Week 2: Laboratory detection of viruses Flashcards
1
Q
How does serology work in detecting viruses?
A
Detection of antibodies developed against virus
2
Q
Advantages of serology for virus detection
A
Can detect acute and past infections
3
Q
Disadvantages of serology for virus detection
A
Delay time due to time to develop antibodies
4
Q
When to use serology for the detection of viruses
A
With viruses unable or difficult to culture
5
Q
How does viral culture work in detecting viruses?
A
Detection of cytopathic effect of virus on cells
6
Q
Advantages of viral culture for viral detection
A
Inexpensive
7
Q
Disadvantages of viral culture for viral detection
A
Time consuming
8
Q
When to use Viral culture for the detection of viruses?
A
Emergence of new viruses
9
Q
How does detection of viral antigens work in viral detection?
A
Detection of specific viral antigens either immunoassay or fluorescent
10
Q
Advantages of detection of viral antigens for viral detection
A
Inexpensive
Rapid
Specific
11
Q
Disadvantages of detection of viral antigens for viral detection
A
Lack of sensitivity
12
Q
When to use detection of viral antigens for viral detection
A
When rapid diagnosis is needed
13
Q
How molecular detection works in viral detection?
A
Nucleic acid amplification detection of specific genetic target
14
Q
Advantages of molecular detections for viral detection
A
High sensitivity
High specificity
15
Q
Disadvantages of molecular detections for viral detection
A
Expensive
Must know the target of interest
16
Q
When to use molecular detection for viral detection
A
When accurate diagnosis is necessary
17
Q
Describe the considerations of specimen procurement and handling
A
- Highest yields from early collection during acute phase of infection
- Prolonged shedding in immunocompromised patients
- Typical acceptable volumes 2-3 mL
- Stabilize virus in transport medium (exceptions: urine specimens and specimens for EM)
- Time = virus
- Transport to the lab immediately
- Keep specimen cold but do not freeze (0-4 oC)
- Refrigerate specimen if transport is delayed (exception: blood for CMB antigenemia testing)
18
Q
Case 1
A
19
Q
Describe the importance of major respiratory viruses in common disease syndromes
A
20
Q
What is the method of detecting respiratory viral antigens
A
immunoassay
21
Q
Method of influenza and RSV detection
A
22
Q
Describe the method of detecting respiratory viruses
A
23
Q
What does a fluorescent respiratory panel look like?
A
24
Q
Describe the seasonality of respiratory viruses
A
25
Case 2
26
Describe the main applications of serologic diagnosis of viral infections
* Diagnosis of recent or chronic viral infections (eg hepatitis)
* Determination of immune status to a specific virus in a person or population (eg varicella)
* Verify immune response to vaccination (eg rubella, measels, smallpox, many others)
* Also, resolve diagnostic uncertainties
* virus not detectable by other methods
* Proper specimens for culture or direct detection are unavailable
* Specimens collected too late in the disease course
* Virus has been identified but the causal role in the disease process is unclear
27
Describe the interpretation of viral serological test results
28
What is the standard approach to HBV serological testing
29
HBV test results interpretation
30
Question
31
Factors that may complicate interpretation of viral serologies
32
More factors that may complicate the interpretation of viral serologies
33
Viruses for which Ab detection & Quantitation are key methods of laboratory diagnosis
13 listed
34
Case 3
35
General considerations of CSF
36
Describe the mechanism of replication in PCR
37
Agents of CNS viral infections
38
Viral encephalitis clue:
Temporal lobe localization
HSV
39
Viral encephalitis clue:
animal bite or bat exposure
Rabies
40
Viral encephalitis clue:
exposure to mice or hamsters
LCMV
41
Viral encephalitis clue:
Summer or fall onset
* Arboviruses
* Enteroviruses
42
Viral encephalitis clue:
fall or winter onset
LCMV
43
Viral encephalitis clue:
Rash
* Enteroviruses
* HHV-6
* Measels
* Rubella
* VZV
44
Viral encephalitis clue:
Parotitis/Orchitis
Mumps
45
What is Parotitis?
an inflammation of one or both parotid glands, the major salivary glands located on either side of the face, in humans. The parotid gland is the salivary gland most commonly affected by inflammation
46
What is orchitis?
is an inflammation of the testicles. It can be caused by either bacteria or a virus. Both testicles may be affected by orchitis at the same time. However, the symptoms usually appear in just one testicle. This kind of testicular inflammation is often associated with the mumps virus.
47
Viral encephalitis clue:
Concurrent or recent chicken pox or shingles
VZV
48
Viral encephalitis clue:
recent respiratory illness
* Influenza
* parainfluenza
* adenovirus
49
Viral encephalitis clue:
IM-like illness
* EBV
* CMV
* HIV
50
Viral encephalitis clue:
HIV risk factors
* HIV
* Herpesviruses
* JC virus
51
Viral encephalitis clue:
Immunosuppression
* Herpesviruses
* JC virus
* Measles
* Adenovirus
52
Case 4
53
Herpesviruses that infect humans
54
HHV-1 AKA
Herpes simplex virus 1
55
HHV-2 AKA
Herpes Simplex virus 2
56
HHV-3 AKA
Varicella-Zoster Virus
57
HHV-4 AKA
Epstein-Barr Virus
58
HHV-5 AKA
Cytomegalovirus
59
HHV-6 AKA
HHV-6
60
HHV-7 AKA
HHV-7
61
HHV-8 AKA
Kaposi's Sarcoma Herpesvirus
62
Herpesvirus simiae; Cercopthicine HV 1 AKA
Herpes B virus
63
Herpes simplex virus 1 sub-family
α
64
Herpes simplex virus 2 sub-family
α
65
Varicella-Zoster virus subfamily
α
66
Epstein-Barr Virus sub-family
γ
67
Cytomegalovirus sub-family
β
68
HHV-6 Sub-family
β
69
HHV-7 sub-family
β
70
Kaposi's Sarcoma Herpesvirus sub-family
γ
71
Herpesvirus simiae; cercopithicine HV-1 or Herpes B virus sub-family
α
72
Herpes simplex virus 1 cellular receptor
* Heparan sulfate
* Nectin 1
* Nectin 2
* HVEM
73
Herpes simplex virus 2 cellular receptor
Heparan sulfate
Nectin 1
Nectin 2
HVEM
74
Varicella-Zoster virus cellular receptors
?
75
Epstein-Barr virus cellular receptors
Complement receptor 2 (CD21)
76
Cytomegalovirus cellular receptors
* Heparan sulfate
* integrins α2β1
* Integrins α6β1
* Integrins αvβ3
* PDGF-α receptor
77
HHV-6 cellular receptor
?
78
HHV-7 cellular receptor
?
79
Kaposi's Sarcoma Herpesvirus cellular receptors
Integrin α3β1
80
Herpesvirus simiae; cercopithicine HV-1 cellular receptors
?
81
Describe the method of diagnosis of herpesvirus infections
82
Describe HSV CPE in epithelial cells
83
Pap-stained smear from HSV Vulvar Ulceration
84
Case 5
85
Histology of CMV infection of Pneumocytes
86
What are the non-histologic methods of CMV detection
* Conventional Cx
* Shell vial Cx
* Antigenemia
* PCR
87
Conventional Cx advantages
* specific
* multiple specimen types
* Isolates for further testing
88
Conventional Cx disadvantages
* Slow (usually 7-21 days)
* requires virus viability
* suboptimal for blood
89
Shell vial Cx advantages
* Rapid (24-48 hours)
* Multiple specimen types
90
Shell vial Cx disadvantages
* Requires virus viability
* interference from cytotoxicity
* suboptimal for blood
* Sensitivity may be lower than traditional Cx
91
Antigenemia advantages
* Rapid (2-4 hours)
* Sensitive
* Quantitative
* Viable virus not required
* Systemic Dz monitoring
92
Antigenemia disadvantages
Antigen unstable with ex-vivo storage
93
PCR advantages for virus detection
* sensitive
* Viable virus not required
* Systemic Dz monitoring
* Stable target
* Can be made quantitative
94
PCR disadvantages for virus detection
quantitative assay may be too sensitive for clinical utility
95
CMV cytopathicity in human fibroblasts
* Very focal CPE
* slow progression
* "Fusiform splitting" of the monolayer by infected cells
* Efficient viral growth only in fibroblasts of human origin
* Human diploid fibroblasts used exclusively for diagnostic purposes
96
Shell vial culture fluorescence antibody staining using CMV-immediate-early protein
97
Community-acquired CMV clinical syndromes in fetus and newborn by intrauterine transmission
Congenital CMV infection with CNS disease, hepatitis and thrombocytopenia
98
Community-acquired CMV clinical syndromes in fetus and newborn by intrapartum transmission
Asymptomatic infection with CNS sequelae (hearing-loss)
99
Community-acquired CMV clinical syndromes in fetus and newborn by breast-milk transmission
Asymptomatic infection with prolonged shedding
100
Community-acquired CMV clinical syndromes in children by saliva transmission
Asymptomatic infection
101
Community-acquired CMV clinical syndromes in children by urine transmission
Infrequent IM-like syndrome
102
Community-acquired CMV clinical syndromes in adolescents and young adults by saliva transmission
IM syndrome
103
Community-acquired CMV clinical syndromes in adolescents and young adults by sexual transmission
Asymptomatic infection
104
Iatrogenic CMV clinical syndromes in blood transfusion recipients by leukocyte transmission
IM syndrome with more severe symptoms
105
Iatrogenic CMV clinical syndromes in transplant recipients by CMV in allograft transmission
IM syndrome
106
Iatrogenic CMV clinical syndromes in transplant recipients by Blood transfusion transmission
* Leukopenia and thrombocytopenia
* Hepatitis
* Colitis
* Pneumonia
* Chronic graft rejection
107
Case 6
How would you identify this infection?
108
Specific agents of viruses readily isolated in cell culture of Herpesviruses
* Herpes simplex 1 and 2
* Varicella-Zoster
* Cytomegalovirus
109
Specific agents of viruses readily isolated in cell culture of Adenovirus
All except enteric stains (40, 41)
110
Specific agents of viruses readily isolated in cell culture of Enterovirus
* Echovirus
* Coxsackie B
* Poliovirus
111
Specific agents of viruses readily isolated in cell culture of Orthomyxoviruses
Influenza A and B
112
Specific agents of viruses readily isolated in cell culture of Paramyxoviruses
* Parainfluenza
* Respiratory syncytial virus
* Human metapneumovirus
* Mumps
* Measles
113
Specific agents of viruses readily isolated in cell culture of Rhinovirus
All strains
114
Viruses that are impractical or impossible to isolate and culture-specific agents of Hepatitis
* A
* B
* C
* D
* E
* G
115
Viruses that are impractical or impossible to isolate in culture-specific agents of Gastroenteritis
* Rotavirus
* Calcivirus (eg norwalk)
* Astrovirus
116
Viruses that are impractical or impossible to isolate in culture-specific agents of Herpesviruses
* EBV
* HHV-6/7
* KSHV
117
Viruses that are impractical or impossible to isolate in culture-specific agents of Coronaviruses
All respiratory strains (incl. SARS)
118
Viruses that are impractical or impossible to isolate in culture-specific agents of Parvovirus
B19
119
Viruses that are impractical or impossible to isolate in culture-specific agents of Retroviruses
* HTLV 1 and 2
* HIV 1 and 2
120
Viruses that are impractical or impossible to isolate in culture-specific agents of Papovaviruses
* Human pailloma
* JC polyoma
* BK polyoma
121
Viruses that are impractical or impossible to isolate in culture-specific agents of Arenaviruses
Lymphocytic chorionic meningitis virus
122
Viruses that are impractical or impossible to isolate in culture-specific agents of Arboviruses
* Many examples
* eg West Nile
123
Viruses that are impractical or impossible to isolate in culture-specific agents of Acute hemorrhagic fever viruses
* Many examples
* eg Ebola
124
Describe virus isolation using cell culture tubes
125
Shell vial virus isolation
126
Comparing virus discovery options
