Viruses Flashcards Preview

Immunology 9.14 > Viruses > Flashcards

Flashcards in Viruses Deck (61):
1

eg. of Helical virus type (3)

RNA only
Measles
Rabies
Tobacco mosaic

2

eg of Icosahedral virus type (3)

DNA or RNA
Herpes simplex
Poliovirus
Poxvirus

3

eg of Complex virus type (3)

Mostly RNA
Bacteriophage
Influenza
Smallpox (DNA)

4

5 stages of viral lifecycle in body

1. Attachment
2. Entry & Uncoating
3. Transcription / Genome replication
4. Assembly (maturation)
5. Release

5

Structure of virus -

Genome (DNA or RNA) inside protein capsid box made of capsomeres.
=NUCLEOCAPSID

If just like this = NAKED
If has lipid bilayer with protein spikes = ENVELOPED

Whole thing together = VIRION

6

Method of attachment to cell

Protein spikes attach to specific cell membrane receptors - some viruses only go into 1 type of cell, others have multiple receptors possible.

7

3 Methods of Entry to cell & how they work:

1. Translocation (poorly understood - goes straight through membrane)
2. Fusion (pH INDEPENDANT) (only enveloped viruses) - cell membrane fuses with viral envelope - nucleocapsid enters cell.
3. Receptor Mediated Endocytosis (pH DEPENDANT). Most common method.
Virus internalized in vacuole, inside vacuole incr. acid by pumping H+ ions in, when pH acid enough - vacuole lyses & release virus)
Naked & enveloped types.

8

Where does genome replication usually occur for RNA and DNA viruses?

RNA - cytoplasm
DNA - nucleus

9

Transcription (Protein creation)
What do DNA viruses use to create mRNA to create proteins

Host DNA dependant RNA polymerase

10

What do most RNA viruses use to create mRNA -- proteins

Their own RNA dependant RNA polymerase creates the mRNA
or
their RNA goes straight to ribosomes as mRNA --> builds RNA polymerase, then use this to create mRNA

11

What do +mRNA viruses use to create proteins

go straight to ribosomes and create from mRNA

12

How do retroviruses enable transcription and translation

they carry viral DNA polymerase - create DNA with this, then use host to creat ds DNA then splice into host DNA for replication & transcription

13

How do DNA viruses replicate their genome

Using host DNA polymerase

14

How do naked viruses exit the cell

Lysis when cell dies

15

How do enveloped viruses exit the cell

Exocytosis - spikes embed into cell membrane, nucleocapsid is enveloped and virus "buds" off from cell.

16

What does "maturation" refer to

When a virus becomes infectious

17

Family, Genome type, Disease:
Rotavirus

DS RNA, Reoviridae, gastroenteritis in kids

18

Family, Genome type, Disease:
Influenza

Orthomyxovirus, -SS RNA, Flu

19

Family, Genome type, Disease:
Parainfluenza

Paramyxovirus, -SS RNA, Resp infection - croup in kids

20

Family, Genome type, Disease:
RSV (Respiratory Syncytial virus)

Paramyxovirus, -SS RNA, Respiratory - bronchioitis in kids

21

Family, Genome type, Disease:
Measles

Paramyxovirus, -SS RNA, Measles - Koplik spots (tongue?) rash

22

Family, Genome type, Disease:
Mumps

Paramyxovirus, -SS RNA, Mumps

23

Family, Genome type, Disease:
Rabies

Rhabdovirus, -SS RNA, Rabies

24

Family, Genome type, Disease:
Norovirus

Caliciviridae, +SS RNA,
Gastro in enclosed communities, eg cruise ships, prisons

25

Family, Genome type, Disease:
Poliovirus

Picornaviridae, +SSRNA,
Polio

26

Family, Genome type, Disease:
Rhinovirus

Picornaviridae - +SSRNA,
Common Cold

27

Family, Genome type, Disease:
Coxsachie = enterovirus

Picornaviridae, +SSRNA
Gastro & hand, foot & mouth in kids

28

Family, Genome type, Disease:
Astrovirus

Astroviridae, +SS RNA
Gastro - adults & kids

29

Family, Genome type, Disease:
Rubella

Togaviridae +SS RNA
Rubella - teratogenic

30

Family, Genome type, Disease:
Coronavirus

Coronaviridae
Resp (common cold) & gastro
SARS

31

Family, Genome type, Disease:
Herpes simplex 1&2

Herpesviridae, DS DNA
Mouth / genital ulcers

32

Family, Genome type, Disease:
Varicella zoster

Herpesviridae, DS DNA
Chickenpox and shingles

33

Family, Genome type, Disease:
Cytomegalovirus

Herpesviridae, DS DNA
CMV = infection of immunocompromised

34

Family, Genome type, Disease:
Epstein barr

Herpesviridae, DS DNA
Glandular fever - infects B cells

35

Family, Genome type, Disease:
Human herpes 6&7

HerpeviridaeDS DNA
Roseola infantum - high fever, then drops, as rash appears & pink spots. not serious common in young kids.

36

Family, Genome type, Disease:
Molluscum contagiosum

Poxviridae DS DNA
Molluscum contagiosum - red papule spots, non painful, bit itchy, contagious, resolveds in 12 months.

37

Family, Genome type, Disease:
Adenovirus

Adenoviridae DS DNA
Upper RT infect & gastro

38

Family, Genome type, Disease:
Papilloma virus

Papillomaviridae DS DNA
Warts

39

Family, Genome type, Disease:
Parvovirus B19

Parvoviridae
Erythema infectiosum (slapped cheek syndrome)

40

Two types of poxviridae - one now eradicated and one used as the vaccine for it.

Variola - smallpox
Vaccinia - vaccine (related to cowpox)

41

Aciclovir (also valaciclovir & famciclovir) is effective against which viruses (2)

Herpes
Varicella zoster

42

Side effects of aciclovir (2)

GI / Neurotoxicity

43

Ganciclovir - good for which virus?

Cytomegalovirus (immunosuppressed)

44

SE of Ganciclovir (4 blood related)

Neutropaenia
Thrombocytopaenia
Leucopaenia
Pancytopaenia

45

Oseltamivir (Tamiflu) - used for what virus?

Influenza

46

SE of oseltamivir (3)

Headache, nausea, cough

47

What does haemagglutinin glycopeptide on influenza membrane do

Binds to sialic acid receptor on cell membrane (eg resp tract cell or rbc)

48

What does neuroaminidase on flu virus do?

Responsible for "budding" virus from cell membrane when leaving human cell.

49

How does aciclovir work

Binds to DNA of herpes and VZ virus - interrupts DNA replication

50

How does oseltamivir work

Combines with neuroaminidase - stops virus from budding from cell

51

What do immunoglobulins attach to on viruses to prevent virus binding to cell & entering

haemagglutinin

52

What phase of viral lifecycle does ganciclovir work at

Replication

53

Where does measles enter the body

Resp tract

54

Where does measles multiply before spreading through the blood

Lymph nodes

55

What receptor, common to many cells, does measles bind to allowing it to act systemically

CD46

56

How does rabies enter body

Via skin - bite

57

How does rabies spread throughout the body

Via PNS then CNS / ANS - nerves basically

58

What 4 cellular responses are there to viral infection

1. Cell death
2. Transformation (retroviruses incorp into DNA)
3. Cell fusion
4. Cytopathic (inclusion bodies within cell)

59

What 3 criteria must ALL be met for the TREATMENT (eg Tamiflu) of influenza in most people?

1. Flu must be circulating (over 100 suspected cases/ 100 000)
2. They are at risk (old, immunocompromised)
3. It is within 48 hrs of onset of symptoms

60

What 4 criteria must ALL be met for PROPHYLAXIS of flu

1. Must be flu circulating
2. Must be at risk (old immunocompr)
3. Must be in contact with person with flu symptoms
4. Not effectively vaccinated

61

What 4 groups are eligible for flu vaccination

1. Over 65s
2. Risk groups (immunocompr)
3. Pregnant women
4. 2-18 yo