Pico Flashcards
Enteroviruses
Acid stable virion
common between June and November
Fever and rash in kids
URIS in kids and adults
Aseptic meningitis (more severe in adults compared to kids)
Rhinoviruses
Fomites-Hand-to-Eyes or aerosol transmission
NOT acid stable (degrades in GI tract)
100 serotypes
Upper respiratory
Most frequent cause of common cold
Hepatitis A Viruses
Acid stable virion (survive GI tract, can be spread via fecal-oral route)
Fecal-oral or contaminated food
Pharynx/intestine
Acute Hepatitis
Cases reduced from 100,000/yr to 10,000/yr post vaccine
Polioviruses
Acid stable virion (survive GI tract–> can be spread via fecal-oral route)
For every 100 with poliovirus in stool
- 90-95 asymptomatic
- 4-8 have minor illness (–URI, flue-like)
- 1-2 aseptic meningitis
- 0.1-1 paralytic disease
Polio can be eradicated because
o Only affects humans (no animal reservoirs)
o Effective, inexpensive vaccines
o Immunity is life-long
o There are no long-term carriers
o Virus can’t survive long outside the body
o Eradication=complete elimination to the point where vaccination is no longer needed (only happened with small pox)
WHO strategy for polio eradication
o Routine OPV immunization
o Enhanced surveillance
Mopping up immunization activities- door-to-door immunization of polio patient community
Pitfalls in Polio Eradication
individuals may persistently shed virus (rare); transmission of OPV vaccine strains following cessation of vaccination; vaccine strains revert to wildtype; reemergence of wildtype from other sources (frozen fecal samples, undetected sources in population, terrorists, etc)
IPV: Inactivated Polio Vaccine
o Killed, injected, no vaccine-assoicated disease
o Protective IgG
o Limited mucosal immunity, more expensive that OPV
o As of 2000, CDC recommends exclusive use of IPV
OPV=live attenuated polio
o Live attenuated; oral, inexpensive
o Systemic AND mucosal immunity
o Vaccine-associated poliomyelitis (VAPP) 1/500,000
Coxsackievirues
Acid stable virion
Coxsackievirus A can cause Hand-Foot and Mouth Disease highly infectious, usually resolves in 1 wk
Coxsackievirus A24 can cause hemorrhagic conjunctivitis
Coxsackievirus B in acute myocarditis and pericarditis
Coxsackievirus A
can cause Hand-Foot and Mouth Disease highly infectious, usually resolves in 1 wk
Coxsackievirus A24
can cause hemorrhagic conjunctivitis
Coxsackievirus B
in acute myocarditis and pericarditis
Echoviruses
Acid stable virion
Enteric, Cytopathic, Human, Orphan virus = ECHO (orphan=no disease association)
aseptic meningitis
Picornaviruses
Basics
small, nonenveloped, icosahedral viruses.
single-stranded, positive sense RNA genome
Are pico’s unique to people
No they like to live in everybody
Humans, apes and monkeys, pigs, cattle, mice, seals, shrimp, tortoises, birds and bees, and plants are some of the hosts infected by viruses in the Picornavirales order.
What are the group C Enteroviruses
Polioviruses
Coxsackieviruses
some Enteroviruses
RNA recombination occurs frequently among members of each species group
approaches to polio vaccines can eradicate the capsid genes of poliovirus; however, the remainder of polio genomes will survive indefinitely within ________
other group C enteroviruses.
What molecules of the virus & host define serotypes
Epitopes on capsid proteins recognized by antibodies that neutralize infectivity.
Most non polio virus circulating is
ECHO
Most non polio virus circulating is causing?
Aseptic Meningitis Encephalitis Paralysis (AFP) Respiratory Illness Myocarditis Hand-Foot-Mouth Disease
Picornaviruses, the Most Common Respiratory Virus Causing Infection among ______________?
Patients of All Ages Hospitalized with Acute Respiratory Illness
~25% of all patients……most frequent cause in all age groups.
When are seasonal epidemics of enterovirus disease in the US?
Summer Time
US common June –> November
Aseptic meningitis cases peak in late summer (August/September).
Enteroviruses most common etiologic agent.
Aseptic meningitis cases peak in late summer (August/September).
___________ most common etiologic agent.
Enteroviruses
Replication: (+)Strand RNA Viruses
Replication occurs exclusively in the cytoplasm.
Virions DO NOT contain replication proteins.
(+) RNA–> (-) RNA–> (+) RNA.
via Viral RNA-dependent RNA polymerase
Virion RNA serves three functions
Genome: packaged in virion.
Viral mRNA: translated into viral replication proteins.
Template RNA: copied into (-)strand RNA for replication.
Because of _____________, poliovirus can circulate unnoticed
inapparent infections
Poliovirus Pathogenesis
day 0= injest virus.
day 1-2= Infection of non-neural tissues
day 2-7 amplification
day 7-14: cross BBB. Retrograde Axonal Infection
Motor Neurons Killed–>AFP
(sensory neurons unaffected)
What kind of cell does polio kill
Motor Neurons Killed–>AFP
(sensory neurons unaffected)
Inactivated Poliovirus Vaccine (IPV)
Killed Wildtype Poliovirus
Injected
No Vaccine-Associated Disease
Protective Systemic Immunity (IgG)
Oral Poliovirus Vaccine (OPV)
Live-Attenuated Poliovirus Oral Administration Inexpensive Systemic AND MUCOSAL immunity Can actually cause polio- VAPP
who gets Vaccine-Associated Paralytic Poliomyelitis (VAPP)
OPV Vaccine Recipients (Infants, First Dose)
Contacts of OPV Recipients (Non-immune, First Exposure)
Immunocompromised (Recipients and Contacts)
