Adenoviridae Flashcards
(155 cards)
1
Q
Genus of Adenoviridae
A
Mastadenovirus
2
Q
Describe DNA of Adenovirus
A
Non-enveloped linear dsDNA
3
Q
From what tissue site was adenovirus first isolated?
A
Adenoid tissue
4
Q
In which tissues does AV replicate and produce disease?
A
RT
GIT
Urinary Tract
Eyes
5
Q
Adenovirus is a frequent cause of ASYMPTOMATIC respiratory infection that produces in vitro ___
A
Cytolysis
6
Q
Extremely hardy (3)
A
Ubiqiutous
Survives long periods outside host
Endemic throughout the year
7
Q
Shape, diameter and characteristic of virion of AV
A
Icosahedral
70 - 90 in diameter
Fibers project from each 12 vertex or penton base
252 capsomeres
8
Q
Composition of AV
A
13% DNA, 87%
9
Q
Genome of AV
A
Linear dsDNA
26 - 45 kbp
Protein bound to termini, infectious
10
Q
Important antigens of AV that are associated with major outer capsid proteins
A
Hexon
Penton base
Fiber
11
Q
Site of replication of AV
A
nucleus
12
Q
Outstanding features of AV
A
Excellent model for molecular studies of eukaryotic cell processes
13
Q
2 major proteins of AV
A
polypeptide V and polypeptide
14
Q
Pentons, hexons and fibers are important because? (3)
A
For attachment
Constitute major AV antigens
For viral classification and disease diagnosis
15
Q
Major components of the virus particles.
A
Hexon and Penton
16
Q
All himan adenoviruses display this common hexon antigenicity
A
Group and type specific epitopes on both hexon and fiber polypeptides
17
Q
Occur at the 12 vertices of the capsid and have fibers protruding from them
A
Pentons
18
Q
Carries a toxin-like activity that causes RAPID appearance of cytopathic effects and detachment of cells from the surface on which they are growing
A
Penton Base
19
Q
Another function of Penton Base aside from having a toxin-like activity
A
Exhibits a group-reactive antigen
20
Q
Contain type-specific antigens that are important in serotyping
A
Fibers
21
Q
Another function of fibers aside from serotyping
A
Associated with hemagglutinating activity, which is type-specific
22
Q
Commonly used for typing isolates in AV
A
HI tests
23
Q
True or False. AV infections occur worldwide, year-round, but do not cause community outbreaks.
A
True
24
Q
Mode of transmission of AV
A
Oral route Fecal contamination Contaminated fomites Direct contact Respiratory droplets
25
Manifestations of AV are usually...
Subclinical and non-pathognomonic
26
Highest susceptibility of AV infection is found among
children from 6 months to 2 years, extending to children 5 to 9 years old
27
most frequently isolated from adenovirus-infected children
Low-numbered respiratory types (1, 2, 3, 5, 7)
28
Gastroenteritis types
40, 41
29
Acute respiratory disease among military recruits
3, 4, 7 (although adenoviruses cause only 2-5% of all respiratory illness in the general population)
30
found in the urine of AIDS patients
Types 42, 47
31
True or False. Eye infections can be transmitted in several ways, but hand-to-eye transfer is particularly important.
True
32
Swimming pool conjunctivitis
- Outbreaks presumably waterborne, usually during summer
- Commonly caused by types
3 and 7
33
- 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
34
More recently, types ___ have caused epidemics of typical epidemic keratoconjunctivitis
19 and 37
35
Outbreaks of Epidemic keratoconjunctivitis traced to?
traced to ophthalmologists’ offices were presumably caused by contaminated ophthalmic solutions or diagnostic equipment
36
found most often in bone marrow and renal transplant recipients
Types 34 and 35
37
Most likely source of types 34 and 35 AV infection
Endogenous viral reactivation
38
Types 34 and 35 AV infection reported incidence higher in which population?
Pediatric
39
Frequency of occurrence during first years of life
Types 1, 2, 5, 6
40
Frequency of occurrence during school years
Types 3, 7
41
Frequency of occurence during adulthood
Types 4, 8, 19 (and others)
42
How many types and subgroups were identified in human adenoviruses?
47 types, 6 subgroups
43
Genus that infects birds
Aviadenovirus
44
Genus that infects mammals
Mastadenovirus
45
Members of a given adenovirus group resemble one another in the ____ of their DNA
guanine-plus-cytosine content
46
Regularly isolated from feces of healthy humans (GIT infection without manifestations)
Group A
Type 12
18
31
47
Isolated from throat washings of patients during epidemics of acute respiratory illness
Group B
| Type 3, 7, 11, 14, 16, 21, 34, 35
48
From gastrointestinal and respiratory tracts of children with mild upper respiratory tract infections
```
Group C
Type 1
2
5
6
```
49
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
50
Associated with severe respiratory tract disease in both sporadic and epidemic forms with pharyngoconjunctival fever (RT)
Group E type 4
51
Enteric (GIT infection with manifestation)
Group F Type 40, 41
52
May be associated with severe pneumonia (RT)
Group B
| Type 3, 7, 11, 14, 16, 21, 34, 35
53
Also isolated from adenoids and tonsillar tissues (lymphoid tissue)
```
Group C
Type 1
2
5
6
```
54
AV infect and replicate in cells of ____ and do not spread beyond the _____
epithelial origin
| regional lymph nodes
55
AV infection shed in ___
feces
56
Virus produces ___ in various tissues and induces inflammatory responses and cytokine production
cytolysis
57
AV infection is overt or not?
Overt
58
Virus enters human epithelial cells and continues through entire replication. Results in host cell death.
Lytic Infection
59
Mechanism unknown
| Asymptomatic infection of lymphoid tissue
Chronic, latent infection
60
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
61
Viral DNA integrated into host cell DNA
Produces specific proteins that immortalize rodent cells
Oncogenic transformation
62
Replicative cycle is sharply divided into
early and latent events
63
Adenovirus infectious cycle takes about
24 hours
64
about ____ virus particles are produced per cell
100,000
65
Time between AV infection and the first appearance of progeny virus is the ____
Eclipse period
66
A measure of infectious virus
Plaque-Forming Unit
67
AC attachment via the ____; host cell receptor for some serotypes is ____, a member of the immunoglobulin gene superfamily
fiber structures
CAR (coxsackie-adenovirus receptor)
68
Interaction of the ____ following attachment promotes internalization
penton base with cellular integrins
69
True or False. Adsorption and internalization are separate steps in the infectious process.
True
70
an organized, sequential process that systematically breaks down the stabilizing interactions that were established during maturation of the virus particle
Uncoating
71
Adsorbed virus is internalized into ____
endosomes
72
Majority of the particles (~90%) move rapidly from endosomes into cytosol (t1/2=5 minutes), triggered by the ___ of the endosome
acidic pH
73
Transport of virus particles across cytoplasm to the nucleus by ____
Microtubules
74
Uncoating commences in the _____ and completed in the ____; release of DNA perhaps occurring at the _____
cytoplasm
nucleus
nuclear membrane
75
Events in the nucleus
Viral replication
Viral assembly (virion morphogenesis)
Mature particle is stable, infectious and resistant to nucleases
76
Steps that occur before the onset of viral DNA synthesis
Early events
77
GOALS OF EARLY EVENTS
Induce the host cell to enter the S phase of the cell cycle to create conditions conducive to viral replication
Express viral functions that protect infected cell from host defense mechanisms
Synthesize viral gene products needed for viral DNA replication
78
must be expressed in order for other early regions to be transcribed
E1A early gene
79
Functions to modulate the cell cycle
E1A gene products
80
Encodes proteins that block apoptosis that occurs due to E1A functions
Necessary to prevent premature cell death that would adversely affect virus yields
E1B early region
81
Contain the only adenovirus genes involved in cell transformation; gene products bind up cellular proteins (eg, pRb, p300, p53) that regulate cell cycle progression
E1A, E1B regions
82
virus-encoded, covalently linked terminal protein functions as a ____
primer for initiation of viral DNA synthesis
83
Late events begin concomitantly with ___
onset of viral DNA synthesis
84
Where the viral proteins are synthesized
Cytoplasm
85
Although host genes continue to be transcribed in the nucleus late in the course of infection, few host genetic sequences are transported to the cytoplasm. True or False.
True
86
A complex involving the ____ inhibits the cytoplasmic accumulation of cellular mRNAs
E1B 55-kDa polypeptide and the E4 34-kDa polypeptide
87
Virion morphogenesis occurs in the ____
nucleus
88
trimer of identical polypeptides
Hexon Capsomere
89
composed of five (5) penton base polypeptides and three (3) fiber polypeptides
Penton
90
Late L4-encoded, assists in the aggregation of hexon polypeptides but is not part of the final structure
Scaffold protein
91
Capsomeres self-assemble into _____
empty-shell capsids in the nucleus
92
____ enters preformed capsid
Naked DNA
93
serves as a packaging signal, necessary for the DNA-capsid recognition event
cis-acting DNA element near the left-hand end of the viral chromosome
94
Another viral scaffolding protein, encoded in the ____, facilitates DNA encapsidation
L1 group
95
Precursor core proteins are cleaved, which allows the particle to ____, and the pentons are added
tighten its configuration
96
A virus-encoded _____ functions in some cleavages of precursor proteins
cysteine proteinase
97
Mature particle is then stable, infectious, and resistant to _____
Nucleases
98
Afford protection from the antiviral effect of interferon by preventing activation of an interferon-inducible kinase that phosphorylates and inactivates eukaryotic initiation factor 2
Small, abundant VA RNAs
99
Nonessential for viral growth in tissue culture; inhibit cytolysis of infected cells by host responses
Adenovirus E3 region proteins
100
Blocks movement of the MHC class I antigen to the cell surface, protecting the infected cell from cytotoxic T lymphocyte (CTL)-mediated lysis
E3 gp19-kDa protein
101
Block induction of cytolysis by TNF-alpha
E3-encoded proteins
102
Cells infected with adenovirus have an affinity for which stain?
haematoxylin (a purplish-blue dye)
103
Infected cells become ____ and the cell sheet _____ during staining.
rounded
disintegrates
104
Dark basophilic inclusions within the nuclei represent __________.
accumulated viral proteins at the site of virus assembly
105
Cytopathic effect of adenoviruses:
marked rounding, enlargement aggregation of affected cells into grape-like structures with inclusion bodies (intranuclear, with DNA) and crystal structures
106
Virus particles in the nucleus exhibit ______ that do not contain nucleic acid
crystal line arrangements- proteins
107
AV infected cell lyse. True or False.
False. Infected cells do not lyse.
108
Virus particles remain in the cell after the cycle is complete and the cell is dead. True or False.
True
109
Tissue used for AV culture
primary kidney and continuous epithelial cells
110
Among military recruits
Characterized by fever, sore throat, nasal congestion, cough, and malaise, sometimes leading to pneumonia
Occurs in epidemic form among young military recruits under conditions of fatigue, stress, and crowding soon after induction
Caused by types 4 and 7
Acute respiratory disease syndrome
111
Adenovirus may also be isolated from children with _____ (ARDS)
whooping cough
112
LRT adeno infections may mimic _____.
RSV
113
Tends to occur in outbreaks (children's summer camps)
Pharyngoconjunctival fever
114
Associated with bathing in inadequately chlorinated water source such as pool or lake
Swimming pool conjunctivitis
115
Classic presentation of Pharyngoconjunctival fever
fever, sore throat, coryza, red eyes
116
PE findings in Pharyngoconjunctival fever
pharyngitis (may be exudative)
| headache, cervical lymphadenopathy
117
Hallmark of Pharyngoconjunctival fever
Perinaud syndrome (pre-auricular lymphadenopathy)
118
Duration of Pharyngoconjunctival fever
1–2 weeks, usually self-limiting (5 days)
119
Outcome ofPharyngoconjunctival fever
Complete recovery with no lasting sequelae is the common outcome (Uncommonly, exanthema and diarrhea may occur)
120
Transmitted via hands and fomites; also through instrumentation, industrial trauma, contaminated ophthalmic solutions.
Epidemic keratoconjunctivitis
121
Characterized by acute conjunctivitis, followed by keratitis that usually resolves in 2 weeks but may leave subepithelial opacities in the cornea for up to 2 years
Epidemic keratoconjunctivitis
122
Other complications of Epidemic keratoconjunctivitis
Palpebral edema is present, hemorrhagic conjunctivitis may develop
123
Epidemic keratoconjunctivitis caused by?
types 8, 19, and 37
124
Affects children aged 5 – 15 yrs, but immunocompromised adults can also be affected (males>females)
Caused by serotypes 11 and 21
Acute Hemorrhagic Cystitis
125
Findings in Acute Hemorrhagic Cystitis
Dysuria, frequency and gross blood in urine
Hematuria self-limiting; usually up to 3 days
126
Serotypes etiologically associated with infantile gastroenteritis
Serotypes 40 and 41
127
Most commonly affected intestinal area in nonenteric adenovirus infection and intusussception
junction of ileum and cecum
128
Adenovirus types 40 and 41 are abundantly present in what specimens?
Diarrheal stools
129
Adenovirus gastroenteritis s/sx is self-limited.True or false?
True. Fever and watery stool usually limited, 1-2 weeks
130
Most common problem in transplant patients
Respiratory disease
131
Patients with acquired immunodeficiency syndrome (AIDS) may suffer adenovirus infections, especially in the?
GIT
132
In contrast to most respiratory infectious agents, adenoviruses induce effective and long-lasting immunity against reinfection. True or False.
True
133
Resistance to clinical disease directly related to the presence of _____, which probably persist for life
circulating neutralizing antibodies
134
Maternal antibodies usually protect infants against severe adenovirus respiratory infections. True or False.q
True
135
GROUP-REACTIVE ANTIBODY RESPONSE may be measured by ______
CF, IF, or ELISA testing
136
GROUP-REACTIVE ANTIBODY RESPONSE:
- -Are not protective and decline with time
- Do not reveal the serotypes of previous viral infections
True
137
Lab diagnosis: stable in routine viral transport medium. True or False.
True
138
RECOMMENDED TIMING OF COLLECTION:
| Throat of adults with common colds
1-3 days
139
RECOMMENDED TIMING OF COLLECTION:
| Throat, stool and eye for pharyngoconjunctival fever
3-5 days
140
RECOMMENDED TIMING OF COLLECTION:
| Eye for keratoconjuctivitis
2 weeks
141
RECOMMENDED TIMING OF COLLECTION:
| Throat and stool with children with respiratory illness
3 - 6 weeks
142
RECOMMENDED TIMING OF COLLECTION:
| Urine, throat and stool of immunocompromised patients
2 - 12 months
143
Serology test:
For detecting infection by any member of the adenovirus group
A fourfold or greater rise in complement-fixing antibody titer between acute-phase and convalescent-phase sera indicates recent infection with an adenovirus
Gives no clue about the specific type involved
CF Test
144
Tests for ARD
Nasopharyngeal swab for culture
Consider monospot test
Throat swab and culture to rule out streptococcal infection
145
Tests for Pharyngoconjunctival fever
Nasopharyngeal swab for culture of respiratory viruses
Consider rapid Group A streptococcus throat swab and culture
146
Viral isolation
Primary human embryonic kidney cells
Human epithelial cell lines (Hep-2, HeLa and KB)
147
Increased glycolysis in cells in viral isolation
Growth medium highly acidic on infected cultures
148
Isolates can be identified as adenoviruses by ______ using an antihexon antibody and infected cells
immunofluorescence tests
149
Rapid viral detection usiing?
Shell Vial Technique
150
diagnosis of adenovirus infections in tissue samples or body fluids
PCR
151
Characterization of viral DNA by?
hybridization or by restriction endonuclease digestion patterns (for types that are difficult to cultivate)
152
Has been used in patients who have undergone hematopoietic stem cell transplants.
Ribavirin
153
Used with limited success in the tx of AV
Cidofovir
154
Environmental surfaces can be disinfected with?
sodium hypochlorite
155
Live adenovirus vaccine containing _____, encased in gelatin-coated capsules and given orally, was introduced in 1971.
types 4 and 7
