Adenoviridae Flashcards
Adenoid
Made up of lymphatic tissue, traps and destroys pathogens in the air that enter the nasopharynx
Adenovirus
- many serotypes
- highly host specific
- isolated from humans, animals, birds
- mainly produce subclinical infections
Where is adenovirus isolated from?
Usually from the upper respiratory tract, but sometimes the feces
Adenoviruses usually produce mild infections, except with:
Avian adenoviruses
- associated with a variety of syndromes
Adenovirus - general characteristics
- icosahedral virion
- 70-90 nm diameter
- replicate in nucleus of cells
- virions released by cell lysis
Adenovirus genome
Linear dsDNA, 30-37 kbp in size
Adenovirus pathogenesis
Produce intranuclear inclusion bodies containing virions
- agglutinate RBCs: tips of the fiber bind to a receptor on the surface of the RBC
- some adenoviruses are oncogenic in mice
What is a good diagnostic test for adenoviruses?
Hemagglutination inhibition test
- provides simplest assay for virus or antibody detection
- virus is host specific, need to use species specific blood for hemagglutination tests
Hemagglutination inhibition test
Virus, RBCs, and antibody from the serum
- look at how high the titer is
- if the antibody is for the virus, then you will have antigen-antibody binding –> virus no longer has capability to bind to the RBCs so you will see a button, not a layer of RBC
What is the component that is able to bind to the cell receptor?
Fiber
Classification of adenovirus is based on:
Antigenic relationships
How many genera is apart of the adenovirus family?
Mastadenovirus (mammalian) and Aviadenovirus (avian)
- the 2 genera do not share a common group antigen
- genus-specific antigenic determinants on the pentamers
- type-specific antigenic determinants (defined by neutralization and HI assays) are located on the hexamers and fibers
What is the antigenic component of adenoviridae?
Pentamers
Horse
- 2 serotypes
- asymptomatic or mild upper respiratory disease in foals with congenital immunodeficiency
Cattle, swine, sheep, goat
Usually asymptomatic or mild upper respiratory disease
- cattle: 10 serotypes
- swine: 4 serotypes
- sheep: 6 serotypes
- goat: 2 serotypes
Dog
- 2 serotypes
- infectious canine hepatitis (type 1), infectious canine tracheobronchitis (type 2)
Chicken
- 12 serotypes
- rarely, inclusion body hepatitis and egg drop syndrome
Turkey
- 3 serotypes
- bronchitis, marble spleen disease, enteritis, egg drop syndrome
Duck
- 2 serotypes
- rarely, duck hepatitis
Quail
Bronchitis
Goose
- 3 serotypes
- isolated from liver, intestine
Viral replication
Mature virus –> attachment –> pentons, rupture of the phagocytic membrane –> hexons –> core enters nucleus, DNA is released
Adenovirus causes ____, ______, or ______ respiratory disease
Acute, mild or subclinical
- confined to URT, may include conjunctivitis and bronchopneumonia
- may have mild or subclinical gastroenteric disease
- hepatitis
Adenoviruses can be recovered from the _______
Lymphoid organs of healthy animals
- long periods of latency
In what scenario is adenovirus pathogenic?
- to immunodeficient animals
- generalized infections in Arabian foals with primary severe combined immunodeficiency
- when avian immune systems are compromised by avian leukosis, infectious bursal disease or chicken anemia
Chicken anemia attacks the _____
Thymus
Canine adenovirus infections
- canine adenovirus 1: respiratory or ocular disease, encephalopathy, chronic hepatitis and nephritis
- canine adenovirus 1 + 2: related to kennel cough
- canine adenovirus 2: respiratory disease, tonsillitis, pharyngitis, tracheitis, bronchitis, bronchopneumonia
Which type of adenovirus is less severe?
Type 2
Canine adenovirus 1
Causes infectious canine hepatitis (ICH)
- rare, due to widespread vaccination
- majority are asymptomatic
- susceptible dogs characterized by fever, hepatic necrosis, widespread hemorrhages as a consequence of vascular injury
Infectious canine hepatitis
- increase thirst
- anorexia
- tonsillitis
- petechial hemorrhages on mucous membranes
- diarrhea
- may develop conjunctivitis and photophobia
- severe ICH is most likely to occur in pups that are not immune to disease
Blue eye is caused by ______
Canine adenovirus 1
- results from corneal edema
- convalescent stages of natural infection
- 8-12 days after vaccination with attenuated live canine adenovirus 1
Vaccines
- Killed + attenuated live: available for canine adenovirus 1
- attenuated live: canine adenovirus 2
T/F: antigenic relationship between adenovirus 1 and 2 is sufficiently close
True
- canine adenovirus 2 vaccine can cross protect and does not cause corneal edema
Laboratory diagnosis
Confirmed by serologic testing –> complement fixation, hemagglutination inhibition, ELISA
- PCR to detect viral nucleic acid
- virus isolation
- immunohistochemical staining of tissues with CAV-1 antibody
Canine adenovirus 2
Isolated from acute cough
- one of agents implicated in kennel cough
- experimental infection produced pharyngitis, tonsillitis, and tracheobronchitis
- virus persists in respiratory tract for up to 28 days (very long time)
Canine adenovirus 2 does not produce ______ and _____
Renal and ocular lesions
Bovine adenoviruses
10 serotypes
- only produce mild symptoms
- pneumonia, enteritis in young or immunosupressed cattle
Which 2 serotypes of bovine adenovirus are more pathogenic?
BAV 3 and BAV 5
Does bovine adenovirus have a vaccine?
None licensed in the US
Equine adenovirus infections
Arabian foals suffer from primary severe combined immunodeficiency disease = absence of both T and B cells making them susceptible
- maternal antibody wanes
- occurs within 3 months of age
Which adenovirus is the main pathogen of equine adenovirus?
Type 1
- causes bronchitis, pneumonia
- invades a wide range of tissues
Is equine adenovirus a genetic disease?
Yes, infects Arabians
Avian adenovirus infections
- group 1: share a common antigen, isolated from chickens, turkeys, and geese
- group 2: share a different antigen, include viruses from turkey hemorrhagic enteritis, marble spleen disease, splenomegaly in chicken
- group 3: partially antigenically related to group 1 viruses, associated with egg drop syndrome in chickens and ducks
Does group 1 share any common antigens with group 2?
No
- does not cross react
Avian adenoviruses produce subclinical infections in _________
Breeding flocks and contaminate eggs
Avian live virus vaccines
Want to use adenovirus contaminated cells to produce avian-live virus vaccines
- chicken embryos origin cell cultures used as substrate for production of vaccines
______ can be used as a vector to carry another viral gene
Adenovirus
Laboratory diagnosis
Inoculation of fecal samples or tissue homogenates into cell cultures derived from homologous species
- cytopathic changes evident on first passage
- some enteric adenoviruses are difficult to grow in cell cultures
- HI and neutralization assays are used for typing viral isolates
Which is easier to perform, HI or neutralization?
HI
- neutralization requires cell cultures
