Flashcards in Poliovirus Deck (24)
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1
Poliovirus is a member of what family?
Picornaviridae
2
What other viruses are picornaviridae?
common cold and hepatitis
3
What is the genus of poliovirus?
Enterovirus- which means it spreads via fecal/oral route and replicates in the GI tract
4
poliovirus morphology>
nonenveloped icosahedral capsule
5
WHat major symptoms does polio cause
flaccid paralysis called poliomyelitis
6
How many annual cases of polio worldwide
less than 1,000
7
Polio has been absent from US since>
1977
Absent from western hemisphere since 1994
8
Polio reservoirs?
Humans only...this combined with the few number of serotypes makes it easy to vaccinate agianst
9
Initial replication of poliovirus occurs where?
Lymphoid tissue of pharynx and gut. So the virus is present in the throat and the feces
10
Virus spreads to CNS and does what
destroys motor neurons
11
90% of polio infections are...
subclinical
12
Three types of disease caused by poliovirus
KNOW
- Abortive poliomyelitis- mild illness
- Aseptic meningitis- only 1-2% of those infected
- Paralytic poliomyelitis- risk increases with age, can affect just about any musculature, any paralysis after 6 months is permanent
13
Importance of secretory IgA immune response?
- Secreted by the gut, neutralizes the virus before it can be shed and thus can prevent spread of virus
14
Post-polio syndrome
increased weakening of muscles later in life
15
polio diagnosis
specimen collection from stool, rectal swabs, throat swabs, etc...
- neutralization assays are performed to confirm poilio
- vaccine strains distinguished from wild strains using specific antibodies
16
Polio is best inactivated with?
formaldehyde or chlorine
17
Poliovirus is resisitant to?
ethanol and detergents
18
Us recommends use of what vaccine
inactivated
19
inactivated vaccine called
Salk IPV
Advantage is that the inactivation prevents reversion to virulence
20
Disadvantages of the Salk IPV
- Takes four subcutaneous injections
- Protects against paralysis but not the spread of wild virus because soince it is subcu, you get a good IgG but no IgA
21
DO not use Salk IPV if allergic to
neomycin, streptomycin, or polymyxin B
22
Oral vaccine
Sabin opv
23
Advantages to Sabin OPV
cheap, oral admin, protects against paralysis and spread
24
