cultivating viruses Flashcards
Viruses require living cells as their
“medium
laboratory-bred animals and embryonic bird tissues
In vivo:
cell or tissue culture methods
In vitro
Primary purposes of viral cultivation:
Isolate and identify viruses in clinical specimens.
Prepare viruses for vaccines.
Do detailed research on viral culture, multiplication cycles, genetics, and effects on host cells.
usual choices for viral cultivation
Specially bred strains of white mice, rats, hamsters, guinea pigs, and rabbits
- invertebrates such as insects or non-human primates are used
- Because viruses exhibit host specificity, certain animals can propagate viruses more readily than others.
Why do some cltivating methods require using bird embryos?
intact and self-supporting unit
sterile environment
contain their own nourishment
Bird eggs ex
Chicken, duck, and turkey eggs are the most common choices for inoculation
How is virus injected into bird embryos?
Virus is injected through the eggshell by drilling a small hole or making a small window.
Isolated animal cells are grown in vitro in cell or tissue culture rather than in an animal or egg.
List the reasons
Grown in sterile chambers with special media that contain the correct nutrients for cells to survive
Cells form a monolayer, or single, confluent sheet of cells that supports viral multiplication.
Allows for the close inspection of culture for signs of infection
areas where virus-infected cells have been destroyed and show up as a clear, well-defined patches in the cell sheet
Microscopic manifestation of cytopathic effects (CPEs)
plaques
Name two noncellular infectious agents besides viruses.
Spongiform encephalopathies:
and
Prions:
Implicated in chronic, persistent diseases in humans and animals
Brain tissue removed from affected animals resembles a sponge
Long period of latency before first clinical signs appear
Diseases are progressive and universally fatal
Spongiform encephalopathies
Agents of spongiform encephalitis infection
Deposited as long protein fibrils in the brain with no nucleic acid
Creutzfeldt-Jakob disease - affect CNS, cause gradual degeneration and death
Bovine spongiform encephalopathy (BSE)
Prions:
Name the Satellite Viruses
Adeno-associated virus (AAV):
Delta agent:
Originally thought that it could only replicate in cells infected with the adenovirus
Can also infect cells that are infected with other viruses or that have had their DNA disrupted through other means
Adeno-associated virus (AAV):
