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Jonathan's Neuroscience > CNS Virus > Flashcards

Flashcards in CNS Virus Deck (35):
1

Define Neurotropic

capable of replicating in nerve cells

2

Define neuroinvasive

capable of entering or infecting the CNS

3

Define neurovirulent

capable of causing disease within the nervous system

4

What's myelitis?

infection of the spinal cord

5

What are the most common causes of viral meningitis?

herpes simplex virus
rabiesvirus
arbovirus
enteroviruses

6

What's the pathophysiology of postinfectious encephalomyelitis

inflammation and demyelination due to possible autoimmune damage

7

What's the pathophysiology of Guillain-Barre syndrome?

post-infectious (viral) inflammation and demyelination leading to partial or total paralysis

8

T/F Most people can recover completely from guillain barre

True, 75% of people recover within weeks

9

What are the presenting symptoms of Reye's syndrome

cerebral oedema, and a lot of swelling but not inflammation

10

what's Reye's syndrome caused by

post-infection with influenza or chickenpox

11

T/F Reye's syndrome may be associated with administration of paracetamol to treat fever

False, it is linked to aspirin administration

12

What's the pathophysiology of chronic demyelinating disease?

A late sequel to measles, which the antibody selects a specific strain of measles to infect CNS neurons, causing very slow onset sub-acute sclerosing panencephalitis

13

How does virus get into the CNS?

infect PNS neuron
enter directly via blood stream, commonly the choroid plexus
via olfactory bulb

14

Why can't we our immune system get rid of the virus inside PNS neurons

nerve cells don't express MHCI to activate CD8 T cells', and the intracellular pathogen cannot be cleared

15

Where does the replication of virus in nerves occur?

at the soma of nerve, where virus can utilise host machinery

16

How does virus cause damage in the CNS?

direct killing of neurons
replicate in non-neuronal cells to cause demyelination
induce inflammation to allow entry of lymphocyte via BBB

17

T/F Rabiesvirus must grow inside a nerve cell

True

18

describe the shape and virus type of rabiesvirus

bullet shaped with helical capsid and envelop
It's a -ve stranded RNA virus

19

How does a virus exit the cell if it has an envelop?

budding

20

T/F Rabiesvirus actively evades the immune system

False, it displays glycoprotein on the cell surface and can be targeted by antibody

21

What are the symptoms associated with rabies

aggression
thirst but unable to drink water

22

Why does rabiesvirus cause muscle spasm upon attempt to drink water (what's the logic of it)

Rabies spread via the saliva, and water will dilute the viral load

23

Describe the life cycle of rabiesvirus

entry via a site of penetrated skin
contaminated saliva infect muscle cell
eventually reaches a PNS nerve
works its way up to the CNS
invades the salivary gland to spread

24

T/F Vaccines are only useful prophylactically

False, there is a window to use vaccine against rabies virus after being infected (before virus enters the CNS)

25

Describe the shape and type for alpha herpesvirus

large envelope, icosahedral shape
linear dsDNA genome

26

What's the primary infection site of herpes

mouth or the lip

27

How does herpes infect body's organs

hide in PNS nerve cells or spread as viremia to different organs. They can then spread to the CNS

28

T/F Proteins are actively produced in latent herpes infection

False, there is no structural gene expression

29

What keeps the herpes virus in the latent stage

CD8 T cells, hence virus can reactivate when immune system is compromised

30

What is the reactivation phage called in herpes

Shingles, painful blisters that follow dermatome distribution

31

T/F Poliovirus must grow in a nerve cell as part of the life cycle

false, they just accidentally get into nerve cells

32

describe the shape and type of poliovirus

+ve stranded RNA virus with icosahedral capsid
no envelope

33

How does poliovirus cause damage?

it's cytocidal, killing cells in which they replicate

34

Where does poliovirus typically replicate in the CNS?

anterior horn cells because there is a receptor for polio

35

What kind of CNS symptoms can polio cause?

acute paralysis