RNA Viruses -Saviola Flashcards
Do DNA or RNA viruses mutate faster?
RNA viruses
What are some commonalities between the RNA viruses?
replicate in the cytoplasm
require as RNA-dependent RNA polymerases
viruses show a high mutation frequency
Their genetic material replicates by synthesis of complementary RNA, and DNA is not involved
What kind of virus is rotavirus? How is it transmitted?
naked
double stranded RNA virus
fecal-oral
*story about school getting sick because cooks not washing hands properly
What do retroviruses require?
RNA dependent DNA polymerase
Reverse transcriptase
What are the 3 groups of picornaviridae? What are common characteristics of these groups?
enteroviruses, hepA, rhinovirus
cytolytic and naked
transmitted fecal-oral (except for rhinovirus)
What are some characteristics of poliomyelitis?
polio is an enterovirus
replicates in the motor neurons of the anterior horn of the spinal cord and brain stem. May involve meninges and produce permanent paralysis (flaccid paralysis)
Virus multiplies in neurons and kills them
fecal-oral transmission. used to be more prevalent in summer and early fall–> swimming pools** can transmit fecal-oral if not properly chlorinated (story about Roman baths)
hearty because it is naked
live attenuated vaccine more effective but can revert back to a virulent form and cause polio –> use the enhanced inactivated vaccine normally
What percentage of people with poliovirus get non paralytic aseptic meningitis? flaccid paralysis?
in 1-2 % of people it causes nonparylytic aseptic meningitis, and in less than 1% of people it results in flaccid paralysis.
What are some characteristics of Hep A?
lives in the liver –> acute hepatitis
not cytolytic and doesn’t release by budding
transmitted fecal oral
How is Hep A different from Hep B?
Hep B causes chronic hepatitis (and Hep C)
Hep A only causes acute hepatitis
Hep A is also fecal oral while Hep B is blood or sexually transmitted (*story about LA restaurant giving people Hep A because not proper hand washing)
Why is rhinovirus different from the other picorna viruses?
it is acid labile–> can’t live in gut
likes to live in the nose because also temperature sensitive.
200+ serotypes–> can’t have vaccine
What are 3 causes of the common cold?
rhinovirus and adenovirus and coronaviridae
What are characteristics of caliciviridae (calix-cup) viruses? What are the 2 viruses in this category?
naked icosahedral nucleocapsids, slightly larger than picornaviruses, and differ in macromolecule synthesis
- Norovirus- fecal-oral transmission, 60% of non bacterial gastroenteritis can be attributed to Norwalk like viruses. (*story about cruise ships –>norovirus outbreak–> very transmissible via improper hand washing)
- Hepatitis E virus: fecal-oral fairly similar to the calciviruses. It causes epidemic outbreaks of acute hepatitis in parts of the world with poor sanitation. Deadly for pregnant women (similar to Hep A)
Which other Hepatitis is Hep E similar to? How are they similar?
Hep A
fecal oral transmission
cause acute hepatitis (not chronic)
what families have arboviruses in within them?
Togaviridae and flaviviridae
arbovirus=arthropod virus (can be transmitted by mosquitos)
What are some characteristics of Rubella?
togoviridae
spreads through respiratory and can can get into blood and affect the fetus of pregnant women
(cause cataracts, deafness, congenital heart disease, developmental defect, rubella rash)
if woman vaccinated or exposed to rubella previously, fetus will not be affected
there is a good live attenuated vaccine (MMR vaccine) that is given to children and women of child bearing age
what are some characteristics of Hepatitis C virus?
flavivirus
sexually transmitted or through blood
enveloped –> bud off hepatocytes
cause chronic hepatitis (70% cases are chronic)