Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Parvoviridae > Flashcards

Parvoviridae Flashcards

1
Q

Simplest DNA viruses

A

Parvoviruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Because of small coding capacity of their genome, viral replication of Parvovirus is dependent on functions supplied by?

A

Replicating host cells and co-infecting helper cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Parvovirus B19 has a tropism for which cells?

A

Erythroid Progenitor Cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Parvovirus B19 causes which common childhood exanthema?

A

Erythema infectiosum (fifth disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Parvovirus B19 disease in normal adults?

A

Polyarthralgia-arthritis Syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Parvovirus B19 causes what disorder in patients with haemolytic disorders?

A

Aplastic crisis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Parvovirus B19 in immunocompromised individuals?

A

Chronic Anemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Parvovirus B19 pre-birth

A

Fetal Death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A newly detected parvovirus found in respiratory and stool specimens of children with ARDS, but role still uinproven.

A

Human Bocavirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Parvoviruses: Virion properties (shape, diameter and number of capsomeres)

A

Icosahedral
18 - 26 nm in diameter
32 capsomeres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Composition of Parvovirus

A

20% DNA

80% Protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Proteins of Parvovirus

A

1 major VP2, which is 90% of virion protein

1 minor VP1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Which encodes the virion proteins of parvoviruses?

A

Encoded by an overlapping, in-frame DNA sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

PV: VP2 is identical in sequence to which portion of VP1?

A

Carboxy Portion of VP1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Parvoviruses: Encapsulated or nonencapsulated?

A

Nonencapsulated, no envelope, nada, nil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Replication of parvoviruses

A

Dependent on functions of dividing cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

True or false. There are both autonomous-replicating and defective parvoviruses.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Molecular weight of parvoviruses.

A

5.5 - 6.2 x 10^6

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Buoyant density of parvoviruses

A

1.39 - 1.42 g/cm^3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Virions of parvoviruses are extremely resistant to inactivation. They are stable at pH of?

A

pH 3 and 9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Virions of parvoviruses can withstand heating at what temperature?

A

Temp of 56C for 60 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Parvoviruses can be inactivated by:

A

Formalin
Beta-propiolactone
Oxidizing agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Has 5596 nucleotides.

Usually encapsidates primarily DNA strands complementary to viral mRNA.

A

Autonomous virus (B19)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Has 4680 bases

Encapsidates DNA strands of both polarities with equal frequency into separate virions.

A

Defective Virus (AAV-2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

2 subfamilies of Parvovirus

A
  1. Densovirinae

2. Parvovirinae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Subfamily of parvoviruses which infects insects

A

Densovirinae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Subfamily of parvoviruses which infects vertebrates

A

Parvovirinae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Human Parvovirus B19 (Type 1) is the most common member of which genus?

A

Erythrovirus genus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Give the 2 new human genotypes identified recently that differ about 10% in nucleotide sequence from B19.

A

Strains K71- Type 2

Strains V9- Type 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Human bocavirus is under what genus?

A

Bocavirus genus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Members of Parvovirus genus that cause serious veterinary diseases

A

Feline panleukopenia virus

Canine parvovirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Parvovirus genus that contains members that are DEFECTIVE and DEPENDENT ON HELPER VIRUS for replication.

A

Genus Dependovirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Genus Dependovirus depends on which helper viruses?

A

Adenovirus

Herpes virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

True or False. Human “adeno-associated virus” have not been linked with any disease.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Human B19 parvovirus is difficult to culture. Which cells are permissive for B19 infection?

A

Primary Erythrooid Progenitors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Cellular receptor for Parvovirus B19 is?

A

Blood group P antigen (globoside)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

P antigen is expressed on which 7 tissues?

A 
Mature erythrocytes
Erythroid progenitors
Megakaryocytes
Endothelial cells
Placenta
Fetal liver
Fetal heart
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Because P antigen is expressed on few tissues only, this explains its ____ tropism.

A

narrow tissue tropism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Parvovirus DNA replication occurs in what part of the cell?

A

Nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Effect of Parvoviruses on resting cells?

A

None. Parvoviruses do not have the ability to stimulate resting cells to initiate DNA synthesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are involved for Parvovirus replication?

A
  • 1 or more DNA polymerases

- 2 capsid proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

These are used as primers to initiate DNA synthesis

A

Terminal sequences on the linear parvovirus DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Parvovirus replication results in?

A

Cell death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

This essential nonstructural protein of Parvovirus is required for viral replication and modulating host cell genes.

A

Non-structural viral protein (NS1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Narrate replication cycle of Parvovirus

A
  1. Parvovirus binds to erythrocyte P Ag and enters the cell
  2. Translocation of viral DNA to the host nucleus
  3. Transcription of non-structural RNA
  4. Transcription of capsid protein RNA
  5. Protein translation
  6. Capsid assembly
  7. Non-structural protein action on viral DNA
  8. Capsid translocation to nucleus
  9. DNA replication
  10. Insertion of DNA into intact capsids
  11. Virus released
  12. Cell lysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Give the clinical feature of the PV B19 human infection: Erythema infectiosum in children

A

Cutaneous rash

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Give the clinical feature of the PV B19 human infection: Erythema infectiosum in adults

A

Arthralgia-arthritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Give the clinical feature of the PV B19 human infection: Transient Aplastic Crisis

A

Severe Acute Anemia due to hemolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Give the clinical feature of the PV B19 human infection: Pure Red Cell Aplasia in the Immunodeficient

A

Chronic Anemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Give the clinical feature of the PV B19 human infection: Fetus with Hydrops Fetalis

A

Fatal Anemia

51
Q

The 1st phase of illness with flu-like symptoms in PV B19 Human Infection coincides with?

A

Viremia on days 6 - 12, manifested as myalgia, fever and malaise

52
Q

The 2nd phase of illness with flu-like symptoms in PV B19 Human Infection coincides with?

A

Appearance of rashes and arthralgia-arthritis on day 18

53
Q

What are the 3 major sites of PV B19 viral replication?

A

Adult marrow
Blood cells
Fetal liver

54
Q

PV B19 replication leads to cell death that interrupts?

A

Red cell production

55
Q

Antibodies made following B19 infections.

A

IgM and IgG

56
Q

Persistent parvovirus infections occuring in immunodeficient patients who fail to make virus-neutralizing antibodies result in?

A

Anemia

57
Q

Persistence of low levels of B19 DNA, and to a lesser extent virus type 2 DNA, has also been detected in which 5 tissues of immunocompetent volunteers.

A 
blood
skin
tonsil
liver
synovial tissues
58
Q

Modes of transmission of parvoviruses?

A
  1. Respiratory route
  2. Parenterally by blood transfusion and infected blood products (clotting and Ig concentrates)
  3. Vertically from mother to fetus
59
Q

PVB19 are found in which specimens?

A

Blood and respiratory secretions

60
Q

PVB19 can be isolated from urine and feces. True or False?

A

False

61
Q

Prevalence of antibodies to B19 is higher among _____ than general population

A

Haemophiliacs

62
Q

Why do some clotting factor concentrates end up contaminated?

A

B19 is resistant to harsh treatments that inactivate enveloped viruses.

63
Q

MOT of Human Bocavirus

A

Respiratory route

64
Q

Several pathogenic parvoviruses of animals replicate in intestinal mucosal cells and cause?

A

Enteritis

65
Q

Common manifestation of human parvovirus B19.

A

Erythema infectiosum

66
Q

Erythema infectiosum is most common in which child group?

A

Early school age

Children with acute wheezing

67
Q

Characteristic rash in erythema infectiosum

A

Slapped Cheek Appearance

68
Q

A prominent feature of erythema infectiosum in adults

A

Involvement of the joints in the hands and knees

69
Q

Symptoms of erythema infectiousm mimic?

A

Rheumatoid arthritis

70
Q

Incubation period in erythema infectiosum?

A

IP of 1 - 2 weeks, may extend up to 3 weeks

71
Q

Viremia in erythema infectiosum occurs ____ week after infection and persists for ______

A

Viremia occursd 1 week after infection and persists for 5 days

72
Q

PVB19 in erythema infectiosum is present in which specimens?

A

Nasal washes

Gargle specimens

73
Q

Most probable site of viral shedding in erythema infectiosum

A

Pharynx

74
Q

First phase of erythema infectiosum occurs at ___ (time)

A

End of the 1st week

75
Q

Manifestations in the 1st phase of erythema infectiosum

A 
Flu-like symptoms:
Fever
Malaise
Myalgia
Chills
Itching
76
Q

First episode of erythema infectiosum coincides with?

A
  1. Viremia and reticulocytopenia

2. Detection of circulating IgM-parvovirus immune complexes

77
Q

2nd phase of erythema infectiosum begins after IP of?

A

17 days

78
Q

2nd phase of erythema infectiosum is manifested as?

A
  1. Erythematous facial rash
  2. Lace-like rash on limbs and trunk
  3. Joint symptoms, esp. in adults
79
Q

2nd phase of erythema infectiosum is short-lived, with rash fading after?

A

After 2 - 4 days, although joint symptoms may persist longer

80
Q

Antibody that appears 1 day post infection in erythema infectiosum

A

Specific IgG antibodies

81
Q

Parvovirus B19 transient aplastic crisis may complicate cases of?

A

Chronic Hemolytic Anemia, e.g. Sickle Cell Disease, Thalassemia, Acquired Hemolytic Anemia in adults

82
Q

Transient aplastic crisis in PVB19 infection may also occur after which operation?

A

Post bone marrow transplant

83
Q

Abrupt cessation of RBC synthesis in PVB19 infection is reflected by:

A
  • Absence of erythroid precursors in marrow

- Accompanied by rapid worsening of anemia

84
Q

Temporary arrest in production of RBCs become apparent only in patients with chronic haemolytic anemia because of?

A

short lifespan of their erythrocytes

85
Q

True or False. 7-day interruption in erythropoiesis would not be expected to cause detectable anemia in normal person.

A

True

86
Q

Few anemia patients with PVB19 infection have this sign

A

rash

87
Q

Symptoms of Transient Aplastic Crisis in PVB19 infection occur during which phase?

A

Viremic Phase

88
Q

B19 may establish persistent infections and cause chronic suppression of bone marrow and chronic anemia in immunocompromised patients which is identified as?

A

Pure Red Cell Aplasia (severe anemia)

89
Q

Immunideficeint patients with pure red cell aplasia are dependent on?

A

Blood transfusions

90
Q

PVB19 Pure Red Cell Aplasia has been observed in which populations?

A

Those with congenital immunodeficiency, malignancies, AIDS, and organ transplants

91
Q

Maternal infection with B19 may pose a serious risk to the fetus, resulting in ______ and ____due to severe anemia

A

HYDROPS FETALIS AND FETAL DEATH

92
Q

True or False. Fetal loss occurs in less than 10% of primary maternal infections. Therefore, overall risk during pregnancy is low.

A

True

93
Q

Fetal death in PVB19 Hydrops Fetalis occurs most commonly when?

A

before the 20th week of pregnancy

94
Q

True or False. There is frequent intrauterine transmission of human parvovirus (with vertical transmission rates of 30% or higher)

A

True

95
Q

Maternal-fetal transmission of pVB19 may occur most commonly in pregnant women with

A

High plasma viral loads

96
Q

Most sensitive assay for PVB19 detection of viral DNA

A

PCR

97
Q

During acute infections, viral loads in the blood can reach approximately ___ seen in PCR

A

10^11 genome copies/ml

98
Q

PCR assays based on B19 may miss non-B19 strains due to?

A

Sequence differences

99
Q

The only assay available for human bocavirus

A

PCR

100
Q

Serologic assays of PVB19 are based on

A

recombinant parvovirus B19 antigens produced in vitro using bacterial or baculovirus expression systems to measure antibodies

101
Q

Appears to be optimal as antigen for antibody detection in serologic assays in PVB19

A

VP2 virus-like particles

102
Q

Detection of ____ is indicative of recent infection with B19; it is present for ____ mos. after infection

A

B19 IgM antibody present after 2 - 3 months

103
Q

B19 ___ antibody against conformational epitopes on VP1 and VP2 persists for years, although antibody responses against linear epitopes decline within mos. Of postinfection

A

IgG

104
Q

Since antibodies may not be found in chronic B19 infections in immunodeficient patients, how can PVB19 infection be diagnosed?

A

By detection of viral DNA

105
Q

Can identify high-titered B19 virus in clinical samples

A

Antigen detection assays

106
Q

Has been used to detect B19 antigens in fetal tissues and in bone marrow

A

IHC Antigen detection assays

107
Q

True or False. Viral isolation is used to detect PVB19 infection.

A

False.

108
Q

Antibodies against PVB19 most often develop between ages?

A

5 and 19 years

109
Q

Main path of PVB19 transmission:

A

transfer among siblings and children in schools and daycare centers

110
Q

True or False. Transmission of B19 from patients with aplastic crisis to hospital staff has been documented

A

True

111
Q

True or False. Patients with aplastic crisis are likely to be infectious during the course of their illness.

A

True

112
Q

True or False. Patients with fifth disease are probably no longer infectious by the time of onset of rash.

A

True

113
Q

In PVB19 infection, Fifth disease and transient aplastic crisis are treated

A

Symptomatically

114
Q

These can sometimes ameliorate persistent B19 infections in immunocompromised patients and in those with anemia.

A

Commercial immunoglobulin preparations containing neutralizing antibodies to human parvovirus

115
Q

Treatment for bocavirus infections.

A

None

116
Q

Vaccine for Human PV infection

A

None

117
Q

Antiviral drug therapy for PVB19

A

None

118
Q

Practices helpful in the prevention and control of PVB19

A

hand washing and not sharing drinks

119
Q

should be followed among health care workers from patients with aplastic crisis and from immunodeficient patients with chronic B19 infection

A

STANDARD infection control practices

  • Hand Hygiene
  • PPE
  • Respiratory hygiene and cough etiquette
120
Q

DNA genome of Parvovirus

A

single stranded

121
Q

Best describes replication of human infections by Parvovirus B19

A

Uses blood group antigen P as cellular receptor

122
Q

Available as treatment or preventive for Parvovirus B19 infection

A

Commercial immunoglobulin

123
Q 
Which is not a shared property of human erythroviruses and bocaviruses?
A. Small, nonevnveloped virus particles
B. Difficult to culture
C. Cause anemia
D. Global distribution
E. No vaccine exists
A

C. Cause anemia

Microbiology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions