Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Inflamm Final > Neurotropic Viruses and Prions > Flashcards

Neurotropic Viruses and Prions Flashcards

1
Q

what are the three key cerebrovascular barriers that protect the brain and central nervous system?

A
  1. Blood-Meningeal Barrier (BMB)
  2. Blood-Brain Barrier (BBB)
  3. Blood–Cerebrospinal Fluid Barrier (BCSFB)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why is immune activity restricted in the CNS?

A
  1. Limited immune surveillance
  2. Low MHC class II expression
  3. Restricted entry of immune cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is IRIS (Immune Reconstitution Inflammatory Syndrome)?

A

immune activity rebounds too strongly and causes brain inflammation

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

what is a neurotropic virus?

A

a virus that has a preference for infecting nervous system tissues by targeting nerve cells, having an affinity for CNS or PNS and commonly associated with neurological diseases

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

what are two key properties that lead to neuropathology?

A

neuroinvasivness → The virus’s ability to enter the nervous system
neurovirulence → The virus’s ability to cause disease once it’s in the CNS/PNS

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

what are the ways a neurotropic virus can present in the body?

A
  1. Encephalitis→ Inflammation of the brain
  2. Meningitis→ Inflammation of the meninges
  3. Myelitis→ Inflammation of the spinal cord
  4. Encephalopathy→ Functional damage to the brain
  5. Latent Infection→ The virus stays dormant in nerve cells for long periods
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the initial entry sites of viral infections?

A

enter the body through GI tract (Enterovirus), skin (Arboviruses, HIV), urogenital tract (HSV, HIV), or respiratory tract (Mumps) and replicate in local or regional tissues first

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

what are the two ways viral infections spread to the CNS?

A
  1. Hematogenous spread
  2. axonal transport
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Hematogenous spread

A

virus travels in the blood (viremia), passes through blood vessel walls (extravasation), and enters the brain via the choroid plexus or endothelial cells

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

Direct BBB crossing

A

virus crosses directly into the brain tissue
* (WNV, EEE)

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

Trojan Horse Mechanism

A

Virus hides inside immune cells like monocytes/macrophages, which then cross the BBB
* (HIV, CMV)

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

Retrograde axonal transport

A

Virus travels from body tissues back to the CNS via dorsal root ganglia or motor neurons
* (HSV/VZV or rabies).

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

Anterograde axonal Transport

A

Virus moves from peripheral nerve endings toward the brain via the olfactory nerve
*(VSV, HSV Influenza)

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

who does viral encephalitis/meningitis mainly effect?

A

new borns, children, elderly and immunocompromised people

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

what are the viruses that are common causers of Acute Meningitis?

A
  • Enteroviruses: Most frequent cause, especially in children
  • Arboviruses: Mosquito-borne viruses like West Nile virus
  • HIV: Can cause meningitis early in infection
  • HSV-2: Genital herpes virus, known to cause meningitis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the viruses that are common causers of Acute Encephalitis?

A
  • Arboviruses
  • Enteroviruses
  • HSV-1: Leading cause of sporadic fatal encephalitis in the U.S.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is the classic triad of viral CNS disease symptoms?

A

fever
headache
altered mentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

when diagnosing a viral CNS infection what would an altered mental status point towards?

A

encephalitis
*meningitis would have no altered mental status

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

if altered mental status or neurological deficits are present in a patient, what is the next step?

A

brain imaging (CT or MRI) is done before lumbar puncture (to avoid herniation risk)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is key to diagnosing viral CNS infections?

A

lumbar puncture to determine if viral or bacterial
***PCR (Nucleic acid detection): Most accurate and sensitive test, gram stain is negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

if the lumbar puncture points towards viral infection what testing is done next?

A
  • First-Tier Viral Testing (CSF): PCR for enterovirus or IgM for west nile
  • Second and Third Tier Testing (if 1st is neg): PCR based on exposures and symptoms
22
Q

what is the most common cause of viral meningitis?

A

non-polio enteroviruses

23
Q

what are characteristics of viral meningitis caused by non-polio enteroviruses?

A
  • spreads through fecal-oral
  • typically asymptomatic or mild
  • 75% of meningitis cases
    (Coxsackie viruses, Echoviruses, EVs)
24
Q

what is herpes simplex virus type 1 and 2 most commonly associated with?

A

HSV-1: encephalitis
HSV-2: meningitis

25
what are characteristics of encephalitis caused by HSV-1?
- 10-20% of all cases - 70% mortality if left untreated
26
what are characteristics of meningitis caused by HSV-2?
classically associated with aseptic meningitis - in newborns both viruses cause menigoencephalitis - 85% infection at time of birth from genital track
27
what is the major cause of viral myelitis?
polio enterovirus
28
one in every 200 polio cases, the virus
destroys nerve cells leading to irreversible paralysis usually in the legs
29
what are arboviruses and what are some examples?
viruses transmitted to humans by mosquitos or ticks - Togaviruses: flaviviruses and alpha-viruses - Reoviruses - Bunyaviruses
30
West Nile Virus (Flavivirus)
80% asymptomatic neuroinvasive disease transmitted through mosquito bites
31
St Louis Encephalitis Virus (Alphavirus)
third most common cause of viral encephalitis where 25% of patients have neurological sequelae
32
what are the less common causes for viral meningitis and encephalitis?
- Lymphocytic Choriomenigitis Virus - Mumps - Measles - Human herpesvirus 6 - EBV - Rabies
33
What is a Prion?
an infectious abnormal, misfolded protein, not a virus or bacteria where the protein itself is the disease-causing agent — no DNA or RNA involved
34
how are prions similar to viruses?
- small - filterable - need host cell - no machinery for energy generation or protein synthesis
35
how are prions different from viruses?
- no detectable virions in infected tissue - no detectable virions in purified infectious material - if nucleic acid is present, it is very small - very resistant to denaturation
36
what are prion diseases?
spongiform encephalopathies because they cause the brain to look “spongy” under the microscope due to neuronal degeneration
37
what are spontaneous (sporadic) prion diseases and give an example?
Most common type that happens randomly, without a known cause or family history,causing 85% of cases in older patients *Sporadic Creutzfeldt-Jakob Disease (sCJD)
38
what are genetic (inherited) prion diseases and give examples?
disease caused by mutations in the PRNP gene, which makes the prion protein usually inherited from family members and causes 10-15% of cases * Genetic CJD (gCJD or fCJD), GSS (Gerstmann-Sträussler-Scheinker disease), FFI (Fatal Familial Insomnia)
39
what are acquired (infectious) prion diseases and give examples
disease caused by spread through exposure to infected tissues causing <1% of all cases (rare) in younger patients * Iatrogenic CJD (iCJD): from medical procedures, Variant CJD (vCJD): linked to “mad cow disease”, Kuru: cannibalism in New Guinea
40
what are the prion disease of animals?
- Bovine Spongiform Encephalopathy (BSE) (cows) - Scrapie (sheep, goats) - other (squirrels, mink) - Chronic wasting disease (deer and elk)
41
Mad Cow Disease (BSE)
- bovine spongiform encephalopathy - transmitted from cattle to humans by infected beef - highest concentration of prions in brain and nervous system
42
how are prions transmitted to humans in vCJD?
- beef or other contaminated food products from infected cattle - food products from other infected animals (sheep, squirrels, etc.) - human cornea transplants (3)
43
how are prions transmitted in humans for iCJD?
- human dura mater transplants (>110) - improperly sterilized neurosurgery instruments (4)/electrodes (2) - human cadaver growth hormone and gonadotropin (>130)
44
what are the symptoms of Kuru?
uncontrollable laughter, headaches, ataxia, joint pain, death
45
what are the normal characteristics of the Prion Protein (PrPC)?
- alpha helix conformation - encoded by the human genome - expressed in most tissues - heavily glycosylated - tends to aggregate yielding rod shaped polymers
46
what is the altered conformation of the prion protein (PrPSC) associated with disease?
- folds into a form with extensive beta-pleated sheets
47
prions are extremely resistant to
inactivation
48
how do prion proteins spread in the brain?
through a chain reaction where PrPˢᶜ (scrapie form) is the mutant/infectious prion protein that causes normal proteins (PrPᶜ) to misfold into more PrPˢᶜ
49
how are prions inactivated?
1M sodium hydroxide followed by: - autoclaving at higher temps for longer times - higher concentrations of denaturants (4M guanidine isothiocyanate) - material for decontamination should be considered (instrument surface decontamination, porous surfaces, tissue samples)
50
what is the diagnostic criteria for probable sporadic CJD?
rapidly progressive cognitive impairment and two neurological signs plus one biomarker criterion or progressive neuropsychiatric syndrome and positive RT-QulC
51
what is the immune response for prions?
none
52
what does genetic testing for prions reveal?
blood test for PrP mutations will reveal inherited mutation (fCJD) but will not detect spontaneous mutation in somatic tissues

Inflamm Final (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions