SPECIMEN COLLECTION AND CULTIVATION OF VIRUSES Flashcards by Queenie Mae

Specimen collection depends on the ____, ____
In the requisition, the ____ and ____ should be included.
Must be collected as early as possible after the onset of symptomatic disease
____ -interfere with nucleic acid based tests, recovery of some enveloped viruses, and fluorescent-antibody test

SPECIMEN COLLECTION FOR VIROLOGY
- specific disease syndrome, viral agents
suspected
- specimen type
- suspected virus
- Calcium alginate swabs

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SUCCESSFUL LABORATORY INVESTIGATIONS

✓Collection of adequate and appropriate specimens
✓Sufficient documentation
✓Biosafety and decontamination
✓Correct packaging
✓Rapid transport
✓Choice of a laboratory that can accurately perform the tests
✓Timely communication of results

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Specialized medium used to transport and store viral samples

VIRAL TRANSPORT MEDIUM (VTM)

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Buffering Agents

Phosphate-Buffered saline: pH stability
and osmotic balance
▪Hanks’ balanced salt solution (HBSS):
mixture of salts and nutrients

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Stabilizers

Glycerol: preservation of viral particles
▪Protein Stabilizers: bovine serum albumin
to stabilize the viral particles

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Antimicrobial Agents

Antibiotics: penicillin, streptomycin,
gentamicin
▪Antifungal agents: amphotericin B

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Throat swabs
1
2
3

Enteroviruses , Adenoviruses, HSV

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Nasopharyngeal swab or aspirate
1
2
3

RSV , Influenza, Parainfluenza

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Nasal Specimen

Rhinovirus

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-____ are superior to swabs
-Swabs should be made of __,___,___,__
-Often are contaminated with bacteria.
> Contaminants may be removed by concentrating the sample through
___

THROAT, NASOPHARYNGEAL SWAB OR ASPIRATE
- aspirate
-polyester, Dacron, or rayon with plastic oraluminum shafts
- centrifugation

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Hold tongue away with tongue depressor
Locate areas of inflammation and
exudate in ____, tonsillar region of throat behind uvula
Avoid swabbing ___; do not touch tongue
Rub area back and forth with cotton or ___ swab

THROAT SWAB : POSTERIOR PHARYNGEAL SWAB
- posterior pharynx
- soft palate
- Dacron

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1 Tilt head backwards
2 Insert _____ into nostril and back
to nasopharynx
3 Leave in place a few seconds
4 Withdraw slowly; rotating motion

NASOPHARYNGEAL SWAB
- flexible fine-shafted polyester swab

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Tilt head slightly backward
Instill ___of VTM /sterile normal
saline into one nostril
Use ____
Insert ___ in nostril and
aspirate the secretion gently by
suction in each nostril

NASOPHARYNGEAL ASPIRATE
- 1-1.5 ml
-aspiration trap
- silicon catheter

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Specimen for detecting viruses that infect the lower respiratory tract( ___ and___)
Should be centrifuged to remove contaminating materials
>Not necessary if sample are for ____ and ____

BRONCHIAL AND BRONCHOALVEOLAR WASHES
- (Influenza and Adenoviruses)
- antigen
- nucleic acid testing

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RECTAL SWABS AND STOOL is Used to detect __,__,___

Rotavirus, enteric adenoviruses (serotypes 40 and 41), and enteroviruses.

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preferable for rotavirus and enteric adenovirus testing.

Stool

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___ - acceptable for detecting enteroviruses in patients suspected of having an enteroviral disease, such as ___

Rectal swabs
- aseptic meningitis

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Due to bacterial contamination in ____, centrifugation, filtration or both are
necessary for cell cultures for the recovery of viral agents
Storage: ____

stool
- 4°C or -15°C (Ag detection and PCR)

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Urine is for detection of __,__,__,__,__,__
Improved recovery: at least ___ from clean catch first morning urine
Interference of urine __ and ___ may affect viral replication
>Urine is centrifuged or filtered to remove contaminants and neutralizing pH with____

CMV, Mumps, Rubella and Measles Virus,
Polyomavirus and Adenovirus
10mL
pH and bacteria
7.5% solution of sodium bicarbonate

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Detection of HSV or VZV may require a ___ if PCR testing is not available
> are prepared by carefully unroofing the
vesicle.

Tzanck smear

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___, ___,____ , and in rare cases ___ or ___ can be detected in vesicular lesions of the skin and mucous membranes.
>Once the vesicle has ____ , detection of the virus is difficult

Enteroviruses, HSV, VZV
CMV or pox viruses
ulcerated or crusted

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STERILE BODY FLUIDS OTHER THAN BLOOD
-may contain ___, __,___,___,____
- Collected aseptically by the physician and sent to the laboratory forprocessing
-Must not be diluted with VTM-causes___
- Specimens contaminated with blood may inhibit viral cultivation due to presence of ___

CSF and pericardial and pleural fluids, Amniotic Fluid
enteroviruses, HSV, VZV, influenza viruses, or CMV
false negative results
antibodies

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Amniotic Fluid
1
2
3
.Delay in processing: Storage at refrigerated temp for ___ or ___ if longer

congenital CMV, VZV and parvovirus B19
- 48hrs or -70°C

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Viral culture of blood is used primarily to detect __; however, __,__,__,__ occasionally may be encountered

CMV
- HSV, VZV, enteroviruses and adenovirus

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___ of anticoagulated blood collected in a whole blood tube is needed - __,__,___ anticoagulated blood is acceptable for CMV detection

5-10 mL - Heparinized, citrated, or ethylene diaminetetraacetic acid (EDTA)

__ and __ should be used for samples collected for nucleic acid testing, because other anticoagulants may interfere with the enzyme functions required for PCR amplification. Serum may be used for ___ and ____

EDTA and Citrated blood - serologic tests and nucleic acid assays

For BONE MARROW __ or __ anticoagulants are acceptable for culture __ and ___ for nucleic acid testing

Heparin or EDTA EDTA and ACD

Useful for detecting viruses that commonly infect the lungs (___,___,__,__), brain (___), and gastrointestinal tract (__). Collected during surgical procedures. - ___ is preferred for nucleic acid assays, but __ and ___ may be used after removal of the paraffin (deparaffinization) and extraction

Tissue - CMV, influenza virus, adenovirus, sin nombre virus - HSV - CMV - Fresh TISSUE - formalin-fixed and paraffin-embedded tissues

GENITAL SPECIMENS Detection of __ and __ Must be place in appropriate VTM

HSV and HPV

should be used for ulcerations and placed in appropriate viral transport media.

Genital swabs

may be collected using a swab or brush and placed in viral transport media. Some manufactured __ or ___ are appropriate for nucleic acid testing

Cervical specimens - endocervical or liquid-based cytology devices

__ and ___ specimens may be needed to detect antibody to specific viruses - Acute specimens should be collected as soon as possible after the appearance of symptoms

Acute and convalescent serum

is collected a minimum of 2 to 3 weeks after the acute specimen

Convalescent specimen

Appropriate specimen is ___ of serum collected by venipuncture.

3 to 5 mL

Throat and Nasopharynx

Respiratory: 1 Adenoviruses Y 2 Parainfluenza virus Y 3 Influenza virus W 4 Respiratory syncytial virus W 5 Metapneumovirus W 6 SARS coronavirus W

nasal:+++ in respiratory

Rhinoviruses y

(other:serum) in respiratory

Sin nombre virus sp, s

Dermatologic and mucous membrane vesicular Throat and Nasopharynx Stool Vesicle fluid or scrapping

Entero virus S F

Dermatologic and mucous membrane vesicular Vesicle fluid or scrapping

Herpes simplex virus Y Moknkeypox Y

Dermatologic and mucous membrane vesicular Throat and Nasopharynx Vesicle fluid or scrapping

Varicella zoster virus Y

Dermatologic and mucous membrane Exanthematous Throat and Nasopharynx Stool

Enterovirus S

Dermatologic and mucous membrane Exanthematous Throat and Nasopharynx Urine Serum

Measles Y

Dermatologic and mucous membrane Exanthematous Urine Serum

Rubella Y

Dermatologic and mucous membrane Exanthematous Serum Amniotic fluid

Parvoviirus Y

Dermatologic and mucous membrane Pustular/Nodular Tissue

Molluscum contagiosum, orf Y

Dermatologic and mucous membrane Pustular/Nodular Tissue/ cells, thin prep

Warts Y

Dermatologic and mucous membrane Pustular/Nodular cervical

Papillomavirus

Meningoencephalitis/encephalitis CSF and Serum

Arboviruses S, F

Meningoencephalitis/encephalitis Throat and Nasopharynx CSF Urine

Enteroviruses S, F

Meningoencephalitis/encephalitis CSF Brain biopsy

Herpes simplex virus Y

Meningoencephalitis/encephalitis Serum

Lymphocytic choriomeningitis Y Mumps virus Y

Meningoencephalitis/encephalitis Brain biopsy

HIV Y Polyomavirus (JC virus) Y

Meningoencephalitis/encephalitis Corneal cels, brain

Rabies virus

Gastrointestinal dse Stool

Adenoviruses (serotypes 40-41) Y Noroviruses S Rotavirus W, SP

Myocarditis, Pericarditis, and Pleurodynia Throat and nasopharynx csf pericardial fluid

CoxsackieB S, F

Hemorrhagic fevers Tissue, respiratory secretions and serum

Ebola/Malburg viruses Y

Hemorrhagic fevers Throat and nasopharynx URINE Throat washes, serum

Lassa fever virus

Hepatitis blood

Hepatitis Y

Dermatologic and Mucous membrane Congenital and Perinatal Throat/Nasopharynx CSF Urine

Enterovirus S

Dermatologic and Mucous membrane Congenital and Perinatal Vesicle fluid

Herpes simplex virus Y

Dermatologic and Mucous membrane Congenital and Perinatal Amniotic fluid, liver tissue

Parvovirus Y

Dermatologic and Mucous membrane Congenital and Perinatal Urine serum

CMV Y Rubella Y Zika Y

Dermatologic and Mucous membrane Eye (Ocular dse) Throat and nasopharynx conjunctival swab or scraping

Adenoviruses Y

Dermatologic and Mucous membrane Eye (Ocular dse) conjunctival swab or scraping

Herpes simplex virus Y Varicella- zoster virus Y

Dermatologic and Mucous membrane Post transplantation syndrome urine blood tissue

Cytomegalovirus Y

Dermatologic and Mucous membrane Post transplantation syndrome Blood tissue

Epstein barr virus Y

Dermatologic and Mucous membrane Post transplantation syndrome BLOOD

Human herpesvirus-6 Y

Dermatologic and Mucous membrane Post transplantation syndrome Tissue

herpes simplex Y

Since the viruses are obligate intracellular parasites, they cannot be grown on any inanimate culture medium Viruses can be cultivated within suitable hosts, such as a___

living celL

The primary purposes of viral cultivation are: 1 2 3

1. To isolate and identify viruses in clinical specimens 2. To prepare viruses for vaccines 3. And to do detailed research on viral structure, multiplication cycles, genetics, and effects on host cells

The earliest method for the cultivation of viruses causing human diseases was inoculation into human volunteers. >___ and ___ used human volunteers for their pioneering work on yellow fever. - Due to serious risk involved, human volunteers are used only when no other method is available and when the virus is relatively harmless

Reed and colleagues (1900)

LABORATORY DIAGNOSIS OF VIRAL INFECTION

I. Identification of the virus in cell culture II. Microscopic identification in the specimen III. Serological procedures to detect a rise in antibody titer IV. Detection of viral antigen in blood or body fluids V. Detection of viral nucleic acids

METHODS OF VIRAL ISOLATION

1. Animal Inoculation 2. Embryonated Egg Inoculation 3. Tissue Culture

Primary isolation of certain viruses * For the study of pathogenesis, immune response and epidemiology of viral diseases * For the study oF ___

Animal Inoculation - oncogenesis

Laboratory animals play an essential role in studies of viral pathogenesis * __ AND ___ -Monkeys for the isolation of poliovirus * ____ -white mice * monkeys, mice, rabbits, guinea pigs, ferrets

Animal Inoculation - Landsteiner and Popper (1909) - Theiler (1903)

limited application in virology

Monkey

Infant: Routes of inoculation of Animal inoculation: ____,___,___,___ Death, disease or visible lesions

Suckling mice Coxsackie and arbovirus Intracerebral, subcutaneous, intraperitoneal, intranasal

Animal Inoculation Disadvantages 1 2 3 4 5

1. Costly 2. Maintenance 3. Interference of immune system 4. Individual variations 5. Difficulty in choosing of animals for particular virus

____, further developed by Burnet * 8-11 days old * Incubated for 2-9 days

Embryonated Egg Inoculation Goodpasture (1931)

Eggs provide a suitable means for: 1 2 3

* the primary isolation and identification of viruses * the maintenance of stock cultures * and the production of vaccines

Embryonated Egg Inoculation Routes of Inoculation 1 2 3 4

1. Chorioallantoic membrane(CAM) 2. Amniotic Cavity 3. Allantoic Cavity 4. Yolk sac

Has been widely used in veterinary virology * Viruses grow readily or can be adapted to grow on it * Produces visible lesions ____ * ____, can be used for the assay of pock- forming viruses * Different viruses have different pock morphology

Chorioallantoic Membrane (CAM) - (pocks) - Pock counting

Most popular * Provides a rich yield of influenza and some paramyxoviruses for vaccine production * ___,__, __,___ * Fluid is examined for ___ or ____

Allantoic Cavity - Influenza Virus, Mumps Virus, Newcastle disease virus, Avian Adenovirus - turbidity or hemagglutination

Virus is introduced directly into it, that bathes the developing embryo * Volume of fluid in the infected____ * Recommended for the primary isolation of human viruses: 1 2 * Has little application in veterinary virology * Newly isolated influenza viruses may require several passages before they adapt to growth by other routes, such as ___

Amniotic Cavity - amniotic sac is small (1-2 ml) -Mumps virus *Influenza A, B and C viruses - allantoic

Simplest method for growth and multiplication of virus - __,__,__,__ * Immune interference mechanism can be detected in most __ viruses * Can also be used for the cultivation of __, and __

Yolk Sac - * Influenza, HSV, Vaccinia and some Arboviruses - avian -Chlamydia and Rickettsia

Process of holding a strong light above or below the egg to observe the embryo A candling lamp consists of a strong electric bulb covered by a plastic or aluminum container that has a handle and an aperture

Egg Candling

Detection of Viral Growth 1 2 3

* Death of the embryo * Defects in embryonic development * Localized areas of damage in the membranes (pocks)

A crucial technique in viral isolation that involved cultivating viruses in living cells or tissues. - Provides a controlled environment for studying replication, pathogenesis and development of antiviral drugs and vaccines

Tissue Culture

TYPES OF TISSUE CULTURES 1 2 3

1. Organ Culture 2. Explant Culture 3. Cell Culture

Small bits of organs can be maintained in ___ * Useful for the isolation of some viruses which appear to be highly specialized parasites of certain organs

Organ Culture - vitro

Fragments of minced tissue can be grown as ‘explant’ embedded in ___ * _____ were used for the isolation of adenoviruses

Explant Culture - plasma clots - Adenoid tissue explant culture

Routinely used * Dissociated using __ and ____ * Growth medium contains __,__,__,___ and a buffering system of ____ in equilibrium with atmosphere containing____

Cell Culture - proteolytic enzymes (trypsin) and mechanical shaking -essential amino acids, vitamins, salts, glucose -bicarbonate - 5% carbon dioxide

Supplemented with up to 5% calf or fetal calf serum * ___ to prevent bacterial contamination * ___ as indicator

Cell Culture -Antibiotics - Phenol red

CLASSIFICATION OF CELL CULTURES 3 Types based on:

Origin ▪ Chromosomal characteristics ▪ Number of generations through which they can be maintained

CLASSIFICATION OF CELL CULTURES 1 2 3

1. Primary Cell Cultures 2. Diploid Cell Lines 3. Continuous Cell Lines

Normal cells obtained from fresh organs of animals or human being and cultured. * Capable of only limited growth in culture and cannot be maintained in serial culture (1-2 passages) 1 2 3 * Commonly employed for primary isolation of viruses and in preparation of vaccine

Primary Cell Cultures - Monkey kidney cell culture. - Human embryonic kidney. - Chick embryo cell culture.

have complete set of chromosomes * Limited lifespan (___ serial passages) * Useful for isolation of some ___ and for the production of viral vaccines

Diploid Cell Lines 20-50 fastidious pathogens

Cells of a single type, usually derived from ____, that are capable of continuous serial cultivation indefinitely *__,__ and ___have been used in lab throughout the world for many years * Maintained by serial subcultivation or stored in ____ * Now permitted to be used for vaccine manufacture, for example, ____ for rabies vaccine

Continuous Cell Lines - cancer cells - Hela, hep-2 and KB cell lines - cold (–70°C) - vero cell

Primary cell cultures

Rhesus monkey kidney cell structure Human amnion cell culture Chick embryo fibroblast cell culture

Diploid cell strains

WI-38 (Human Embryonic lung cell strain) HL-8 (Rhesus embryo cell strain)

Continuous cell line

HeLA (Human carcinoma of cervix cell line) HEP-2 (Human epithelioma of larynx cell line) KB ( Human carcinoma nasopharynx cell line) McCoy (Human synovial carcinoma cell line) Detroit-6 (Sternal marrow cell line) Chang C/I/L/K (Human conjunctiva (c), Intestine (I) lIVER (L) Kidney (K) cell lines) Vero (Vervet monkey kidney cell line) BHL 21 (Baby Hamster kidney cell line)

- Derived from freshly isolated tissues or organs - Normal, diploid (46chromosomes) - limited (1-5 passages) -Slow growth, contact inhibition - Undergo senescence quickly

Primary Cell Cultures

Derived from normal, diploid cells Normal, diploid (46 chromosomes in humans) Finite (typically 20-50 population doublings) Slow growth, contact inhibition Undergo senescence after finite number of passages

Diploid Cell Lines

Derived from cancer cells or transformed cells Abnormal, aneuploid (variable number of chromosomes) Unlimited (can be maintained indefinitely) Rapid growth, loss of contact inhibition

Continuous Cell Lines

- Rapid modification of conventional cell culture - Involved culturing cells in a small, round-bottomed vial Inoculated with the clinical sample and then centrifuged to promote viral absorption. Incubated for ___

SHELL VIAL CELL CULTURE - 24 to 48 hours

DETECTION OF VIRUS GROWTH IN CELL CULTURE

1. Cytopathic effect 2. Metabolic inhibition 3. Hemadsorption 4. Interference 5. Transformation 6. Immunofluorescence 7. Detection of virus-specific nucleic acid 8. Detection of enzymes

components in an infected cell or abnormal accumulations of cellular materials resulting from virus-induced metabolic disruption.

Viral inclusions

-aggregates of cells fused to form one large cell with multiple nuclei

Syncytial cells

Presumptive identification of a virus isolated from a clinical specimen. Morphological changes in cultured cells

CYTOPATHIC EFFECT

Main Types of CPE 1 2 3 4 5

1. Rounding of cells - picornaviruses 2. Cell necrosis and lysis – Enteroviruses 3. Syncytium formation - measles, respiratory syncytial virus, human immunodeficiency virus (HIV) 4. Discrete focal degeneration - Herpes virus 5. Rounding and aggregation - Adenovirus

Quantification of cell cytopathic effects

Negative uninfected monolayer Equivocal +/- Atypical alteration of monolayer invoviving few cells 1+ 1-25% of monolayer exhibits cpe 2+ 25-50% of monolayer exhibits cpe 3+ 50-75% of monolayer exhibits cpe 4+ 76-100% of monolayer exhibits cpe

Viruses interfere with the metabolic activities of infected cells leading to reduction in cellular metabolic processes Changes in ___ in the culture medium. Normal cell cultures-medium turns __ Virus in cell culture-__

METABOLIC INHIBITION - pH - acidic - no acid production

Viral envelope proteins may bind glycoproteins expressed on the surface of erythrocytes Addition of guinea pig erythrocytes to the cultures - __ and ____

HEMADSORPTION - Influenza and parainfluenza viruses

Non-cytopathogenic virus tested with known cytopathogenic virus Growth of the first will inhibit the infection of the second virus by this Phenomenon for which a cell infected by a virus becomes resistant toward a second outcoming infection by a superinfectant virus

INTERFERENCE

Tumor forming (oncogenic) viruses Growth appears in a piled-up fashion producing microtumors 1 2 3 4 5

TRANSFORMATION Herpes viruses Adenoviruses Hepadnavirus Papovaviruses Retroviruses

Technique used to visualize and localize specific antigens (viral proteins) within cells. Gives positive results earlier than other methods ___

IMMUNOFLUORESCENCE - Fluorescein Isothiocyanate (FITC)

A single labeled antibody is used to directly detect the target viral antigen - More rapid but less sensitive - best suited to large quantities of virus are suspected or when high-quality, concentrated monoclonal antibodies are used

Direct Immunofluorescence

A primary antibody is followed by a labeled secondary antibody, amplifying the signal and increasing sensitivity used when lower quantities of virus are suspected, such as detection of respiratory viruses in specimens from adult patients

Indirect Immunofluorescence

Interpretation of Fluorescence intensity using fitc

Negative No apple green fluorescence 1+ Faint yet unequivocal apple green fluorescence 2+ Apple green fluorescence 3+ Bright apple green fluorescence 4+ Brilliant apple green fluorescence

Molecular-based assays, such as polymerase chain reaction Provide rapid, sensitive, and specific methods of detection

DETECTION OF VIRUS-SPECIFIC NUCLEIC ACID

Identified as reverse transcriptase in ___ , in the culture fluid. Using antibodies to detect viral antigens or antibodies in the culture medium

DETECTION OF ENZYMES - retroviruses

Powerful technique used to visualize at a very high resolution Study the structure, morphology and size of viral particles in detail

ELECTRON MICROSCOPY

- passes a beam of electrons through a thin specimen. The electron that pass through interact with the specimen, creating an image - Useful in studying the internal structure of viruses. It can reveal presence of ____,___ and ____

Transmission Electron Microscopy (TEM) - viral capsids, nucleic acid and other internal components

VIRAL ASSAY

1. Total virus particles 2. Infectious virion assay

Total virus particles

Electron microscopy Hemagglutination

Infectious virion assay

Quantal assays Quantitative infectivity assay

Direct virus counting with electron microscopy and latex particles

Electron Microscopy

Step 1: ____ -virus suspension is mixed with a negative stain Step 2:____-a known concentration of latex particles of a specific size is added to the virus suspension. The latex particles serve as a ___ Step 3:___ -The sample is examined under an electron microscope. The virus particles and latex particles can be distinguished based on their ___ and___ Step 4: ____ -virus particles and latex particles are counted in a specific area of the electron micrograph. The ratio between the two can be used to estimate the concentration of the virus particles in the original suspension

Electron Microscopy - Negative Staining - Latex Particle Addition - visual reference - Electron Microscopy - size and appearance - Counting

Used to measure the “all-or-none” response of a population of virus. Only indicates presence or absence of infectious viruses can be carried out in animals, eggs or tissue culture for those viruses

Quantal Assays

The virus sample is serially diluted to determine the lowest concentration that can still produce infection Destruction of the host cell, embryo or animal or the appearance of CPE in cell cultures

Quantal Assays

__ or __: The titer of the original virus suspension is expressed as the 50% infectious dose or the 50% lethal dose per milliliter

ID50 or LD50

A convenient method of quantitation for certain viruses particularly that possess hemagglutinin proteins - is not a very sensitive indicator of the presence of small amount of virus particles. - approximately ____ are required to produce macroscopic agglutination.

Hemagglutination - 107 influenza virions

Step 1: ____-Virus suspension is serially diluted Step 2: ____-fixed volume of red blood cell is added to each dilution incubate at ___ Step 3:___ -if virus concentration is high enough, red blood cells will clump together Step 4: ___-Highest dilution that still produces hemagglutination is determined

Hemagglutination - Virus Dilution - Red blood cell addition - 37°C - Observation of hemagglutination - Endpoint Determination

measure the actual number of infectious particles in the inoculum. Two methods are available 1 2

Quantitative Infectivity Assay - plaque assay in monolayer cell culture and pock assay on chick embryo CAM

Viral suspension is added to a monolayer of cultured cells in a bottle or petri dish allowing time for absorption, - Removed and replaced with a ___ to prevent virus spreading throughout the culture - Each infectious viral particle gives rise to a localized focus of infected cells that can be seen with the naked eye. -

PLAQUE ASSAY - solid agar gel

__ and ___, form pocks when inoculated onto the chorioallantoic membrane of an embryonated egg. - Such viruses can be assayed by counting the number of pocks formed on cam by appropriate inocula of virus

POCK ASSAY - Herpes and vaccinia

Each plaque represents ____ in the original virus sample.

1 infectious unit (virion or infected cell)

choriallantoic membrane inoculation

hsv pox virus rous sarcoma virus

amniotic inoculation

influenza mumps

yolk sac inoculation

hsv

allantoic inoculation

influenza mumps newcastle dse virus avian adenovirus

SPECIMEN COLLECTION AND CULTIVATION OF VIRUSES Flashcards

(141 cards)