Viruses Flashcards

1
Q

Why are viruses important in oral health

A

Cause infection in oral cavity
Easily spread
Hard to treat

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

Draw the structure of a virus

A

4 parts - capsid ( protein case )
- nucleic acid genome (DNA OR RNA -not both )
- envelope (lipid membrane - helps adhere to host cell)-NOT ALL VIRUSES HAVE

Lack organelles /enzymes

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

What is special regarding virus replication

A

Cannot reproduce themselves or use binary fusion
Must use another host cell to replicate

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

Name 5 steps in virus replication

A
  1. Recognise a host cell receptor and Attachment to host cell -
  2. Absorbing into cell - 3 ways
    - fusing of virus and host cell membrane
    - endocytosis of virus
    - diffusion entire virus across the host cell
    membrane
  3. Nucleic acid replication - particles reach cytoplasm capsid sheds off and genome uses the host cells “machinery “to replicate viral genome into viral proteins ( via transcription/translation )
  4. Viral assembly - new viral proteins/genomes assemble into new viral particles
  5. Virus release - 3 mechanisms
    - cell lysis -releases virus OR
    if enveloped viruses -bud or exocytosis where the protein inserts itself into the host membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is viral latency

A

After the primary infection the virus can lay “dormant” in a ganglion then become reactivated and cause active secondary infection

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

Give an example of a mouth virus and how it presents on its primary then secondary infection once its been latent

A

Herpes simplex virus type 1(most common mouth viral infection )
see. Primary stage - gingivostomatitis - asymptomatic or ulcers then it can …

Moves to trigeminal ganglion and lays in latent stage

Reactivation by stress/ sunlight /illness/ Trauma area etc

Reactivates - secondary HSV - cold sore - travels down peripheral nerve of trigeminal Nerve and causes ulceration on mucocutaneous area lip

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

What can cause reactivation of secondary virus infection in latent state

A

Stress
Sunlight
menstruation
illness
Trauma to the area

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

Name 2 oral viruses and their symptoms /complications

A

1.Herpes simplex type 1 virus - most common in mouth
gingivostomatitis - asymptomatic or ulcers
lays latent and secondary infection =cold sores
saliva transmitted

2.Epstein Barr virus ( ebv)- glandular fever
pharyngeal inflammation /tonsil large
saliva transmitted
children maybe subclinical

EBV CAN CAUSE BURKITTS lymphoma

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

How can you prevent virus infections

A

PPE/appropriate hygiene ( IMPT in oral health)
Vaccination - complicated
Antiviral medications

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

Name 2 antiviral medications and how they work

A

Amantadine ( influenza) - inhibits viral uncoating so genome not able be replicated

Acyclovir - inhibits DNA synthase - stops replication

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

Why is forming an antiviral difficult

A

high mutation rates

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

3 reasons Why a viral vaccination treatment is difficult

A

Antigenic shift
Antigenic drift
Low vaccination rates

All lead to increase in virus changes/mutations so vaccination then not effective )

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

What is antigenic shift

A

2 or more strains virus combine - so sudden genome changes causing new subtypes and infect more virulently or other organisms

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

What is antigenic drift

A

slow small mutations that accumulate overtime so eventually a new virus subtype emerges - vaccines then don’t work

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

Why do antibiotics not kill viruses

A

No peptidoglycan cell walls, no ribosomes, not replicate their own DNA
Need host cells to replicate not replicate by themselves

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

How are viruses replication different to bacterial cells

A

Need a host cell to replicate ( cannot replicate by themselves )
No binary fission