Methods of Diagnostic Virology

Question 1

What are the different methods of diagnostic virology?

Answer 1

Direct detection
Virus Isolation Culture
Nucleic Acid-based detection
Serologic assays to detect antiviral antibodies

Question 2

A method of diagnostic virology that is:

• Not as sensitive as culture methods
• Performed in a few minutes
• Allow clinicians to make relevant decisions about therapy and hospitalization

Answer 2

Direct detection

Question 3

Individual virus particles are too small to be seen by bright-field microscopy except for the _____.

Answer 3

Poxvirus

Question 4

This type of microscopy can detect noncultivatable viruses

Answer 4

Electron microscopy

Question 5

These are noncultivatable viruses in stool filtrates that can be seen using electron microscopy.

Answer 5

Norwalk viruses

Question 6

These are characteristic visual changes in infected cells (lymphocytes) produced by many viruses.

Answer 6

Cytopathic effects (CPE)

Question 7

What is the specimen used to detect cytopathic effects?

Answer 7

Cell scrapings from infected sites

Question 8

This type of smear can detect Cowdry type A bodies (“Owl Eyes”) from herpes simplex virus (HSV) and Varicella-Zoster virus (VZV).

Answer 8

Tzanck smear

Question 9

This type of smear can reveal human papillomavirus (HPV)-associated koilocytosis-squamous cells with an enlarged nucleus surrounded by a non-staining halo.

Answer 9

Papanicolaou (Pap) smear

Question 10

Rabies is sometimes diagnosed by detecting _____ bodies, which are eosinophilic cytoplasmic inclusions in neurons.

Answer 10

Negri

Question 11

This is the gold standard against which all other methods of diagnostic virology are compared.

Answer 11

Isolating viruses

Question 12

What are the three methods used for the isolation of viruses in diagnostic virology?

Answer 12

Cell culture
Animal inoculation
Embryonated eggs

Question 13

This is the most used method for the isolation of viruses.

Answer 13

Cell culture

Question 14

This method of isolating viruses is extremely costly and is used only as a special resource and in reference laboratories

Answer 14

Animal inoculation

Question 15

This is a term used to indicate culture of cells in vitro; the cells are not organized into a tissue.

Answer 15

Cell culture

Question 16

This term is used to denote growth of tissues or an organ in any way that preserves the architecture or function of the tissue or organ.

Answer 16

Tissue culture or Organ culture

Question 17

What are the three categories of cell cultures?

Answer 17

Primary
Low passage (or finite)
Continuous

Question 18

This type of cell culture is obtained from tissue removed from an animal.

Answer 18

Primary cell culture

Question 19

What are the steps in preparing a primary cell culture?

Answer 19

The tissue is finely minced
It is treated with an enzyme such as Trypsin to disperse individual cells further
Cells are seeded onto a surface to form a monolayer, such as in a flask or tube

Question 20

Give an example of a commonly used primary cell culture.

Answer 20

Primary monkey kidney (PMK) cells

Question 21

To maintain cell viability, they must periodically be removed from the surface, diluted, and placed into a new container. This process is referred to as _____.

Answer 21

Splitting or Passaging

Question 22

Enumerate some primary cell cultures that have the same karyotype and chromosome number as the original tissue.

Answer 22

Human embryonic kidney HEK
Rabbit embryonic kidney REK
Primary monkey kidney PMK
Rhesus monkey kidney RMK
Cynomolgus monkey kidney CMK
African green monkey kidney AGMK

Question 23

It is a type of cell culture also known as the diploid cell line.

Answer 23

Low Passage (Finite) Cell culture

Question 24

Low Passage (Finite) Cell cultures can divide, but passage is limited to ___ generations.

Answer 24

50

Question 25

Finite cell lines and primary cell lines are (diploid/haploid), meaning they contain two copies of each chromosome.

Answer 25

Diploid

Question 26

Give an example of a standard finite cell culture used in diagnostic virology.

Answer 26

Human neonatal lung (HNL)

Question 27

This is a subcultivated primary cell culture wherein >/= 75% of cells have the same karyotype as the normal cells

Answer 27

Cell line

Question 28

These are cell cultures that are capable of infinite passage.

Answer 28

Continuous Cell line/culture

Question 29

This is the cell culture also known as the Heteroploid cell line.

Answer 29

Continuous Cell line/culture

Question 30

Continuous Cell line/culture are _____, meaning they have an abnormal and variable number of chromosomes that is not a multiple of the normal haploid cell.

Answer 30

Heteroploid

Question 31

These are cell lines wherein <75% of cells have the same karyotype as the normal cells

Answer 31

Heteroploid or immortal cell lines

Question 32

Enumerate some examples of continuous cell cultures.

Answer 32

``` Human cervical carcinoma HeLa Human laryngeal carcinoma Hep-2 Nasopharyngeal carcinoma KB Human lung carcinoma A-549 African green monkey kidney Vero ```

Question 33

What are the different cytopathic effects on cell culture?

Answer 33

1. Rounding 2. Clumping 3. Vacuolation 4. Granulation 5. Giant multinucleated cell 6. Syncytial formation 7. Cell destruction 8. Cell lysis

Question 34

This is a virus that grows rapidly on many different cell lines and frequently produces CPE within 24 hours. Produces a focal CPE and plaques, or clusters of infected cells.

Answer 34

Human simplex virus (HSV)

Question 35

The combination of rapid growth , plaque formation, and growth on many different cell types such as MRC-5, human frobroblasts, Vero, HEp-2, mink lung, rabbit kidney cells, and PMK, is presumptive evidence for the identification of what virus?

Answer 35

Human simplex virus (HSV)

Question 36

What virus would have these characteristics: (- growth) (PMK) Primary monkey kidney (+++) (HDF) Human diploid fibroblasts (+++) (HEp2) Human laryngeal carcinoma cell line (+++) (RK) Rabbit kidney (+++) (A549) Human lung carcinoma cell line CPE: large rounded cells

Answer 36

Human simplex virus (HSV)

Question 37

What virus would have these characteristics: (- growth) (PMK) Primary monkey kidney (+++) (HDF) Human diploid fibroblasts (- growth) (HEp2) Human laryngeal carcinoma cell line (- growth) (RK) Rabbit kidney (- growth) (A549) Human lung carcinoma cell line CPE: large rounded cells

Answer 37

Cytomegalovirus (CMV)

Question 38

What virus would have these characteristics: (- growth) (PMK) Primary monkey kidney (+++) (HDF) Human diploid fibroblasts (- growth) (HEp2) Human laryngeal carcinoma cell line (- growth) (RK) Rabbit kidney (-/+) (A549) Human lung carcinoma cell line CPE: foci or rounded cells; possible syncytia

Answer 38

Varicella-Zoster virus (VZV)

Question 39

What virus would have these characteristics: (+) (PMK) Primary monkey kidney (+) (HDF) Human diploid fibroblasts (++) (HEp2) Human laryngeal carcinoma cell line (- growth) (RK) Rabbit kidney (+) (A549) Human lung carcinoma cell line CPE: Refractile, round cells in clusters

Answer 39

Enterovirus

Question 40

What virus would have these characteristics: (+) (PMK) Primary monkey kidney (++) (HDF) Human diploid fibroblasts (+++) (HEp2) Human laryngeal carcinoma cell line (- growth) (RK) Rabbit kidney (++) (A549) Human lung carcinoma cell line CPE: Large, round cells in clusters

Answer 40

Adenovirus

Question 41

What virus would have these characteristics: (-/+) (PMK) Primary monkey kidney (+) (HDF) Human diploid fibroblasts (+++) (HEp2) Human laryngeal carcinoma cell line (- growth) (RK) Rabbit kidney (++) (A549) Human lung carcinoma cell line CPE: Syncytia

Answer 41

Respiratory syncytial virus

Question 42

What virus would have these characteristics: (+++) (PMK) Primary monkey kidney (-/+) (HDF) Human diploid fibroblasts (- growth) (HEp2) Human laryngeal carcinoma cell line (- growth) (RK) Rabbit kidney (- growth) (A549) Human lung carcinoma cell line CPE: Variable (none to granular appearance)

Answer 42

Influenza/parainfluenza

Question 43

This virus shows rapid growth in HDF, but no growth in OMK, HEp2, RK and A549. Its CPE is the appearance of large, rounded cells

Answer 43

Cytomegalovirus (CMV)

Question 44

These are giant multinucleated cells formed from cell fusion as a result of virus infection

Answer 44

Syncytia

Question 45

This is a simple method that more rapidly identifies viruses than does the traditional cell culture cell method.

Answer 45

Shell vial culture technique

Question 46

This is a small, round, flat-bottom tube, generally with a screw cap.

Answer 46

Shell vial

Question 47

In this type of cell culture, cells are grown on a round cover slip in a shell vial.

Answer 47

Centrifugation-Enhanced Shell vial culture

Question 48

The shell vial is inoculated with the clinical sample and then centrifuged to promote _____.

Answer 48

Viral absorption

Question 49

(T/F) Serologic assays are retrospective studies

Answer 49

T

Question 50

What are the disadvantages of serologic assays?

Answer 50

1. Measures host response rather than detection of virus 2. Antibody producing capabilities of human hosts vary widely 3. Antibody level doses are not necessarily correlated with the acuteness or activity level of the infection

Question 51

The presence of what immunoglobulin indicates an acute infection?

Answer 51

IgM

Question 52

What are the indications of serologic testing?

Answer 52

1. Diagnosis of infections with non-culturable agents 2. Determination of immune status (rubella, measles, VZV, HAV, HBV) 3. Monitoring of patients who have immunosuppresion 4. Epidemiologic or prevalance status

Question 53

What are the types of viruses based on nucleic acid?

Answer 53

Double-stranded DNA viruses (dsDNA) Single-stranded DNA viruses (ssDNA) Single-stranded RNA viruses (ssRNA) Double-stranded RNA viruses (dsDNA)

Question 54

What are the general types of the clinically significant viruses?

Answer 54

``` Double-stranded DNA viruses (dsDNA) Single-stranded DNA viruses (ssDNA) Single-stranded RNA viruses (ssRNA) Double-stranded RNA viruses (dsDNA) Hepatitis virus ```

Question 55

What are the two types of dsDNA?

Answer 55

Enveloped | Naked

Question 56

What are the two types of enveloped dsDNA?

Answer 56

Icosahedral | Complex

Question 57

Give a specific type of an icosahedral, enveloped dsDNA?

Answer 57

Herpesviridae (Simplex virus, varicella virus)

Question 58

Give a specific type of a complex, enveloped dsDNA?

Answer 58

Poxviridae (Orthopoxvirus [Variola, Vaccinia])

Question 59

Give specific types of icosahedral, naked dsDNA

Answer 59

Papillomaviridae (Papillomavirus) | Adenoviridae (Mastadenovirus)