Virology Flashcards
Define Virology
Study of viruses
Which cell are the viruses unable to grow outside?
Host
Describe the cell where the viruses are unable to grow outside
Living
Describe the viruses
Obligate intracellular
What do these viruses require a living cell for?
2 points
Survival
Replication
Where are these viruses propagated on?
Tissue culture
Where aren’t these viruses propagated on?
Culture media
Describe this culture media (2 points)
Ordinary
Artificial
What is the viral particle known as?
Virion
What does each viral particle consist of?
Nucleic acid
Describe this Nucleic acid
Genetic material
What are the 2 genetic materials where each viral particle consist of?
DNA
Or
RNA
What are these DNA or RNA known as?
Genome
Describe this part
Infectious
What does the genome code for?
Proteins
Which proteins does the genome code for?
Enzymes
What are these proteins necessary for?
Replication
What are the 2 forms of these proteins?
Non-structural
Structural
What is an example of a non-structural protein?
Nucleic acid polymerase
Which parts does the structural protein form?
Virion
Where are these genetic materials found in?
Protein coat/shell
Describe this protein coat/shell
Protective
What is this protective protein coat/shell known as?
Capsid
What does the capsid do with the genetic material?
Encloses it
What is the capsid and the nucleic acid together known as?
Nucleocapsid
What are the 4 functions of the capsid?
Protection
Attachment
Antigenic
Gives morphology
What does this capsid protect?
Genome
What does the virus use this capsid to attach to?
Host cell receptor
Which mediated responses are directed against this capsid? (2 points)
Cellular
Humoral
Which feature of the capsid in which these mediated responses are directed against?
Proteins
What this capsid be?
Enveloped
What do some viruses acquire from the host?
Outer lipoprotein coat
Through what feature of the host do these viruses acquire this outer lipoprotein coat from?
Cell membrane
Describe this membrane (2 points)
Nuclear
Or
Cytoplasmic
How do these viruses acquire this outer lipoprotein coat from the host cell membrane?
Budding
What does this cell membrane always contain?
Glycoproteins
Describe these glycoproteins
Unique
What are the enveloped viruses sensitive to?
Lipid solvent
Describe the size of the viruses
Small
What unit is used to measure the viruses?
Nanometer
What is the size range of the viruses?
20-300
Which microscope are the viruses only visualized by?
Electron
What are the viruses eliminated by?
Immune system
What doesn’t have an effect on the viruses?
Antibiotics
What are the viruses treated by?
Antiviral drugs
What can prevent viral infections?
Vaccines
What do these vaccines produce?
Lifelong immunity
What are the 3 characteristic shapes of the viruses?
Spherical
Helical
Polyhedron
What is the most common Polyhedron?
Icosahedron
What does the icosahedron have?
Triangular faces
How many triangular faces does the icosahedron have?
20
What do these viruses sometimes have?
2 points
Tails
Envelopes
What are the 7 principle events involved in the replication?
Adsorption Penetration Uncoating Eclipse phase Synthesis
Assembly
Or
Maturation
Release
What is the first step in infection of a cell which is involved in the adsorption?
Attachment
What does this virus attach to?
Cell surface
What is recognized outside the cell ,on its surface?
Specific receptors
What feature of a virus attaches to these specific receptors that are found outside the cell , on its surface?
Protein
What are the 2 ways of penetration?
Fusion
Endocytosis
Which viruses are involved in the fusion?
Enveloped
What do these viruses fuse directly with?
Plasma membrane
Which viruses are involved in the endocytosis?
Non-enveloped
What do these non-enveloped viruses enter the cell by?
Invagination
What is this invagination of?
Cell membrane
What do these viruses form when they enter the cell by the invaginations of the cell membrane?
Vesicles
Where are these vesicles formed in the cell?
Cytoplasm
What is released in the uncoating of the virus?
Genome
Where is this genome released form?
Capsid
What is enabled as the genome is released from the capsid?
Replication
What starts this replication?
Nucleic acid
What cannot be recovered from the cell in the eclipse phase when the nucleic acid is uncoated?
Infectious virions
What do the unrecovered infectious virions last until?
New virions are made
What is synthesized in the virus replication?
2 points
Nucleic acid
Proteins
What occurs in the synthesis of the nucleic acid and proteins?
Transcription
What is transcribed in the synthesis of the nucleic acid and proteins?
mRNA
What is this mRNA transcribed from?
DNA
What does this mRNA code for?
Proteins
What happens to these proteins?
Translation
Where are these proteins translated by?
Host cell
What are the 3 proteins that the mRNA codes for?
Early
Late
Nucleic acid
Describe the early proteins
Non-structural
Describe the late proteins (2 points)
Structural
Building blocks
What are these late proteins building blocks for?
Virion
What does the nucleic acid undergo?
Replication
What does the nucleic acid produce when it undergoes replication?
New genomes
What are assembled?
New virions
What is released in the final stage of the virus replication?
New infectious virions
What are the 2 ways in which these new infectious virions are released?
Budding
Lytic
What does the budding occur from?
Cell surface
Which viruses make budding?
Enveloped
What isn’t done to the cell by the budding viruses?
Killing
What does the lysis occur in?
Infected cell
Which viruses make this lysis?
Non-enveloped
What are the 2 ways in which the virus can be transmitted by?
From person to person
From animal to person
What is the transmission of the virus from animal to person known as?
Zoonosis
What are the 2 ways in which the virus is transmitted by from person to person?
Horizontal
Vertical
What is the person exposed to causing horizontal transmission? (6 points)
Respiratory secretions Saliva Blood Semen Fecal contamination Sexual transmission
What are the 2 respiratory secretions?
Airborne
Droplets
Through what is the person exposed to the infection from blood? (2 points)
Transfusion
Needle sharing
What is the fecal contamination of? (2 points)
Food
Water
Describe the occurrence of vertical transmission
Maternal to fetal/child
What does the vertical transmission occur across?
Placenta
During what does the vertical transmission occur?
Breast feeding
What are the 2 ways of animal to person transmission?
Direct
Indirect
Describe the direct transmission of the infection from the animal to the person
When infected animals is exposed to human
What is the indirect transmission of infection from animal to person?
Arthropod-borne
What does the arthropod-borne done by?
Arbovirus
What does the most common arthropod-borne transmission done by?
Mosquito
What does the less common arthropod-borne transmission done by?
Ticks
What are the 5 types of viral infection?
Subclinical
Acute
Persistent
Latent Transformation
What is the most common viral infection?
Subclinical
What aren’t present in the subclinical infections?
Sings
Symptoms
Describe these signs and symptoms
Clinical
What is the acute infection also known as?
Lytic
What does the acute infection result in?
2 points
Destruction
Death
What are destroyed and dead due to the acute infection?
Host cells
What are the 2 types of acute infection?
Local
Systemic
What is an example of a virus that causes local acute infection?
Rhinovirus
Describe the mode of transmission of viruses that cause local acute infection
Respiratory
What is the site of lesion caused by these viruses?
Portal of entry
Describe the incubation period of the local acute infection
Short
Describe the duration of immunity of local acute infection
Short
Describe the role of igA in the local acute infection
Important
What is absent in the local acute infection?
Viremia
What is an example of a virus that causes systemic acute infection?
Measles
Describe the mode of transmission of viruses that cause systemic acute infection
Respiratory
Describe the site of lesion caused by these viruses
Distant
Describe the incubation period of the systemic acute infection
Long
Describe the duration of immunity of systemic acute infection
Life long
Describe the role of IgA in systemic acute infection
Not important
What is present in the systemic acute infection?
Viremia
Describe the persistent infection
Chronic
What may not occur to the host cell in the persistent infection?
Lysis
Describe the time in which this infection occurs over
Long period
Which virus causes this persistent infection?
Replicating
What is an example of this virus?
Hepatitis B
What doesn’t the virus undergo in the latent infection?
Replication
What is present between the infection and the appearance of the symptoms?
Delay
Describe the viruses in the latent infection
Dormant
Which factors of the host trigger this dormant virus?
Stress
What is an example of a virus that causes persistent infection?
Herpes virus
What is the normal cell changed to in the transformation infection?
Tumor
Which viruses are able to change the normal cell into a tumor?
Animal
What is an example of these viruses?
Oncogenic viruses
What are the 3 diagnostic methods in virology?
Direct detection
Isolation
Serological
What are directly detected? (3 points)
Virion
Antigen
Nucleic acid
Which virus is islolated?
Of clinical specimen
Where is the virus of clinical specimen isolated in? (3 points)
Cell culture
Eggs
Animals
Which diagnostic method of virology is used by the majority of common viruses?
Serology
What are the 5 direct examinations of specimen?
Electron microscopy Immune electron microscopy Light microscopy Antigen detection Molecular techniques
What is the electron microscopy required for?
2 points
Visualization
Detection
What 2 features of viruses are identified by the electron microscopy?
Morphology
Size
Which viruses are also detected by the electron microscopy?
That cannot be cultured
What is used in the immune electron microscopy?
Specific antibody
What is this specific antibody used for ?
Agglutination
What is does this specific antibody agglutinate together?
Virions
What is made easy as a result for these virions?
Recognition
What 2 features of the electron microscopy are enhanced when the virus specific antibody is used?
Sensitivity
Specificity
What feature of the viruses are detected and stained by the light microscopy?
Inclusion bodies
What are the inclusion bodies?
Accumulation of virions
Which site are these virions accumulated at?
Assembly
What is an example of these inclusion bodies?
Negri bodies
Which infection is where these Negri bodies seen in?
Rabies
What are used to detect viral antigens?
Serological techniques
What are the 4 serological techniques used to detect viral antigens?
Precipitation
Agglutination
Immunofluorescence
ELISA
Which viruses are also detected by their antigens?
That cannot be cultured
Which feature of viruses is detected by molecular techniques?
Genome
What are the 2 ways used to detect the viral genome?
Nucleic acid hybridization
Polymerase chain reaction
What is the polymerase chain reaction known as?
PCR
Which viruses are also detected by their genome?
That cannot be cultured
What are used for viral isolation in order for it to replicate? (3 points)
Tissue cell cultures
Fertilized eggs
Laboratory animals
What are the most common method for virus isolation in most laboratories?
Tissue cell cultures
What are these tissue cell cultures separated into? (3 points)
Primary cells
Semi-continuous diploid cells
Continuous cells
Describe the primary cells (2 points)
Normal
Adult
How many times can these cells be passaged?
2 points
Once
Or
Twice
What is an example of these primary cells?
Monkey kidney
What are the semi-continuous diploid cells taken from?
Embryonic tissue
How many times are these cells passaged?
Up to 50
What is an example of these semi-continuous diploid cells?
Human embryonic kidney
Describe the continuous cells
Immortalized
What are the 2 examples of these continuous cells?
Tumor cell lines
Hela cell
Which tissues are these tumor cell lines derived from? (2 points)
Human
Or
Animal
Describe the passage of these tumor cell lines
Indefinite
Where are the hela cells obtained from?
Carcinoma
What is this carcinoma of?
Cervix
What are inoculated with suitable clinical specimens?
Cell monolayers
What are these cells then observed for?
Cytological changes
What feature of viruses is indicated by these cytological changes?
Growth
What are detected for viral infected cell?
9 points
Plaque formation Cytopathic effect Inclusion body formation Direct fluorescent antibody stain Antigens Haemadsorption Interference Morphologic transformation Neutralization test
Which localized areas are the plaque formed in?
Of destructed cell
Where is this destructed cell in?
Monolayer culture
What are used for the plaques to appear?
Vital stains
What do these plaques appear as with the vital stains?
Unstained areas
Where are these unstained areas appear on?
Colored background
What is each plaque a result of?
Infection
How many cells are infected?
One
How many viruses infect this one cell?
One
What are the cytopathic effects known as?
CPE
Describe these cytopathic effects
Destructive
What feature of a virus causes microscopic destructive effects?
Growth
Which site is also detected instead of the inclusion body?
Replication
Which 2 stains are used to detect these inclusion bodies?
Hematoxylin
Eosin
Describe the hematoxylin dye
Basic
Describe the eosin dye
Acidic
Which microscope is used to see these inclusion bodies?
Light
What are the antigens?
Proteins
Describe the viral antigens (2 points)
Soluble
Specific
What are these antigens generally detected by?
Specific antibodies
Which protein is detected by these specific antibodies?
Of interest
What are the 2 tests used to detect these antigens?
Compliment fixation
Hemagglutination
What is adsorbed in hemadsorption?
Erythrocytes
Which cells are these erythrocytes adsorbed to?
Virally-infected
Describe this reactive before any visible cytopathic changes
Positive
What are the 2 viruses that are mainly detected by the hemadsorption?
Influenza
Parainfluenza
Which virus is interfered?
Known non-cytopathic
What is this virus used to interfere with?
Replication
Which virus replication is interfered by the known non-cytopathic virus?
Cytopathic
Where is the cytopathic virus replication interfered by the known non-cytopathic virus?
Infected cell
Which viruses is the morphological transformation associated with the infection of?
Oncogenic
What is lacked in the morphological transformation?
Contact inhibition
What is neutralized in the neutralization test?
CPE
What are used to neutralize the CPE?
Specific antisera
What is detected so that Serological diagnosis is done? (3 points)
Increased antibody titers
IgM
Sero-conversion
When does the IgM detected?
Recent infection
What is changed in Sero-conversion?
Antibody state
Which antibody state is changed in Sero-conversion?
Negative
To which antibody state is changed in Sero-conversion?
Positive
What are the 6 commonly used Serological tests?
Enzyme linked immunosorbent assay (EIA) Western blot (WB) Immunofluorescence techniques (IF) Complement fixation tests Hemagglutination inhibition tests Neutralization tests
What do the Antiviral drugs target in the viral life cycle?
Steps
When are the 2 steps that the Antiviral drugs target in the viral life cycle?
Before cell entry
During viral replication
What does the drug do with the ability of a virus to enter a target cell ,before cell entry?
Interference
What could the drug be similar to in a host cell so that it can interfere with the ability of a virus to enter a target cell?
Receptor
What else does the drug do in order to interfere with the ability of a virus to enter a target cell?
Inhibition
What feature of a virus is inhibited by the drug in order to interfere with the ability of a virus to enter a target cell?
Uncoating
What are the 2 viruses that use these 2 ways to interfere with the ability of a virus to enter a target cell?
Amantadine
Rimantadine
What is disease where Amantadine and Rimantadine treat and prevent?
Influenza
What are involved the steps during viral replication which the Antiviral drug target? (4 points)
Nucleoside analogues
Protease inhibitors
Interferons
Release phase
What do the Nucleoside analogues look like? (2 points)
RNA
DNA
What do the Nucleoside analogues do as a result of their similar appearance to RNA or DNA?
Deactivation
What do they deactivate?
Enzymes
What are the 3 Nucleoside analogues that deactivate the enzymes?
Acyclovir guanine
Zidovudine (AZT)
Ribavirin
Which infections is the Acyclovir guanine effective analogue?
Herpes
What is a type of Zidovudine (AZT) analogue?
Thymidine
Which enzyme does the Thymidine inhibit?
Reverse transcriptase
Which virus has this Reverse transcriptase enzyme?
HIV
What are used in the treatment of HIV infection? (2 points)
Reverse transcriptase inhibitors
Protease inhibitors
What are the 2 protease inhibitors that deactivate the enzymes?
Indinavir
Saquinavir
Which virus do Indinavir and Saquinavir target their stage of replication?
HIV
Which stage of replication do Indinavir and Saquinavir inhibit?
Late
What do the interferons inhibit so that they can inhibit viral replication?
mRNA
What release is prevented by the Antiviral drugs in the release phase?
Virions
What is an example of an Antiviral drugs that prevent the release of virions in the release phase?
Oseltamivir
What is a type of Oseltamivir that prevent the release of virions in the release phase?
Tamiflu
What does the Oseltamivir treat?
Influenza
