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Flashcards in Virology Deck (42)
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1

causes infectious mononucleosis

Epstein-Barr virus causes infectious mononucleosis, which is associated with atypical (reactive) lymphocytosis. Because of the difficulty in culturing Epstein-Barr virus, and readily available heterophile antibody test and serology, it is rarely necessary to culture this virus in routine clinical

2

Most common cause of genital ulcers

Genital herpes (HSV-1, HSV-2)

3

Most common viral STD Condyloma accuminatum/a = genital wart(s) Can be on cervix, perianal, penile, inside urethra, on thigh, on tongue

HPV Mostly due to types 6 & 11 (most warts), also 16, 18, & 32

4

Transport temperature for viral culture

4o if less than a day

store at -80 if transport is delayed >24 hrs

5

Packaging for viral samples

TRIPLE PACKED

  1. Leak-proof plastic bag with absorbent material
  2. Crush-proof container with coolant
  3. Cardboard box labeled with a Type B diagnostic specimen label

Paperwork packaged separately in lead-proof bag with at least two patient identifiers

6

When is transport media not required?

If only PCR is to be done

Also body fluids (especially CSF) should not be diluted

7

When is the best time for a urine specimen?

First morning void has highest titers

8

Collect bone marrow in what kind of tube/

EDTA

9

What tube for whole blood viral culture

Purple top vacutainer

Plasma samples collected in a green top tube are NOT acceptible for PCR

10

What are the three main types of tissue culture cell lines used for examining cytopathic effects (CPE)?

  1. Monkey Kidney- MK; primary cell line
  2. Human HeLa Line- HL; continuous cell line
  3. Human diploid fibroblasts- HDF; semi continuous cell line good for 20-25 passages

11

What do MK cells look like?

Hepatocytes from undergrad cell culture

12

What do healthy HL cells look like?

Clustery cobblestones

13

What do healthy HDF cells look like?

Swirly fingerprints.

14

Diagnostic CPE of HSV

Rapid infection of all cell lines

HDF appearing as round balloon cells resulting in total monolayer destruction

15

Diagnostic CPE of cytomegalovirus (CMV)

Grows only in diploid fibroblasts, albeit slowly

Generates boat-like patches of rounded or swolen cells

16

Diagnostic CPE of Varicella Zoster (VZV)

Grows only in HDF, albeit slowly

CPE starts as small individual patches of rounding and as virus growth proceeds, the CPE radiates out from the initial patch forming "funnel like" shapes which cover much larger portions of the cell sheet than is seen with CMV.

17

Diagnostic CPE of coxackie B virus

All six serotypes grow well in MK and HL cells but little if any growth is seen in HDF cells. The CPE is a small uniform rounding which rapidly progresses to total monolayer destruction.

18

Diagnostic CPE of Echovirus

CPE is usually best in HDF, with MK slightly less positive. No growth is seen in the HL cell line.

CPE varies from uniform small rounding in MK to a stringy appearance then cell death in HDF.

19

Dianostic CPE of Polivirus

 

The polioviruses generally grow very rapidly in all three major cell lines (MK, continuous, and HDF) and cause a uniform small rounding with rapid degeneration of the entire monolayer. The CPE looks similar to both Coxsackie B and Echoviruses.

20

Diagnostic CPE in Adenovirus

Lacy appearance in HL

21

Diagnosis of Influenza by culture

Generally no CPE

HOWEVER, hemadsorbtion to hemagglutinin sites is key in MK

22

Explain why hemadsorption is used for influenza diagnosis

Hemagglutinin is expressed on the host surface during viral replication, so the addition of RBCs to culture will result in RBC clumping

 

HAd is performed at 4oC to inhibit neuaminidase activity

23

Diagnostic CPE of Respiratory Syncytial Virus (RSV)

RSV causes syncytia (fused multi-nuclear cells) primarily in the HL cells. HDF cells may also be affected but the CPE usually appears later and appears as minor patches of cell disintegration along monolayer borders.

24

Diagnostic CPE of Rhinovirus

Usually grows best at 33° C (lower than the normal 35-37° C range) and CPE is highly retractile rounding occurring only in HDF. The involved cells appear in patches with most of the monolayer looking normal.

25

Outline steps for using fluorescent antibodies to diagnose a viral infection in a patient specimen

  1. Spin down sample
    • Supernatant used to inoculate culture
    • Pellet resuspended in PBS
  2. Drip cell suspension onto slides and air dry
  3. Fix in acetone
  4. Stain w. 1o antibody, wash, 2o antibody
  5. Examine for green fluorescence in 490-495 nm

26

FA pattern of adenovirus

Apple-green fluorescence through the entire cells. Bright fluorescence with speckling throughout the entire cell or cytoplasmic staining.

27

FA pattern for parainfluenza

Stippling and cytoplasmic staining with cellular rimming.

28

FA pattern for RSV

A bright apple-green fluorescence through the entire cell; may be speckled or solid through entire cell or capping of cells may be observed.

29

FA pattern for influenza

Bright whole cell staining and nuclear staining.

30

FA pattern for Human Metapneumovirus

A bright apple-green fluorescence through the entire cell;

may be speckled or solid through entire cell