Adenoviridae Flashcards
Genus of Adenoviridae
Mastadenovirus
Describe DNA of Adenovirus
Non-enveloped linear dsDNA
From what tissue site was adenovirus first isolated?
Adenoid tissue
In which tissues does AV replicate and produce disease?
RT
GIT
Urinary Tract
Eyes
Adenovirus is a frequent cause of ASYMPTOMATIC respiratory infection that produces in vitro ___
Cytolysis
Extremely hardy (3)
Ubiqiutous
Survives long periods outside host
Endemic throughout the year
Shape, diameter and characteristic of virion of AV
Icosahedral
70 - 90 in diameter
Fibers project from each 12 vertex or penton base
252 capsomeres
Composition of AV
13% DNA, 87%
Genome of AV
Linear dsDNA
26 - 45 kbp
Protein bound to termini, infectious
Important antigens of AV that are associated with major outer capsid proteins
Hexon
Penton base
Fiber
Site of replication of AV
nucleus
Outstanding features of AV
Excellent model for molecular studies of eukaryotic cell processes
2 major proteins of AV
polypeptide V and polypeptide
Pentons, hexons and fibers are important because? (3)
For attachment
Constitute major AV antigens
For viral classification and disease diagnosis
Major components of the virus particles.
Hexon and Penton
All himan adenoviruses display this common hexon antigenicity
Group and type specific epitopes on both hexon and fiber polypeptides
Occur at the 12 vertices of the capsid and have fibers protruding from them
Pentons
Carries a toxin-like activity that causes RAPID appearance of cytopathic effects and detachment of cells from the surface on which they are growing
Penton Base
Another function of Penton Base aside from having a toxin-like activity
Exhibits a group-reactive antigen
Contain type-specific antigens that are important in serotyping
Fibers
Another function of fibers aside from serotyping
Associated with hemagglutinating activity, which is type-specific
Commonly used for typing isolates in AV
HI tests
True or False. AV infections occur worldwide, year-round, but do not cause community outbreaks.
True
Mode of transmission of AV
Oral route Fecal contamination Contaminated fomites Direct contact Respiratory droplets
Manifestations of AV are usually…
Subclinical and non-pathognomonic
Highest susceptibility of AV infection is found among
children from 6 months to 2 years, extending to children 5 to 9 years old
most frequently isolated from adenovirus-infected children
Low-numbered respiratory types (1, 2, 3, 5, 7)
Gastroenteritis types
40, 41
Acute respiratory disease among military recruits
3, 4, 7 (although adenoviruses cause only 2-5% of all respiratory illness in the general population)
found in the urine of AIDS patients
Types 42, 47
True or False. Eye infections can be transmitted in several ways, but hand-to-eye transfer is particularly important.
True
Swimming pool conjunctivitis
- Outbreaks presumably waterborne, usually during summer
- Commonly caused by types
3 and 7
- Caused by type 8 adenovirus
- Spread in 1941 from Australia via the Hawaiian Islands to the Pacific Coast
- Spread rapidly through shipyards (hence, the disease was also called shipyard eye) and across the US
Epidemic keratoconjunctivitis
More recently, types ___ have caused epidemics of typical epidemic keratoconjunctivitis
19 and 37
Outbreaks of Epidemic keratoconjunctivitis traced to?
traced to ophthalmologists’ offices were presumably caused by contaminated ophthalmic solutions or diagnostic equipment
found most often in bone marrow and renal transplant recipients
Types 34 and 35
Most likely source of types 34 and 35 AV infection
Endogenous viral reactivation
Types 34 and 35 AV infection reported incidence higher in which population?
Pediatric
Frequency of occurrence during first years of life
Types 1, 2, 5, 6
Frequency of occurrence during school years
Types 3, 7
Frequency of occurence during adulthood
Types 4, 8, 19 (and others)
How many types and subgroups were identified in human adenoviruses?
47 types, 6 subgroups
Genus that infects birds
Aviadenovirus
Genus that infects mammals
Mastadenovirus
Members of a given adenovirus group resemble one another in the ____ of their DNA
guanine-plus-cytosine content
Regularly isolated from feces of healthy humans (GIT infection without manifestations)
Group A
Type 12
18
31
Isolated from throat washings of patients during epidemics of acute respiratory illness
Group B
Type 3, 7, 11, 14, 16, 21, 34, 35
From gastrointestinal and respiratory tracts of children with mild upper respiratory tract infections
Group C Type 1 2 5 6
Associated with conjunctivitis and pharyngoconjunctival fever (eye)
Group D
Type 8, 9, 10, 13, 15, 17, 19, 20, 22-30, 32, 33,36-39, 42-47
Associated with severe respiratory tract disease in both sporadic and epidemic forms with pharyngoconjunctival fever (RT)
Group E type 4
Enteric (GIT infection with manifestation)
Group F Type 40, 41
May be associated with severe pneumonia (RT)
Group B
Type 3, 7, 11, 14, 16, 21, 34, 35
Also isolated from adenoids and tonsillar tissues (lymphoid tissue)
Group C Type 1 2 5 6
AV infect and replicate in cells of ____ and do not spread beyond the _____
epithelial origin
regional lymph nodes
AV infection shed in ___
feces
Virus produces ___ in various tissues and induces inflammatory responses and cytokine production
cytolysis
AV infection is overt or not?
Overt
Virus enters human epithelial cells and continues through entire replication. Results in host cell death.
Lytic Infection
Mechanism unknown
Asymptomatic infection of lymphoid tissue
Chronic, latent infection
persist as latent infections for years in adenoids and tonsils and are shed in the feces for many months after the initial infection
Group C viruses
Viral DNA integrated into host cell DNA
Produces specific proteins that immortalize rodent cells
Oncogenic transformation
Replicative cycle is sharply divided into
early and latent events