antigen transport by E3/19K
TNF induced apoptosis is blocked by E3/14.7K
blocks interferon induced protein kinase R-mediated inhibition
modulates antiviral inflammation by inhibition nuclear factor kappaB
Adenovirus pathogenesis
latent in lymphoid tissue
reactivated with immunocompromisation
highly pathogenic in these animals
can also be oncogenic : E1A inactivates the Rb protein, E1B inactivated p53 protein
Genera of Adenoviridae
Mastadenovirus (mammalian with single penton fiber)
Aviadenovirus (birds- each penton fiber is bifurcated)
Infectious Canine Hepatitis
ICH
Rubarth’s disease
Canine adenovirus 1 (CAV 1)
CAV 1 / ICH
infects canids and bears
found in all secretions and excretions
shed in urine for 6-9 months
oronasal transmission
CAV 1 replication
macrophages kupffer cells hepatocytes vascular endothelium parenchymal cells
CAV1 target organs
liver
spleen
kidneys
lungs
CAV 1 cytotoxic effects
cellular injury to liver, kidney, and eye
Dogs with sufficient antibody titers show _____ clinical evidence of disease with CAV1
little
In acute cases of CAV 1
antibody response by day 7 should clear the virus from the blood and liver
low antibody titer with CAV 1
leads to widespread centrilobular to panlobular hepatic necrosis
partial immunity during a CAV 1 infection may lead to
chronic active hepatitis and hepatic fibrosis
Corneal edema in CAV 1
20% of infections
less than 1% of dogs after vaccine
seen in recovery or chronic cases
Pathogenesis of ocular lesions in CAV 1
- enters the eye via the uveal tract
- localizes in the endothelium of the choroid and causes mild uveitis
- 4-6 days post infection the virus enters the aqueous humor and replicates
- formation of viral antibody immune complex
- complement activation and neutrophil chemotaxis
- damage to endothelium and accumulation of edematous fluid
- days 8-21 macrophages remove immune complexes and the cornea clears
CAV 1 secondary bacterial pyelonephritis
most common in dogs under 1 yr
unvaccinated dogs are susceptible
mostly asymptomatic but can range from slight fever to death
CAV 1/ ICH per acute cases
become moribund and die within a few hours of onset of clinical signs
CAV 1/ ICH acute cases
fever, vomiting, abdominal pain, hyperemia, jaundice, subcutaneous edema
corneal edema during recovery
encephalitis in foxes
CAV 1/ ICH necropsy
paint brush hemorrhage
necrosis in liver
white foci in kidney cortex
