Viruses and infection Flashcards

1
Q

What must viruses do in order to transmit?

A

Replicate inside the host

Viruses must evade or suppress host responses

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

What is the host environment like?

A

Hostile

Innate and adaptive immune responses

Cells are inherently antiviral - virus sensing

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

Why do symptoms of viral disease arise?

A

Virus wanting to transmit - cough and diarrhea

Host responding to virus - fever

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

What is the shape of HIV?

A

Cone-shaped

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

What cells does HIV infect?

A

Activated CD4 T cells

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

Where on the CD4 T cells do HIV bind?

A

CCR5 co-receptors

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

Course of HIV progression

A

High level of viremia at beginning of the disease

Viral set point is reached

CD4 cell death and viral replication remains high byt CONSTANT

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

Does the viral set point vary from person to person?

A

Yes

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

What happens to the course of HIV progression without treatment?

A

CD4 levels continue to drop

Too low levels = immunocompromised

Susceptibel to opportunistic infections

AIDS develops and eventually death

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

What is a common feature of RNA viruses?

A

Vast turnover

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

Why do RNA viruses have such a high turnover?

A

RNA polymerase and reverse transcriptase don’t have the proofreading and error correcting functions as DNA polymerase

Every time a virus divides, mutations or errors happen to the structure

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

What is a quasispecies?

A

Accumulation of diversity of viruses

Viruses related by a single or multiple mutations

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

What are the implications of the vast turnover of viruses?

A

Profound implications for

Immunity

Developing vaccines

Drug therapy

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

What is a phylogenetic tree?

A

Tree showing the varying HIV sequences within a single individual

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

What is the difference between the flu and HIV?

A

HIV develops mutations within a host

Flu does not develop mutations within a host

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

What are the two mechanisms by which the flu changes genetically?

A

Antigenic shift

Antigenic drift

17
Q

What is the main difference between antigenic shift and antigenic drift?

A

Antigenic shift - more radical changes in the antigenic profile of the flu virus

Antigenic drift - gradual change in the genes encoding the Haemagglutinin receptor

18
Q

Antigenic shift is the cause of the flu pandemic

TRUE or FALSE

A

TRUE

19
Q

Describe effect of antigenic shift on the flu

A

Influenza is a negative sense RNA virus

Genome made up of 8 segmented RNA molecules

Each molecule codes for one protein

A consequence of this - if two virus strains infect the same cell, there is segment reassortment between 8 molecules

20
Q

Describe effect of antigenic drift on the flu

A

Gradual change in the genes encoding Haemagglutinin receptors

Antibody won’t bind to the genetically mutated Hg

21
Q

What type of virus infection is HIV?

A

Persistent

Clinical latency

Infection occurs as a result of decreasing CD4 numbers

Increase in likelihood of opportunistic infection

Evades immunity by changing faster that the body can develop antibodies

22
Q

What type of virus infection is Influenza?

A

Acute infection

Rapid onset of illness and immune clearance

Shift in strain leads to pandemic

23
Q

What types of virus infection is herpes?

A

Latent

Periodic peaks of viral load interstersed by nothing

Interplay between replication of the virus and immune system