Week 2: Laboratory detection of viruses Flashcards

1
Q

How does serology work in detecting viruses?

A

Detection of antibodies developed against virus

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2
Q

Advantages of serology for virus detection

A

Can detect acute and past infections

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3
Q

Disadvantages of serology for virus detection

A

Delay time due to time to develop antibodies

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4
Q

When to use serology for the detection of viruses

A

With viruses unable or difficult to culture

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5
Q

How does viral culture work in detecting viruses?

A

Detection of cytopathic effect of virus on cells

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6
Q

Advantages of viral culture for viral detection

A

Inexpensive

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7
Q

Disadvantages of viral culture for viral detection

A

Time consuming

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8
Q

When to use Viral culture for the detection of viruses?

A

Emergence of new viruses

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9
Q

How does detection of viral antigens work in viral detection?

A

Detection of specific viral antigens either immunoassay or fluorescent

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10
Q

Advantages of detection of viral antigens for viral detection

A

Inexpensive

Rapid

Specific

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11
Q

Disadvantages of detection of viral antigens for viral detection

A

Lack of sensitivity

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12
Q

When to use detection of viral antigens for viral detection

A

When rapid diagnosis is needed

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13
Q

How molecular detection works in viral detection?

A

Nucleic acid amplification detection of specific genetic target

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14
Q

Advantages of molecular detections for viral detection

A

High sensitivity

High specificity

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15
Q

Disadvantages of molecular detections for viral detection

A

Expensive

Must know the target of interest

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16
Q

When to use molecular detection for viral detection

A

When accurate diagnosis is necessary

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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)
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18
Q

Case 1

A
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19
Q

Describe the importance of major respiratory viruses in common disease syndromes

A
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20
Q

What is the method of detecting respiratory viral antigens

A

immunoassay

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21
Q

Method of influenza and RSV detection

A
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22
Q

Describe the method of detecting respiratory viruses

A
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23
Q

What does a fluorescent respiratory panel look like?

A
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24
Q

Describe the seasonality of respiratory viruses

A
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25
Q

Case 2

A
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26
Q

Describe the main applications of serologic diagnosis of viral infections

A
  • 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
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27
Q

Describe the interpretation of viral serological test results

A
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28
Q

What is the standard approach to HBV serological testing

A
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29
Q

HBV test results interpretation

A
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30
Q

Question

A
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31
Q

Factors that may complicate interpretation of viral serologies

A
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32
Q

More factors that may complicate the interpretation of viral serologies

A
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33
Q

Viruses for which Ab detection & Quantitation are key methods of laboratory diagnosis

13 listed

A
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34
Q

Case 3

A
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35
Q

General considerations of CSF

A
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36
Q

Describe the mechanism of replication in PCR

A
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37
Q

Agents of CNS viral infections

A
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38
Q

Viral encephalitis clue:

Temporal lobe localization

A

HSV

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39
Q

Viral encephalitis clue:

animal bite or bat exposure

A

Rabies

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40
Q

Viral encephalitis clue:

exposure to mice or hamsters

A

LCMV

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41
Q

Viral encephalitis clue:

Summer or fall onset

A
  • Arboviruses
  • Enteroviruses
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42
Q

Viral encephalitis clue:

fall or winter onset

A

LCMV

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43
Q

Viral encephalitis clue:

Rash

A
  • Enteroviruses
  • HHV-6
  • Measels
  • Rubella
  • VZV
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44
Q

Viral encephalitis clue:

Parotitis/Orchitis

A

Mumps

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45
Q

What is Parotitis?

A

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

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46
Q

What is orchitis?

A

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.

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47
Q

Viral encephalitis clue:

Concurrent or recent chicken pox or shingles

A

VZV

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48
Q

Viral encephalitis clue:

recent respiratory illness

A
  • Influenza
  • parainfluenza
  • adenovirus
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49
Q

Viral encephalitis clue:

IM-like illness

A
  • EBV
  • CMV
  • HIV
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50
Q

Viral encephalitis clue:

HIV risk factors

A
  • HIV
  • Herpesviruses
  • JC virus
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51
Q

Viral encephalitis clue:

Immunosuppression

A
  • Herpesviruses
  • JC virus
  • Measles
  • Adenovirus
52
Q

Case 4

A
53
Q

Herpesviruses that infect humans

A
54
Q

HHV-1 AKA

A

Herpes simplex virus 1

55
Q

HHV-2 AKA

A

Herpes Simplex virus 2

56
Q

HHV-3 AKA

A

Varicella-Zoster Virus

57
Q

HHV-4 AKA

A

Epstein-Barr Virus

58
Q

HHV-5 AKA

A

Cytomegalovirus

59
Q

HHV-6 AKA

A

HHV-6

60
Q

HHV-7 AKA

A

HHV-7

61
Q

HHV-8 AKA

A

Kaposi’s Sarcoma Herpesvirus

62
Q

Herpesvirus simiae; Cercopthicine HV 1 AKA

A

Herpes B virus

63
Q

Herpes simplex virus 1 sub-family

A

α

64
Q

Herpes simplex virus 2 sub-family

A

α

65
Q

Varicella-Zoster virus subfamily

A

α

66
Q

Epstein-Barr Virus sub-family

A

γ

67
Q

Cytomegalovirus sub-family

A

β

68
Q

HHV-6 Sub-family

A

β

69
Q

HHV-7 sub-family

A

β

70
Q

Kaposi’s Sarcoma Herpesvirus sub-family

A

γ

71
Q

Herpesvirus simiae; cercopithicine HV-1 or Herpes B virus sub-family

A

α

72
Q

Herpes simplex virus 1 cellular receptor

A
  • Heparan sulfate
  • Nectin 1
  • Nectin 2
  • HVEM
73
Q

Herpes simplex virus 2 cellular receptor

A

Heparan sulfate

Nectin 1

Nectin 2

HVEM

74
Q

Varicella-Zoster virus cellular receptors

A

?

75
Q

Epstein-Barr virus cellular receptors

A

Complement receptor 2 (CD21)

76
Q

Cytomegalovirus cellular receptors

A
  • Heparan sulfate
  • integrins α2β1
  • Integrins α6β1
  • Integrins αvβ3
  • PDGF-α receptor
77
Q

HHV-6 cellular receptor

A

?

78
Q

HHV-7 cellular receptor

A

?

79
Q

Kaposi’s Sarcoma Herpesvirus cellular receptors

A

Integrin α3β1

80
Q

Herpesvirus simiae; cercopithicine HV-1 cellular receptors

A

?

81
Q

Describe the method of diagnosis of herpesvirus infections

A
82
Q

Describe HSV CPE in epithelial cells

A
83
Q

Pap-stained smear from HSV Vulvar Ulceration

A
84
Q

Case 5

A
85
Q

Histology of CMV infection of Pneumocytes

A
86
Q

What are the non-histologic methods of CMV detection

A
  • Conventional Cx
  • Shell vial Cx
  • Antigenemia
  • PCR
87
Q

Conventional Cx advantages

A
  • specific
  • multiple specimen types
  • Isolates for further testing
88
Q

Conventional Cx disadvantages

A
  • Slow (usually 7-21 days)
  • requires virus viability
  • suboptimal for blood
89
Q

Shell vial Cx advantages

A
  • Rapid (24-48 hours)
  • Multiple specimen types
90
Q

Shell vial Cx disadvantages

A
  • Requires virus viability
  • interference from cytotoxicity
  • suboptimal for blood
  • Sensitivity may be lower than traditional Cx
91
Q

Antigenemia advantages

A
  • Rapid (2-4 hours)
  • Sensitive
  • Quantitative
  • Viable virus not required
  • Systemic Dz monitoring
92
Q

Antigenemia disadvantages

A

Antigen unstable with ex-vivo storage

93
Q

PCR advantages for virus detection

A
  • sensitive
  • Viable virus not required
  • Systemic Dz monitoring
  • Stable target
  • Can be made quantitative
94
Q

PCR disadvantages for virus detection

A

quantitative assay may be too sensitive for clinical utility

95
Q

CMV cytopathicity in human fibroblasts

A
  • 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
Q

Shell vial culture fluorescence antibody staining using CMV-immediate-early protein

A
97
Q

Community-acquired CMV clinical syndromes in fetus and newborn by intrauterine transmission

A

Congenital CMV infection with CNS disease, hepatitis and thrombocytopenia

98
Q

Community-acquired CMV clinical syndromes in fetus and newborn by intrapartum transmission

A

Asymptomatic infection with CNS sequelae (hearing-loss)

99
Q

Community-acquired CMV clinical syndromes in fetus and newborn by breast-milk transmission

A

Asymptomatic infection with prolonged shedding

100
Q

Community-acquired CMV clinical syndromes in children by saliva transmission

A

Asymptomatic infection

101
Q

Community-acquired CMV clinical syndromes in children by urine transmission

A

Infrequent IM-like syndrome

102
Q

Community-acquired CMV clinical syndromes in adolescents and young adults by saliva transmission

A

IM syndrome

103
Q

Community-acquired CMV clinical syndromes in adolescents and young adults by sexual transmission

A

Asymptomatic infection

104
Q

Iatrogenic CMV clinical syndromes in blood transfusion recipients by leukocyte transmission

A

IM syndrome with more severe symptoms

105
Q

Iatrogenic CMV clinical syndromes in transplant recipients by CMV in allograft transmission

A

IM syndrome

106
Q

Iatrogenic CMV clinical syndromes in transplant recipients by Blood transfusion transmission

A
  • Leukopenia and thrombocytopenia
  • Hepatitis
  • Colitis
  • Pneumonia
  • Chronic graft rejection
107
Q

Case 6

How would you identify this infection?

A
108
Q

Specific agents of viruses readily isolated in cell culture of Herpesviruses

A
  • Herpes simplex 1 and 2
  • Varicella-Zoster
  • Cytomegalovirus
109
Q

Specific agents of viruses readily isolated in cell culture of Adenovirus

A

All except enteric stains (40, 41)

110
Q

Specific agents of viruses readily isolated in cell culture of Enterovirus

A
  • Echovirus
  • Coxsackie B
  • Poliovirus
111
Q

Specific agents of viruses readily isolated in cell culture of Orthomyxoviruses

A

Influenza A and B

112
Q

Specific agents of viruses readily isolated in cell culture of Paramyxoviruses

A
  • Parainfluenza
  • Respiratory syncytial virus
  • Human metapneumovirus
  • Mumps
  • Measles
113
Q

Specific agents of viruses readily isolated in cell culture of Rhinovirus

A

All strains

114
Q

Viruses that are impractical or impossible to isolate and culture-specific agents of Hepatitis

A
  • A
  • B
  • C
  • D
  • E
  • G
115
Q

Viruses that are impractical or impossible to isolate in culture-specific agents of Gastroenteritis

A
  • Rotavirus
  • Calcivirus (eg norwalk)
  • Astrovirus
116
Q

Viruses that are impractical or impossible to isolate in culture-specific agents of Herpesviruses

A
  • EBV
  • HHV-6/7
  • KSHV
117
Q

Viruses that are impractical or impossible to isolate in culture-specific agents of Coronaviruses

A

All respiratory strains (incl. SARS)

118
Q

Viruses that are impractical or impossible to isolate in culture-specific agents of Parvovirus

A

B19

119
Q

Viruses that are impractical or impossible to isolate in culture-specific agents of Retroviruses

A
  • HTLV 1 and 2
  • HIV 1 and 2
120
Q

Viruses that are impractical or impossible to isolate in culture-specific agents of Papovaviruses

A
  • Human pailloma
  • JC polyoma
  • BK polyoma
121
Q

Viruses that are impractical or impossible to isolate in culture-specific agents of Arenaviruses

A

Lymphocytic chorionic meningitis virus

122
Q

Viruses that are impractical or impossible to isolate in culture-specific agents of Arboviruses

A
  • Many examples
  • eg West Nile
123
Q

Viruses that are impractical or impossible to isolate in culture-specific agents of Acute hemorrhagic fever viruses

A
  • Many examples
  • eg Ebola
124
Q

Describe virus isolation using cell culture tubes

A
125
Q

Shell vial virus isolation

A
126
Q

Comparing virus discovery options

A