Virus Flashcards
What is a virion?
Extracellular form of a virus which facilitates transmission from one host cell to another
How to classify viruses?
Order
Family
Genus
Species
How are viral families classified?
Based on genome structure
Mode of replication
Presence or absence of envelope
Describe the structure of virus
The nucleic acids with its associated polymerase
Trapped in a protein capsid
Trapped in a lipid envelope
With spike proteins like antigens
Describe viral replication
Virus attaches to the cell using spike protein (binds to receptor)
It leaves the protein coast outside
The genetic material is replicated
The spike proteins are copied and sent to the cell membrane
The nucleic acid reaches the membrane and leaves by exocytosis taking the spike proteins by budding
What is vertical transmission?
Transmitting pathogens from the parent to the child using breast milk or placenta … just right after birth
Give examples of zoonotic virus?
Rabies
Ebola
What are host ranges?
What range of animals are affected by the virus
Coinfection with humans and other species can result in new strains of the virus
What are the consequences of virus infection?
Overcome the virus and not get it again
Chronic gets worse over time like HIV
Latent infection
Transformation
What is latent infection?
You get the infection and recover
Then it comes back as the virus hid in the body and reactivated
The viral genome is in the host but it’s not produced hence not detected
What is a transformation infection?
The infection can transform into something more dangerous like a malignancy
What is an example of latent virus?
Chickenpox in children and shingles in adults
How can viral infections lead to cancer?
Modulation of apoptosis- virus stop this!
Modulation of cell cycle- virus causes excess proliferation
Can activate reactive oxygen species in the body
Examples of virus causing cancer diseases
HPV can cause cervical cancer
Hepatitis B and C
How to detect viruses?
Detect the whole organism
Detect parts of the organism
Detect the immune response to the pathogen
How can we detect virus as a whole organism?
Seeing the virus under the electron microscope but it’s not specific
Or cultures which show the damage the virus can cause… still non specific
How can we detect viruses as an antigen?
Lateral flow device
Add coloured or tagged specific antibodies
Detect the nucleic material using PCR by targeting the genome of the virus which is specific
How can we detect a viral immune response?
Same as antigen but can use IgM and IgG testing
What does IgM mean?
Indicates a current infection
What does IgG mean?
Presence of infection now or prior
All antivirals are virucidal. True or Falsekl
False
All are virustatic none are virucidal
Because then we need to kill the host cell
What types of viral immunisations are there?
Vaccinations
Passive immunisation with immunoglobulins
What is prophylaxis
A treatment to prevent disease.
Common with respiratory infections for the elderly
What other measure can be taken in regards to viral infection control?
Screening like antenatal screening to protect the mother and the child
Testing
Social distancing
