Case Study Comparison Chart: Polio Flashcards
what is the full name for polio?
poliomyelitis
what is the causative agent of poliomyelitis
polio virus
describe the structure of polio virus (4)
- icosahedral
- ss+RNA (does not package replicase)
- nkd (resists degradation and can withstand stomach acid)
- enterovirus (oral-fecal route)
describe the different stages of a polio infection (4)
- digestive tract
- lymphatic stage
- viremia stage (blood), crosses blood-brain barrier to
- neural stage (CNS)
describe the general distribution (%) of polio symptoms
99% of people are asymptomatic or mild symptoms
1% get paralytic polio
can asymptomatic people transmit polio? if so, how and for how long?
yes. in feces, for 4-6 weeks.
how to detect virus in fecal sample?
direct ELISA test
describe some symptoms of paralytic polio (4 groups)
- muscle weakness (atrophy)
- flaccid paralysis in limbs and chest
- headache, fever, stiffness in neck (inflammation)
- GI symptoms
what happens to an infected motor neuron? why is that significant?
it dies, cutting off the signals to muscles
why is polio hard to study?
- hardy: resistant to degradation
- dangerous. Cutter incident, humans are the only host.
what is one example of why polio is ~dangerous~ to study?
the Cutter incident
what happened in the Cutter incident?
Cutter was a lab that produced vaccines. Some batches of Salk’s polio vaccine contained live virus which led to tons of people being infected upon vaccination and 5 children died.
what happens in post polio syndrome?
motor neurons compensate for the motor neurons that were killed when the body was infected with polio
what eventually happens to the motor neurons that don’t die upon infection?
they die later because they’ve spent their lifetimes compensating for the missing neighboring motor neurons that died
who is most susceptible to polio infection?
children under 5
who is most susceptible to paralysis?
older children/teens and young adults
what puts people at risk for contracting polio? (2)
- poor water sanitation
- decreased vaccine rates
how to prevent polio? (one word)
vaccines
what vaccines are available for polio?
OPV and IPV
who developed the OPV? what does it stand for?
Sabin. Oral polio vaccine.
which antibodies respond when the OPV is administered?
IgG and IgA
why does OPV prevent the spread of polio?
IgA replicates in mucous membranes, neutralizes the virus in the mucous membranes so not only does it not spread through feces, but the vaccine spreads through feces instead
how many doses are required for OPV?
one
how many doses are required for IPV?
multiple
OPV: attenuated or inactivated?
attenuated
cons of OPV?
attenuated vaccine, meaning a strain can mutate to virulent form (very uncommon, 1/24 mil.)
who developed the IPV? what does it stand for?
Salk. Inactivated polio vaccine
which antibodies respond when the IPV is administered?
IgG
IPV: attenuated or inactivated?
inactivated
did the Cutter incident occur with the OPV or IPV?
Salk: IPV
List the 6 stages of a polio infection/life cycle:
- endocytosis
- release + protein synthesis
- replicase made
- replication of RNA
- translation packaging
- cell lysis to release viral particles
which surface protein does polio virus bind to?
host cell receptor CD155
