Family: Adenoviridae Flashcards
Where were Adenoviridae first recovered from?
human adenoid tissue
What are the 5 genera of Adenoviridae?
- Mastadenovirus
- Aviadenovirus
- Atadenovirus
- Ichtadenovirus
- Siadenovirus
What is the structure of Adenovirus like?
non-enveloped, hexagonal capsid with icosahedral symmetry with fibers protruding from each penton base
How do Mastadenovirus and Aviadenovirus compare in structure?
M = one fiber gene
A = two fiber genes
What is the genome of Adenoviridae like? Where does it replicate?
single linear dsDNA with inverted terminal repeats
in the nucleus
What are the functions of the 7 polypeptides on the capsid of Adenoviridae?
II - hexon protein
III - penton base
IIIa - link adjacent faces
IV - fiber
VI, VIII, IX - stabilize hexon capsomere lattice
What are the functions of the 4 polypeptides found on the core of Adenoviridae?
V - bridge between penton and core
VII - major core protein
TP - attach viral genome to nuclear matric, circularize viral DNA, DNA replication primer
Mu - unknown
Adenoviridae classification:
What determines the target cell specificity and attachment of Adenoviruses? How is their replication different?
fiber proteins
- early and late phases —> error-prone
- release viral capsid in cytosol then transferred into nucleus
What are the 6 steps of Adenovirus replication?
- virus attached to host receptors through the fiber glycoproteins and is endocytosed into vesicles
- disruption of endosome releases viral capsid in the cytosol and is released into the nucleus
- transcription of early genes (E genes) and replication of DNA in nucleus
- transcription of late genes (L genes), mostly encoding for structural proteins
- assembly of new virions in nucleus
- virions release by lysis
What are the 3 types of Adenovirus infection? Where is it common to see each?
- LYTIC: results in cell death —> mucoepithelial cells
- LATENT/OCCULT: virus remains in host —> lymphoid tissue
- ONCOGENIC TRANSFORMATION: uncontrolled cell growth and replication —> group A viruses in hamsters
What causes infectious canine hepatitis? How was it distinguished from canine distemper?
(Rubarth’s Disease)
Canine Adenovirus-1 and 2
inoculation into ferret —> resistant (only infects domestic and wild dogs)
What are 7 clinical signs of infectious canine hepatitis?
- pyrexia
- nausea
- vomiting
- loss of appetite
- jaundice
- light-colored stool
- stomach enlargement
What are 4 common postmortem findings in canine infectious hepatitis?
- vascular endothelial damage leads to petechial hemorrhage on mucous membranes and skin
- swollen, mottled liver with rounded, lobular edges*
- gall bladder edema*
- intranuclear inclusion bodies in hepatocytes
What is the pathogenesis of Canine Adenovirus-1, causing infectious hepatitis?
- oro-nasal infection
- replication in tonsils, Peyer’s patches, and other lymphatic tissues
- viremia allows for replication in vascular cells in many organs —> hepatocytes, endothelial cells of renal glomeruli, cornea, uvea
How does blue eye result from canine infectious hepatitis? What are the 7 steps?
immune complex deposition in the cornea and uvea, cauing persistent inflammation
- CAV-1 enters eye via uveal tract and localizes in vascular endothelial cells, causing uveitis
- CAV-1 specific antibody response increases in the bloow to reach the eyes via uveal duct
- CAV-1 is free in the aqueous soluition and endothelial cells and forms a viral-antibody immune complex
- complement fixation on IC and intranuclear inclusion body formation
- corneal endothelial cell loss allows aqueous solution to enter the cornea (corneal edema = blue eye)
- unveal inflammation may lead to blockage of filtration angle and glaucoma
What vaccine is best against canine infectious hepatitis?
homologous > heterologous
What is egg drop syndrome? What causes it? What is the natural host?
infectious disease of laying hens resulting in thin-shelled or shell-less eggs +/- depigmentation
Adenovirus
ducks, geese, chickens
In what birds is egg drop syndrome the most severe? How was it first introduced into chickens?
broiler breeders and brown egg layer strains
through contaminated vaccine
In what 2 ways can egg drop syndrome be transmitted?
- excretion in feces
- vertical transmission (primary)
What are 3 clinical signs of egg drop syndrome? How can it be controlled?
- loss of color in pigmented eggs
- thin-shelled/shell-less eggs
- egg production drops 40%
- avoid contact of diseased with other birds
- disinfect all equipment regularly
- inactivated vaccines before egg laying begins
What is the host range of Fowl Adenovirus Inclusion Body Hepatitis? How is it transmitted?
domestic avian species of all ages, meat-type chickens
VERTICAL - stress, sex hormons
LATERAL - highest titer in feces
What is the most common clinical sign of Fowl Adenovirus Inclusion Body Hepatitis? What pathology is common?
low morbidity and sudden onset of mortality peaking 3-4 days, stopping on day 5
petechial or ecchymotic hemorrhages of liver and skeletal muscle
Where are the inclusion bodies of Fowl Adenovirus Inclusion Body Hepatitis found? What do they look like?
in hepatocyte nucleus
large, eosinophilic, rounded halo
(can occasionally be basophilic)
What causes Hydropericardium-Hepatitis Syndrome? What is the most common host? What are 3 common signs?
(Angara Disease)
Adenovirus serotype 4 and 8
3-5 week old broiler chicken
- lethargy
- ruffled feathers
- yellow mucoid droppings
What is a common secondary effect of Hydropericardium-Hepatitis Syndrome (Angara Dsease)? What are 3 common pathologies?
immunosuppression
- excessive fluid in pericardial sac (straw colored, jelly-like fluid)
- enlarged, friable liver and pale kidney with generalized congestion
- intranuclear inclusion bodies
What Adenovirus commonly causes epizootic severe disease in black tailed deer? What are 2 signs?
Cervine Adenovirus (Odocoileus Adenovirus-1)
- severe pulmonary edema
- intranuclear inclusion bodies in the lining of affecter arterioles
What is the most common microscopic finding with Adenovirus infection? What is the best way of control?
tissue damage with intranuclear inclusion bodies in infected hepatocytes
vaccination
What are 3 major problems with interpreting serology results when diagnosing Adenovirus?
- antibodies are common in healthy and diseased birds
- birds are frequently affected by a number of different serotypes
- humoral antibodies give no indication of local immunity at mucosal surface
What genus is Porcine adenovirus found in? What serotypes are of importance?
Mastadenovirus
PAdV-A serotypes 1-3
Does Porcine Adenovirus usually cause infection? What are 5 general clinical signs?
no - commonly isolated from usual GI tract flora of swine
- enteritis
- encephalitis
- nephritis
- respiratory disease
- reproductive disorders
How is Porcine Adenovirus typically detected? Is there treatment available?
- fecal and intestinal cultures using negatively stained TEM
- immunofluorescence antibody assays
- complement fixation
- direct immunofluorescence
- gel diffusion precipitation tests
no
Adenoviral conjunctivitis:
What 5 characteristics make Adenovirus a good candidate for gene therapy?
- replication deficient
- 8 kb foreign DNA
- high titer production
- infect a variety of tissues
- high expression in non-replicating tissues
