HIV Epidemiology, Global Health and Aids

Question 1

What happens in HIV?

Answer 1

Excessive cell apoptosis

Question 2

What signs and symptoms are present in someone with HIV?

Answer 2

Weight loss, recurrent and respiratory infections, fever, TB

Question 3

What immune cells does HIV affect?

Answer 3

CD4 deficiency, B cell and adaptive immunity is active

Question 4

What are 4 causes of AIDS?

Answer 4

1) HIV
2) Cancer
3) Having chemotherapy
4) Taking immunosuppressants

Question 5

What 4 problems surround HIV treatment?

Answer 5

1) Taboo factor of transmission –> Sex transmits it
2) Latent Period –> Infect others unknowingly
3) HIV increased risk of infection from weakened immune system
4) Drug treatment is difficult due to lots of mutations

Question 6

What enzyme copies HIV RNA into DNA?

Answer 6

Reverse Transcriptase

Question 7

Why are mutations common in HIV?

Answer 7

Retrovirus, replicates by Reverse Transcription, causing errors and mutations

Question 8

What genus does HIV belong to and what is the main characteristic of it?

Answer 8

Lentivirus –> Long incubation period

Question 9

What is the origin of HIV?

Answer 9

SIV (Simian IV) –> Brought about by Chimpanzees

Question 10

What cells act as ‘host cells’ for HIV?

Answer 10

CD4+ cells, macrophages and dendritic, can be invaded by HIV

Question 11

How does HIV affect CD4 count?

Answer 11

Uncontrolled CD4 activation and apoptosis, which sees CD4 numbers decrease over time

Question 12

Which glycoproteins do you find on the surface of HIV?

Answer 12

GP41, GP120

Question 13

How does a HIV particle bind onto a cell surface?

Answer 13

GP160 binds to a CD4 receptor and CCR5 co-receptors

Question 14

What part of HIV enzymes the host cell after attachment?

Answer 14

Viral Capsid, Enzymes, Nucleic Acid

Question 15

What 4 enzymes are involved in HIV replication?

Answer 15

1) Reverse Transcriptase
2) Integrase
3) Proteases
4) RNA polymerase

Question 16

What is the mechanism for HIV viral replication?

Answer 16

1) GP160 binds to CD4 receptors of a cell
2) Viral Capsid, enzymes and nucleic acid are all uncoated and enter the cell
3) RNA is converted into DNA using Reverse Transcriptase
4) Viral DNA is integrated into the cell using integrase
5) Viral DNA is transcribed into Viral Proteins
6) Splicing
7) New HIV cells bud from CD4

Question 17

What are the main steps of HIV replication?

Answer 17

1. Attachment.
2. Cell entry.
3. Uncoating.
4. Reverse transcription.
5. Genome integration.
6. Transcription of viral DNA.
7. Splicing of mRNA.
8. Translation into proteins.
9. Assembly.
10. Budding.

Question 18

How many genes are encoded in the HIV genome?

Answer 18

9

Question 19

What gene encodes reverse transcriptase and what does it encode overall?

Answer 19

Pol

Enzymes

Question 20

How are macrophages also at risk of being infected by HIV?

Answer 20

Macrophages contain CD4 and CCR5 receptors

Question 21

What are the steps of initial HIV infection?

Answer 21

1) HIV enters via the mucosa
2) Macrophages ingest HIV, presenting an epitope of HIV to a T cell
3) HIV infects T cell
4) Infection into the blood stream (Viraemia)

Question 22

How are immune system cells affected by HIV and immune dysfunction?

Answer 22

1) CD4 excessively/inappropriately activated
2) Impaired IL-2 production
3) CD4 function and number decrease
4) Less AB’s are produced by B cells
5) decrease in neutrophils, macrophages and natural killer cells

Question 23

What are the 4 sanctuary sites for HIV?

Answer 23

1) Genital Tract
2) Bone Marrow
3) CNS
4) GI Tract

Question 24

What is the main treatment for HIV?

Answer 24

Anti-Retroviral Treatment (ART)

Combination of medicines, to reduce replication and slow spread and transmission