Introduction to Viruses Flashcards
Why are viruses parasitic?
They need a host to survive
What does icosahedral mean?
It has 20 faces (in equilateral triangle)
What shape is viral DNA and RNA
helical
What does tissue tropism mean?
Most viruses have specific host range and only infect specific host cell types
What is the taxonomy of the virus?
order: mononegavirales
family: foloviridae
genus: ebolavirus
species: zaire ebolavirus
Viruses can be classified according to…(4)
- virion shape/symmetry
- presence/absence of envelope
- genome structure
- mode of replication
What nucleic acid is found inside the virus?
DNA or RNA
what structure protects DNA inside virus?
capsid
What do spike projections allow the virus to do?
develop natural immunity
What do glycoproteins on the virus surface allow it to do?
bind to receptor sites on host’s membrane (the viral envelope can the fuse with the host’s membrane to transfer viral genome)
what are steps for virus replication?
- virus attaches to cell
- genetic material enters host cell
- genetic material is uncoated
- genetic material passes into the nucleus
- more copies of genetic material are made
- cell lyses releasing more viruses
What are the 7 transmission mechanisms in humans which are involved in viral transmission?
- blood-borne
- droplet
- airborne
- vertical (mother to child)
- sexual
- close contact
- faecal-oral
What are 3 transmission mechanisms using other species to transmit viral infections?
- vector-borne(involves vectors like insects)
2. zoonotic (through animals)
what are 3 common zoonotic viruses?
- rabies
- MERS (middle east respiratory syndrome)
- ebola
what are 3 common blood borne viruses?
HIV, hep B and hep C
what are 2 common sexual viruses?
HIV, hep B (and other STIs)
what are 2 common vertical viruses?
HIV, hep B
What are 2 common droplet viruses?
influenza, RSV (respiratory, syncytial virus)