Viruses affecting the CNS Flashcards Preview

Hugh's MD1 Neuro > Viruses affecting the CNS > Flashcards

Flashcards in Viruses affecting the CNS Deck (42):
1

Under what circumstances do lymphocytes cross the BBB?

During inflammation of the CNS

2

At what point does HIV become neurovirulent?

Once immunodificiency presents

2

Is it more common for alpha herpes viruses to travel to the CNS via the blood or through peripheral nerves?

Peripheral nerves

3

How does the rabies virus interact with the immune system?

It doesn't try to hide, rather its glycoprotein is displayed on the cell surface

4

What is Guillain-Barre syndrome?

An acute inflammatory demyelinating disease following viral infection - commonly EBV, CMV, and HIV

4

T/F Viral replication occurs at the synapses in the nerve cells so they can quickly infect other cells

False, they replicate in the cell body as they require the protein synthesis machinery

4

What type of virus is rabies?

-sense RNA virus

5

Where is a common location for viral entry into the parenchyma of the CNS?

The choroid plexus

5

How does poliovirus get into the spinal cord?

Gut > regional lymph nodes > blood > spinal cord 

6

How do young children with HSV 1 present?

Gingivostomatitis (cold sores)

7

In which is the virus still present, postinfectious encephalomyelitis or postinfectious encephalitis.

Postinfectious encephalitis

8

What type of virus is poliovirus?

+RNA with isosahedral capsid and no envelope

9

Does Guillain-Barre syndrome require an active infection?

No, as show by the outbreak that followed a vaccination program for influenza that used an inactivated virus

9

T/F Growth in nerve cells is obligatory part of the lifecycle or alphaherpes viruses and poliovirus

False, not for poliovirus

10

How does rabies virus get to the salivary glands?

Travels via the peripheral nerves and brain and down into them

12

What is the case fatality rate of HSV encephalitis?

70%

13

In which structure do HSV typically establish a latent infection?

Sensory nerve ganglia of the trigeminal or sacral nerve

14

What is Reye's syndrome?

Post-infectious cerebral oedema in children. Influenza or chicken pox

16

What are the most common causes of viral encephalitis?

HSV 1 and 2

Rabies virus

Arboviruses

Enteroviruses

17

In what form is the HSV genome maintained in latent infections?

Episome coated with histones

19

What is secondary encephalitis (aka post-infectious encephalitis)

Secondary viral infection of the CNS, usually via the blood

19

True or false, rabies replicates in the salivary glands only

False, it also replicates in the muscle adjacent to its entry point

21

What is so problematic about viruses traveling in peripheral nerves?

They're protected from attack by CTLs 

22

How does varicella-zoster virus enter the body?

Respiratory transmission

24

What is the sequelae of viral infection of oligodendrocytes?

Demyelination

24

In which cells does poliovirus infect in that leads to paralysis?

Anterior horn cells in the spinal cord

25

Why aren't peripheral nerves targeted by CTLs?

They don't MHC class I

26

What are neuroinvasive viruses capable of?

Entering or infecting the CNS

27

What immune mechanism may be responsible for keeping the HSV genome in a latent state?

CD8+ T cells

28

Why is the fear of water in rabies?

Evolutionary adaptation of the virus to avoid dilution of the virus in the saliva

29

What are neurotropic viruses?

Viruses capable of replicating in nerve cells

31

Describe HSV 1 and 2 in terms of neuroinvasiveness and neurovirulence

Low neuroinvasiveness

High neurovirulence

32

What is myelitis?

An infection of the spinal cord

33

Are alpha herpesviruses non-enveloped or enveloped?

Enveloped

34

How is HSV 1 transmitted?

Via saliva

35

What are neurovirulent cells capable of?

Causing disease within the nervous system

36

What are two stategies of entering the CNS used by viruses?

Traveling up peripheral nerves

Crossing the BBB

38

Which virus causes a mild encephalitis?

Mumps virus

39

At what point during varicella-zoster infection does virus enter peripheral nerves?

After entering rashes

40

What is the mechanism of damage postulated to cause postinfectious encephalomyelitis?

Autoimmune demyelination

41

Does rabies infect neurones or oligodendrocytes?

Neurones, it's highly neuroinvasive and neurovirulent

42

Coronavirus and herpes simplex virus share this route of entry to the CNS, what is it?

Via the olfactory bulbs