Laboratory: Diagnostic Virology Flashcards
Purposes of Viral Laboratory Studies
Confirm the diagnosis by identifying the viral agent of infection
Define the disease process
Monitor the disease epidemiologically
Educate physicians and patients
Commonly used swab
Dacron or rayon
Inhibit the replication of some viruses & interfere NAAT
Calcium alginate swabs
At what temperature does VTM form ice crystals?
-20 degrees Celsius
Ideal temperature of VTM when delayed for 4-7 days?
-70 degrees Celsius
Antibacterial and antifungal agents are added to
transport systems to?
Inhibit contaminating microorganisms
Samples that should be collected without viral transport
media include:
Blood, bone marrow, CSF, amniotic fluid, urine, pericardial fluid, and pleural fluid
In collecting BAL, saline is injected in?
Subsegmental bronchus
In collecting BW, saline is injected in?
Segmental bronchus
In collecting buccal swab, _ gland is massaged for _ seconds and swab is performed at the buccal mucosa near _
Parotid
30
Stensen’s duct
1st swab in cervical swab is for removing _ and is discarded
Cervical mucus/exudates
2nd swab in cervical swab is used to collect _
Epithelial cells
CSF is collected at least _ mL into a sterile container
2 mL
Swab used for conjunctiva is moistened with?
Sterile physiologic saline
In collecting lesions swab, you should select _ lesion with _ fluid and clean exterior with _
Non-crusted
Clear
Sterile saline
Fluid from lesions can be aspirated with _
26-30 gauge tuberculin needle
Number of virions shed from the lesion decreases
dramatically each day after the lesion manifests. True or False?
True
In NP swab, a swab with _ is inserted into _ nasopharynx
Flexible metal shaft
Posterior
In rectal swab, use of _ is not encouraged
Lubricant
What type of swab is preferred in stool and rectal swab?
Culturette swab
Diagnostic method with excellent sensitivity and specificity
Molecular diagnostics
Diagnostic method with maximum specificity
Culture
Diagnostic method characterized by its speed of diagnosis
Antigen detection
Diagnostic method that assesses immunity
Serology
Not sensitive as culture methods; offer quick results to allow for rapid therapy
Direct Viral Detection
What type of microscope is used in DVD?
Electron microscope
In immunologic Detection of Viral Antigen, what assay is used?
Enzyme immunoassay
Rarely used in clinical laboratories; suitable for large teaching or research institutions
Electron Microscopy
Used to visualize inclusion bodies; observes cytopathic effect (CPE) in cell cultures
Bright field Light Microscopy
Dense aggregates of stainable substances of viruses, usually proteins; produced due to developmental / maturation process of virus or in some viruses seen only after viral multiplication
Inclusion Bodies
Intracytoplasmic inclusion bodies in Rabies
Negri bodies
Intracytoplasmic inclusion bodies in Smallpox
Guarnieri bodies
Intracytoplasmic inclusion bodies in Fowl pox
Bollinger bodies
Intracytoplasmic inclusion bodies in Mollascum contagiosum
Henderson-Peterson bodies
Guarnieri bodies are also known as?
Paschen bodies
Herpes simplex and VZV is classified as what type?
Cowdry Type A
Infection with poliovirus is classified as what type?
Cowdry Type B
Herpes simplex and VZV has what intranuclear inclusion?
Lipschutz inclusions
Yellow fever has what intranuclear inclusion?
Torres Bodies
Measles has what kind of inclusion?
Warthin-Finkeldey bodies
CMV has what kind of appearance?
Owl’s eye
Cells from a patient are fixed to a microscope slide; fluorescence-labeled antibodies are added
Immunofluorescence Microscopy (DFA Assays)
Positive reaction in DFA assays
Labeled antibody will bind and fluoresce
These assays enable the diagnosis of some viruses within 10-30 minutes
Rapid Antigen Assays
Obtained from animal tissue
Primary Cell Cultures
Cell lines can divide; diploid cells
Finite Cell Cultures
Capable of infinite passage; heteroploid
Continuous Cell Cultures
Cell culture with greater sensitivity
Mixed Cells Culture
PMK cells means?
Primary Monkey Kidney cells
PMK cells are under what type of cell culture?
Primary Cell Cultures
Human neonatal lung cells are under what type of cell culture?
Finite Cell Cultures
Hep2, A549 and Vero are under what type of cell culture?
Continuous Cell Cultures
What virus reacts positively with rabbit kidney?
Herpes simplex virus
All viruses have positive reaction with what cell culture?
Human diploid fibroblasts (HDF)
Herpes simplex virus only reacts negatively with?
Primary monkey kidney cells
CMV only reacts positively with?
HDF
Enterovirus and Adenovirus only reacts negatively with?
Rabbit kidney
CPE of Herpes simplex virus
Large rounded cells
CPE of CMV
Large rounded cells
CPE of VZV
Foci or rounded cells; possible synctia
CPE of Enterovirus
Refractile; round cells in clusters
CPE of Adenovirus
Large rounded cells in clusters
CPE of Respiratory synctial virus
Synctia
CPE of Influenza, parafluenza
Variable - none to to granular appearance
Most commonly used in virus cultivation
Rabbit
Guinea pig
Mouse
Rat
Certain _ viruses require _ for isolation of the virus
Coxsackie A
Suckling mice
Rarely used for virus cultivation
Embryonated eggs
Modified cell culture; rapid detection of viruses in vitro
Centrifugation-Enhanced Shell Vial Culture
Morphological change produced by the virus in the cell line
Cytopathic Effect (CPE)
Growth of the first virus inhibit by the second virus
Viral Interference
DFA assays uses _ counterstain that can be seen as _ fluorescence in the background
Evans Blue
Red
Green fluorescence indicated what in DFA assays?
Antigen is detected
Utilizes PCR or nucleic acid probes
Viral Genes Detection
Detects circulating antibodies to viruses after exposure.
Serologic Assays
Serologic assays directly detects the virus rather than measure the host response. True or False?
False, serological assays measure the host response rather than detecting the virus
