Introduction To Virology Flashcards
how is measles transmitted?
- aerosols through cough and sneezes
- highly contagious!
measles treatment?
sterilizing vaccination (vaccine = no infection at all)
MMR vax
what is the influenza virus? treatments/symptoms?
indiscriminant
transmissible
flu vaccine
transmission of zika virus? symptoms?
easy insect transmission; expectant mother to fetus causes neurological implications (microcephaly - larger head)
We are all likely infected (for life) by a
herpes virus (2 subtypes)
viruses infect all
living things
what is a calicivirus?
infection of what causing rashes, gastroenteritis (excreting and shedding)
Our own genetic code contains
viral genes (or elements) integrated
About 10% of your DNA is derived from
retroviruses
endogenous viral sequences are remenants of infections from mya (not infectious)
example of exogenous and endogenous retrovirus?
HERVs (human endogenous retrovirus - found in human genome)
HIV
what are the 3 levels of defense mechanisms?
intrinsic (skin)
virus enters through cavities
innate immunity
mech to evade response
acquired immunity
Examples of viruses being good?
- Polydnaviruses: parasitoid wasp + caterpillars
- Curvularia protuberata: helps fungus
- Potyvirus: colourful tulips
Viral genomes are — and can only surive after —
obligate molecular parasites
…
they replicate in a host cell
Viruses must make — that can be translated by —. Thus, they use the host protein synthesis machinery to make —.
mRNA
…
host ribosomes
…
viral proteins
relationship between polydnavirus, wasps and caterpillars?
- Female wasps lay eggs inside living insect larva, also deposits her polydnavirus virus genome sequences
- Innate immune system of larva would normally kill the egg, preventing its development
- Elements of the polydnavirus virus genome expressed by the wasp suppress this innate immune response
SYMBIOGENIC: wasp + virus
example of good virus
relationship between Curvularia protuberata fungus, and curvularia thermal tolerance virus (CThTV)?
- Dichanthelium lanuginosum (plant) grows in geothermal soils at temperatures over 50C
- Fungus Curvularia protuberata permits plant survival but fungus can’t grow at T > 50 degrees
- Fungal thermotolerance is mediated by the curvularia thermal tolerance virus (CThTV)
ex. of good virus
relationship between potyvirus and tulips?
a potyvirus, Tulip breaking virus (TBV) results in the pattern bc TBV interferes with the synthesis of pigments
In order for viruses to survive they must:
- Package viral genome inside a particle
- Use particle to transfer their genome from host to host
- Genome contains info to initiate and complete the viral infectious cycle
- Genomes establish themselves in host ensuring long term viral survival
- obligate intracellular parasites
- make mRNA that can be translated by host ribosomes
The GENOME is key !!!
PTIHG
viruses are make a lot of mutations bc…
they replicate a lot making some successful mutants
What could happen if viruses always killed their hosts?
virus has no host to replicate in
What would happen if the virus did not evade the host defense system?
no replication bc VIRUS ALWAYS needs a host
Viruses have most likely existed for over
250 million years
example of beginning of viruses?
ancient romans had herpes (stop public kissing to avoid transmission)
What was the experiment done on Tobacco mosaic virus (TMV)?
conclusion about virus??
- late 1800s scientists crush TMV leaves and filter into tube
- thought pathogen would be in filter cell debris bc bacteria are large (put cell debris on leaf) and nothing happened
- put liquid filtrate that moves through the filter and leaf dies (viruses are smaller)
viruses = “filterable” species
how can viruses be seen?
electron microscopy
under 0.2 micron filter
large virus example? how can these viruses be seen? what is its host?
mimivirus under light microscope
doesn’t filter through 0.2 micron filter
host is amobea
Viruses are — the size of E.Coli
~ 1/1,000
