general virology Flashcards Preview

Microbiology > general virology > Flashcards

Flashcards in general virology Deck (46):
1

Viral structure - types

1. Naked virus with icosahedral capsid
2. Enveloped virus with icosahedral capsid
3. enveloped virus with helical capsid

2

viral genetics - recombination?

exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology

3

viral genetics - Reassortment?

When viruses with segmented genomes exchange genetic materials

4

viral genetics - Reassortment - historical example

the 2009 novel H1N1 influenza A pandemic emerged via complex viral Resentment of genes from human, swine, and avian viruses

5

viral genetics - Complementation?

when 1 of 2 viruses that infect the cell has a mutation that results in a non-functional protein. The nonmutated virus "complements" the mutated one by making a functional protein that serves both viruses

6

viral genetics - Complementation - example

Hepatitis D virus requires the presence of replicating hepatitis B virus to supply HBsAG, the envelop protein for HDV

7

viral genetics - phenotypic mixing?

occurs with simultaneous infection of a cell with 2 viruses. Genome of virus A can be partially coated (forming pseudovirion) with the surface proteins of virus B. Type B protein coat determines the tropism (infectivity) of the hybrid virus. However, the progeny from this infection have a type A coat that is encoded by its A genetic material

8

When viruses with segmented genomes exchange genetic materials --> ????

Reassortment

9

exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology --> ??????

recombination

10

DNA virus - diagram

DNA virus --> 1. complex nucleocapsid 2. icosahedral nucleocapsid
1. DNA virus --> complex nucleocapsid --> envelop --> DS linear --> poxvirade --> a. smallpox b. molloscum contagiosum c. cowpox
2. DNA virus --> icosahedral nucleocapsid --> a. enveloped
b. non envelop
A. DNA virus --> icosahedral nucleocapsid --> enveloped:
- DS circular --> HEPADNAVIRIDAE (HBV)
- DS linear --> HERPESVIRIDAE (HSV1, HSV2, CMV, EBV, HHV6-8, VZV)
B. DNA virus --> icosahedral nucleocapsid --> nonenveloped:
- DS lineae --> Adenoviridae
- DS circular --> Papovaviridae (Papillomavirus, Polyomavirus)
- SS linear --> Parvoviridae (B19)

11

RNA virus are divided to

1. helical nucleocapsid
2. icosahedral nucleocapsid

12

RNA virus - helical nucleocapsid - diagram

helical nucleocapsid --> enveloped:
1. SS- segmented:
a. Bunyaviridae
b. Arenoviridae (Arenovirus)
c. Orthomycoviridae (Influenza A,B,C)
2. SS+ nonsegmented
a. Coronoviridae --> Coronovirus
SS- nonsegmented
a. Filoviridae (filovirus)
b. Rhbdoviridae (lyssavirus)
c. Paramyxoviridae (Parainfluenza, RSV, Measles, Mumps)

13

RNA virus - icosahedral nucleocapsid - diagram

1. Nonenveloped
A. SS+ non-segmented
- Picornaviridae --> a. Rhinovirus B. enterovirus (Poliovirus, Hepatitis A virus, coxsackievirus, echovirus)
- Caliciviridae --> Clicivirus (Norovirus, Hepatitis E)
B. DS segmented --> Reoviridae (Rotavirus, Coltivirus)
2. Enveloped
A. SS+ diploid --> Retrovirus (HIV, HTLV-1, HTLV-2)
B. SS+ non-segmented
- Flaviviridae (Flavivirus)
- Togaviridae (rubella, Eastern equine encephalitis, Western equine encephalitis)
C. SS- circular --> Deltavirus (NOT EXACTLY icosahedral nucleocapsid)

14

DNA viral genome - double vs single strand DNA

ALL DNA viruses except the Parvoviridae (B19) are dsDNA

15

DNA viral genome - linear vs circular

Papilloma- , Polyoma- (circular, supercoiled)
HBV --> circular, incomplete
all other --> linear

16

single strand DNA virus

Parvoviridae (B19)

17

circular DNA virus

Papilloma- , Polyoma-, HBV

18

RNA viral genomes - double vs single strand RNA

ALL single except Reoviridae (Rotavirus, Coltivirus)

19

DS RNA virus

Reoviridae (Rotavirus, Coltivirus)

20

Naked viral genome infectivity

Purified nucleic acids of most dsDNA (except poxvirus and HBV) and SS+ RNA viruses are infectious. Naked nucleic strand SS- RNA and dsRNA viruses are not infectious (they require polymerases contained in the complete virus, not parvoviridae)

21

which virus, their naked genome form is not infectious

Naked nucleic strand SS- RNA and dsRNA viruses are not infectious, HBV poxvirus and ssDNA
(they require polymerases contained in the complete virus, not parvoviridae)

22

which virus, their naked genome form is infectious

Purified nucleic acids of most dsDNA (except poxvirus and HBV) and SS+ RNA viruses are infectious.

23

viral replication - area of replication

all DNA viruses except poxvirus in the nucleus
all RNA viruses except influenza virus and retrovirus in the cytoplasm

24

DNA virus that is not replicate in the nucleus

poxvirus

25

RNA virus that is not replicate in the cytoplasm

influenza virus and retrovirus

26

Viral envelopes - enveloped viruses acquire their envelops from?

generally, enveloped viruses acquire their envelops from plasma membrane when they exit from cell.
Exceptions include herpesvirus, which acquire envelopes from nuclear membrane

27

viruses that acquire their envelops from nuclear membrane

herpesvirus

28

All DNA viruses are double stranded except

parvovirus (single stranded)

29

DNA viruses capsid shape

alla icosahedral except pox (complex)

30

DNA viruses replicate ... (where)

in the the nucleus
except pox

31

all DNA viruses replicate in the nucleus except .... (why)

pox - carries its own DNA-depended RNA polymerase

32

Viral vaccines - categories

1. Live attenuated vaccines
2. Killed
3. Subunit

33

Viral vaccines - Killed (VIRUS)?

1. Rabies
2. Influenza (injected)
3. Salk Polio
4. HAV

34

Viral vaccines - subunit (VIRUS)?

HBV (antigen=HBsAg)
HPV (types 6, 11, 16, 18)

35

Viral vaccines - Live attenuated vaccines (VIRUS)?

1. smallpox
2. yellow fever
3. rotavirus
4. VZV
5. Sabin polio
6. Influenza (intransal)
7. Measles
8. Mumps
9. Rubella

36

Viral vaccines - Live attenuated vaccines vs killed/inactivated - mechanism

Live attenuated vaccines --> induce humoral and cell-mediated immunity
killed/inactivated --> induce only humoral immunity

37

Viral vaccines - killed/inactivated - advantages

stable - not revert to virulence

38

Viral vaccines - Live attenuated vaccines - advantages

no booster needed
induce both humoral and cell-mediated immunity

39

Viral vaccines - Live attenuated vaccines - disadvantages

- have reverted to virulunce on rare occasions
- dangerous to give live vaccines to immunocompromised patients

40

Viral vaccines - killed/inactivated - disadvantages

induce only humoral immunity
boosters may needed

41

which vaccines should not be given to patients with a history of anaphylactic reaction to eggs (why)

1. influenza
2. measles
3. mumps
4. yellow fever
grown in chick ebryos

42

DNA virus - diagram

DNA virus --> 1. complex nucleocapsid 2. icosahedral nucleocapsid
1. DNA virus --> complex nucleocapsid --> envelop --> DS linear --> poxvirade --> a. smallpox b. molloscum contagiosum c. cowpox
2. DNA virus --> icosahedral nucleocapsid --> a. enveloped
b. non envelop
A. DNA virus --> icosahedral nucleocapsid --> enveloped:
- DS circular --> HEPADNAVIRIDAE (HBV)
- DS linear --> HERPESVIRIDAE (HSV1, HSV2, CMV, EBV, HHV6-8, VZV)
B. DNA virus --> icosahedral nucleocapsid --> nonenveloped:
- DS lineae --> Adenoviridae
- DS circular --> Papovaviridae (Papillomavirus, Polyomavirus)
- SS linear --> Parvoviridae (B19)

43

RNA virus - helical nucleocapsid - diagram

helical nucleocapsid --> enveloped:
1. SS- segmented:
a. Bunyaviridae
b. Arenoviridae (Arenovirus)
c. Orthomycoviridae (Influenza A,B,C)
2. SS+ nonsegmented
a. Coronoviridae --> Coronovirus
SS- nonsegmented
a. Filoviridae (filovirus)
b. Rhbdoviridae (lyssavirus)
c. Paramyxoviridae (Parainfluenza, RSV, Measles, Mumps)

44

RNA virus - icosahedral nucleocapsid - diagram

1. Nonenveloped
A. SS+ non-segmented
- Picornaviridae --> a. Rhinovirus B. enterovirus (Poliovirus, Hepatitis A virus, coxsackievirus, echovirus)
- Caliciviridae --> Clicivirus (Norovirus, Hepatitis E)
B. DS segmented --> Reoviridae (Rotavirus, Coltivirus)
2. Enveloped
A. SS+ diploid --> Retrovirus (HIV, HTLV-1, HTLV-2)
B. SS+ non-segmented
- Flaviviridae (Flavivirus)
- Togaviridae (rubella, Eastern equine encephalitis, Western equine encephalitis)
C. SS- circular --> Deltavirus (NOT EXACTLY icosahedral nucleocapsid)

45

close contacts to immunocomproimsed patients - livce vaccines

its ok except live polio or influenza

46

Live attenuated vaccines - HIV

MMR, + VZV can be given to HV +