Flashcards in L82 Deck (32):
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
Hep A (acute viral hepatitis)
- 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
- Non-polio = coxsackie & echo viruses & enteroviruses
P2P via fecal-oral
AKA low inoculum needed to create disease
Summer --> fall
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?)
**Ant horn spinal cord**
What kind of paralysis does polio cause?
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?
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?
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
What is hand-foot-mouth disease? What viruses cause this?
Blisters in mouth, hands, feet
Sometimes on butt/groin
Cox A & B
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.
1. 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
2. Encephalitis - Cox A (Entero 71 outbreak)
3. 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
What is pleurodynia? What virus causes this?
= Inflam of chest & ab wall muscles (skeletal muscle)
"I have sharp pain in my chest/ab"
What is myositis? What is the viral cause?
Generalized muscle pain, fever, chills
+ peeing muscle protein (myoglobin)
+ ↑muscle enzymes
How can non-polio enteroviruses affect the heart?
How can non-polio enteroviruses affect the eyes? Explain disease + most common viral cause.
Acute hemorrhagic conjunctivitis
- SUPER contagious via tears/touching
- Blood shot eyes + pain
Cox A & enterovirus 70
If a neonate presents with a non-polio enterovirus infection, what are the symptoms? How did this baby get sick? Viral cause.
Vertical transmitted from mom
Sick in 1st week of life
Looks like SEPSIS: myocarditis, encephalitis, hepatitis, pna
ECHO or Cox B
Diagnose non-polio enterovirus infection
Culture from invasive infection site
Treat non-polio enterovirus infections
Myocarditis = IVIG
Others = oxadiazoles
- Block viral attachment and uncoating