Flashcards in Poliovirus Deck (24)
Poliovirus is a member of what family?
What other viruses are picornaviridae?
common cold and hepatitis
What is the genus of poliovirus?
Enterovirus- which means it spreads via fecal/oral route and replicates in the GI tract
nonenveloped icosahedral capsule
WHat major symptoms does polio cause
flaccid paralysis called poliomyelitis
How many annual cases of polio worldwide
less than 1,000
Polio has been absent from US since>
Absent from western hemisphere since 1994
Humans only...this combined with the few number of serotypes makes it easy to vaccinate agianst
Initial replication of poliovirus occurs where?
Lymphoid tissue of pharynx and gut. So the virus is present in the throat and the feces
Virus spreads to CNS and does what
destroys motor neurons
90% of polio infections are...
Three types of disease caused by poliovirus
- 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
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
increased weakening of muscles later in life
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
Polio is best inactivated with?
formaldehyde or chlorine
Poliovirus is resisitant to?
ethanol and detergents
Us recommends use of what vaccine
inactivated vaccine called
Advantage is that the inactivation prevents reversion to virulence
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
DO not use Salk IPV if allergic to
neomycin, streptomycin, or polymyxin B
Advantages to Sabin OPV
cheap, oral admin, protects against paralysis and spread