Microbiology - Enteric viruses I & II - Rebecca Greenblatt Flashcards

1
Q

Reoviruses have a segmented genome, which has what mode of gaining genetic diversity?

A

Reassortment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Transmission: Rotavirus (reovirus)

A

fecal-oral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Orthoreoviruses cause:

A

Mild GI symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Rotavirus causes severe:

A

dehydration, even though diarrhea is self-limited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What cells does rotavirus act on?

A

The cells of the small intestinal villi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does rotavirus have that acts like an enterotoxin?

A

NSP4 - rotavirus nonstructural protein 4 - interferes with sodium transport pumps - profuse watery diarrhea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Phylogeny: Rotavirus

A

ds RNA virus
+ sense
icosahedral
naked

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Phylogeny: Norovirus

A

ss RNA virus
- sense
icosahedral
naked

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Transmission: Norwalk virus (norovirus)

A

fecal-oral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

IU: Norwalk virus

A

low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

IU: Rotavirus

A

high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pathogenesis: Norovirus

A

Infection damages microvilli in small intestine → malabsorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Vomiting is more common in what enterovirus?

A

Norovirus - slows gastric emptying as comparing with rotavirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is primary viremia?

A

Successful virus travels in blood to seed replication site(s). LOW LEVELS in blood.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is secondary viremia?

A

New virus travels from replication site(s) to shedding site(s). HIGHER LEVELS in blood.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Phylogeny: Picornaviruses ie Poliovirus, Hep A, Coxsackievirus

A
Small
naked
icosahedral
\+ sense 
ss RNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Coxsackie A causes:

A

herpangina, hand-foot-and-mouth disease, acute hemorrhagic conjunctivitis

18
Q

Coxsackie B causes:

A

myocarditis
pleurodynia
meningitis

19
Q

Site of replication: Enteroviruses and Picornaviruses

A

All replicate in gut

20
Q

T/F: Poliovirus is human-restricted.

A

True

21
Q

How does poliovirus enter/infect epithelial/lymphoid cells in the gut lining?

A

CD155 receptor - found in gut AND cns gray matter cells

then spreads to the blood stream and regional lymph nodes

22
Q

How does nerve death occur in poliovirus?

A

Nerve death results both from lytic virus replication and overenthusiastic
immune response

23
Q

Viruses that produce polyproteins are vulnerable to what class of drugs?

A

Protease inhibitors

24
Q

Where is the location of acute poliomyelitis infection?

A

Infection of the anterior horn motor neurons of the spinal cord (muscle symptoms) and brain stem (respiratory symptoms)

Flaccid asymmetric weakness and muscle atrophy due to loss of motor neurons and denervation of their associated skeletal muscles

Of acute poliovirus infections, 1-2% result in neurologic symptoms.

25
Q

Transmission: Poliovirus

A

Fecal-oral

26
Q

Risk factors: paralytic poliomyelitis

A

young age, advanced age, recent hard exercise, tonsillectomy, pregnancy, immunosuppression

27
Q

________ can cause herpangina & has
been associated with severe complications. Fatalities, mostly in infants aged 6-11 months, have been reported.

A

Enterovirus 71

28
Q

Most common cause of herpangina:

A

Coxsackie A

Enterovirus - picornavirus

29
Q

Symptoms of herpangina:

A

Acute febrile illness

Small vesicular or ulcerative lesions on the posterior oropharyngeal structures

Typically occurs during the summer

Frequently in children, also young adults

Coxsackie A

30
Q

What viruses are primarily resonsible for acute hemorrhagic conjunctivitis?

A

Coxsackie group A24 (CA24) and enterovirus E70 (EV70)

31
Q

Why should the use of topical steroids be avoided in the treatment of acute hemorrhagic conjunctivitis?

A

Treatment with topical steroids should be avoided : risk of microbial superinfection of the cornea

32
Q

Viral myocarditis is most commonly caused by:

A

Adenovirus;
Enterovirus

Coxsackie B - one of the more severe presentations

33
Q

T/F: In viral myocarditis, CK-MB and Troponin I may be elevated.

A

True

34
Q

What is pleurodynia?

A

Pleurodynia (ploor-uh-din-ee-uh) (“Devil’s Grip”) is an uncommon complication of infection by coxsackievirus B or a few others

Sudden occurrence of lancinating chest pain attacks
Fever
Malaise
Headache

35
Q

What is the anatomic structure targeted by pleurodynia?

A

The striated muscle is the actual anatomic structure targeted by the coxsackievirus B and is responsible for the attacks of severe chest pain.

36
Q

Transmission: Coxackie B

A

Fecal-oral

37
Q

What physical exam finding points in the direction of pleurodynia/Coxsackie B infection?

A

Pleural/friction rub on lung exam

38
Q

When is pleurodynia life-threatening?

A

Infants

39
Q

In the developed world, >85% of aseptic/viral meningitis is caused by:

A

Enteroviruses

40
Q

Very young children with aseptic meningitis can present with what unique symptoms?

A

Fever w/ cold hands and feet;
Fretful, dislike of being handled,
pale, blotchy skin;
blank staring/unresponsive

41
Q

Enteroviruses and HSV can cause _______ in infants

A

septic shock

42
Q

Ospithotonic positioning may be a sign of _______ or may be seen in an infant who is attempting to compensate for airway edema or stridor.

A

meningitis