L82 Flashcards
Are picorna viruses RNA or DNA?
“I went to a retro toga party, drank flavored Coronas, and ate hippy Cali pickles”
Pickles = picorna = +ssRNA
Mnemonic for picorna viruses
PERCH Polio Echo Rhino Coxsackie Hep A (acute viral hepatitis)
Picorna
- Enveloped? –> How released from cells?
- Where replicate?
Naked - released by lysis
RNA - replicate in cytoplasm
Enterovirus is an umbrella term - how so?
Enteroviruses split into 2 categories
- Polio
- Non-polio = coxsackie & echo viruses & enteroviruses
Enterovirus transmission
P2P via fecal-oral
Respiratory
AKA low inoculum needed to create disease
Enterovirus season
Summer –> fall
Enterovirus pathogenesis
Ingest particles = fecal-oral
Inhale particles = resp droplets
Replicate in mouth/throat or intestines –> invade –> LN –> 1ary viremia minor viremia –> tropic organs
If est infection in tropic organs, give rise to 2ary viremia
Why is the 1ary viremia from enteroviruses not generally clinically significant?
1ary viremia = minor
Often controlled by Ab
What is distinguishable about the enteroviruses from other picorna viruses?
Resist harsh environments - low pH, detergents, sewage
Allows for oral-fecal transmission!!
When would you see a 2ary viremia from enteroviruses?
If disease est sizable replication and infection in tropic organs –> leave these organs back in circulation = 2ary viremia
Means Abs were not present or failed to contain 1ary viremia
Is damage from enteroviruses due to the bug or immune response?
Mostly bug - lysis release = cell damage
Host immune response causes myocarditis & rash specifically
What is polio’s tissue tropism? (aka where does it go during 1ary viremia?)
Brain
Meninges
Ant horn spinal cord
What kind of paralysis does polio cause?
Flaccid Asymmetric Intact sensory neurons Proximal before distal Lower before upper extremities
Why is polio described as biphasic?
1st = minor illness = fever, muscle pain, lose deep tendon reflexes
2nd = SUDDEN onset paralysis
Max weakness within 5 days
What disease is caused by polio’s tropism for the meninges?
Aseptic meningitis
Diagnose meningitis
Clinical + culture ASAP
What is the difference between the oral and the injected polio vaccines?
Oral = live, don't us in US b/c can mutate to cause disease Injected = inactivated, lifelong immunity
Where is polio still a problem in the world?
Pakistan
Afghanistan
Why are we switching from a trivalent –> bivalent injectable vaccine?
Remove polio serotype 2 - most likely to reactivate to active disease + not seen in wild anymore
Plus vaccines with fewer strains are more immunogenic
What is herpangina/stomatitis? What virus causes this?
Enanthem = painful mouth blisters
+ fever
Coxsackie A
What is hand-foot-mouth disease? What viruses cause this?
Blisters in mouth, hands, feet Sometimes on butt/groin \+ fever Cox A & B Enterovirus 71
What is the difference between coxsackie groups A & B?
A: does not grow well in culture
B: grows well
What 3 CNS infections can non-polio enteroviruses cause? Name the most likely viral cause of each.
- Aseptic meningitis - all of the viruses can do this, and overall this group of viruses is the most common reason for aseptic meningitis across the board
- Encephalitis - Cox A (Entero 71 outbreak)
- Polio-myelitis-like illness : N/A
Guillain-Barre or acute transverse myelitis possible
What on a CSF culture makes you think aseptic meningitis?
Normal glucose & proteins
Negative gram stain… duh
Hugh white count
