L82

Question 1

Are picorna viruses RNA or DNA?

Answer 1

“I went to a retro toga party, drank flavored Coronas, and ate hippy Cali pickles”

Pickles = picorna = +ssRNA

Question 2

Mnemonic for picorna viruses

Answer 2

PERCH
Polio
Echo
Rhino
Coxsackie 
Hep A (acute viral hepatitis)

Question 3

Picorna

• Enveloped? –> How released from cells?
• Where replicate?

Answer 3

Naked - released by lysis

RNA - replicate in cytoplasm

Question 4

Enterovirus is an umbrella term - how so?

Answer 4

Enteroviruses split into 2 categories

• Polio
• Non-polio = coxsackie & echo viruses & enteroviruses

Question 5

Enterovirus transmission

Answer 5

P2P via fecal-oral
Respiratory
AKA low inoculum needed to create disease

Question 6

Enterovirus season

Answer 6

Summer –> fall

Question 7

Enterovirus pathogenesis

Answer 7

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

Question 8

Why is the 1ary viremia from enteroviruses not generally clinically significant?

Answer 8

1ary viremia = minor

Often controlled by Ab

Question 9

What is distinguishable about the enteroviruses from other picorna viruses?

Answer 9

Resist harsh environments - low pH, detergents, sewage

Allows for oral-fecal transmission!!

Question 10

When would you see a 2ary viremia from enteroviruses?

Answer 10

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

Question 11

Is damage from enteroviruses due to the bug or immune response?

Answer 11

Mostly bug - lysis release = cell damage

Host immune response causes myocarditis & rash specifically

Question 12

What is polio’s tissue tropism? (aka where does it go during 1ary viremia?)

Answer 12

Brain
Meninges
Ant horn spinal cord

Question 13

What kind of paralysis does polio cause?

Answer 13

Flaccid
Asymmetric 
Intact sensory neurons 
Proximal before distal
Lower before upper extremities

Question 14

Why is polio described as biphasic?

Answer 14

1st = minor illness = fever, muscle pain, lose deep tendon reflexes
2nd = SUDDEN onset paralysis
Max weakness within 5 days

Question 15

What disease is caused by polio’s tropism for the meninges?

Answer 15

Aseptic meningitis

Question 16

Diagnose meningitis

Answer 16

Clinical + culture ASAP

Question 17

What is the difference between the oral and the injected polio vaccines?

Answer 17

Oral = live, don't us in US b/c can mutate to cause disease
Injected = inactivated, lifelong immunity

Question 18

Where is polio still a problem in the world?

Answer 18

Pakistan

Afghanistan

Question 19

Why are we switching from a trivalent –> bivalent injectable vaccine?

Answer 19

Remove polio serotype 2 - most likely to reactivate to active disease + not seen in wild anymore
Plus vaccines with fewer strains are more immunogenic

Question 20

What is herpangina/stomatitis? What virus causes this?

Answer 20

Enanthem = painful mouth blisters
+ fever
Coxsackie A

Question 21

What is hand-foot-mouth disease? What viruses cause this?

Answer 21

Blisters in mouth, hands, feet
Sometimes on butt/groin
\+ fever
Cox A & B
Enterovirus 71

Question 22

What is the difference between coxsackie groups A & B?

Answer 22

A: does not grow well in culture
B: grows well

Question 23

What 3 CNS infections can non-polio enteroviruses cause? Name the most likely viral cause of each.

Answer 23

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

Question 24

What on a CSF culture makes you think aseptic meningitis?

Answer 24

Normal glucose & proteins
Negative gram stain… duh
Hugh white count

Question 25

What is pleurodynia? What virus causes this?

Answer 25

= Inflam of chest & ab wall muscles (skeletal muscle)
“I have sharp pain in my chest/ab”
Cox B

Question 26

What is myositis? What is the viral cause?

Answer 26

Generalized muscle pain, fever, chills
+ peeing muscle protein (myoglobin)
+ ↑muscle enzymes
Cox B

Question 27

How can non-polio enteroviruses affect the heart?

Answer 27

Myocarditis

Question 28

How can non-polio enteroviruses affect the eyes? Explain disease + most common viral cause.

Answer 28

Acute hemorrhagic conjunctivitis
- SUPER contagious via tears/touching
- Blood shot eyes + pain
Cox A & enterovirus 70

Question 29

If a neonate presents with a non-polio enterovirus infection, what are the symptoms? How did this baby get sick? Viral cause.

Answer 29

Vertical transmitted from mom
Sick in 1st week of life
Looks like SEPSIS: myocarditis, encephalitis, hepatitis, pna
ECHO or Cox B

Question 30

Diagnose non-polio enterovirus infection

Answer 30

Culture from invasive infection site
Serum Abs
PCR

Question 31

Treat non-polio enterovirus infections

Answer 31

All experimental
Myocarditis = IVIG
Others = oxadiazoles
- Block viral attachment and uncoating

Question 32

What meds do you NEVER give for enterovirus infections because outcomes are worse?

Answer 32

Steroids!!!