Infection 3 HIV

Question 1

Structures of a virus

Answer 1

Genome - RNA/DNA
Capsid - protein cell
Lipid envelope- yes/no
Replication strategy

Question 2

Shapes of capsid in virus

Answer 2

Helical - rod shaped or coiled
Icosahedral - spherical

Question 3

What is the capsid in a virus?

Answer 3

Protein shell which protects the genome

Question 4

How does HIV infect the cell?

Answer 4

Infects with CD4 surface receptor
Replicates inside the cell - destroys cell
- causes inflammation
- infects more cells

Question 5

Modes of transmission of HIV

Answer 5

Contact of infected bodily fluids
Medical procedures e.g. skin graft, organ donation
Sexual contact
Mother to baby
Contaminated needles

Question 6

HIV symptoms

Answer 6

oral candidiasis
Kaposi’s sarcoma
PCP - pneumocystis pneumonia
Fever
Weight loss
Malaise
Headache
Thrush
Rash
Nausea + vomiting
Sores in mouth + oesophagus

Question 7

Two types of test for HIV

Answer 7

Blood tests
Rapid tests

Question 8

Two types of blood tests for HIV

Answer 8

Serology
PCR

Question 9

What does HIV serology detect?

Answer 9

HIV antigens Ag
HIV antibodies Ab

Question 10

Speed of serology

Answer 10

Same day result

Question 11

Are false negatives/positives possible in serology?

Answer 11

False negative possible

Question 12

What does HIV PCR detect?

Answer 12

HIV nucleic acid
highly sensitive - detects early infection

Question 13

What is PCR used for in HIV testing?

Answer 13

Follow up/treatment response

Question 14

What do rapid HIV test detect?

Answer 14

HIV antibody in blood and saliva

Question 15

What do you use for rapid HIV tests?

Answer 15

Blood test - finger prick
Oral - saliva
At home testing

Question 16

What do you do if you get positive or negative rapid HIV test?

Answer 16

Negative - accurate
Positive - confirm with serology

Question 17

Treatment of HIV

Answer 17

No cure - management needed
Anti-retroviral drugs
Testing + screening
Condom usage
PrEP - pre exposure prophylaxis
PEP - post exposure prophylaxis

Question 18

How are anti-retroviral drugs used in HIV?

Answer 18

Mix 2 nucleoside reverse transcriptase inhibitor with one of: protease inhibitor OR integrate inhibitor OR CCR5 inhibitor

Question 19

Reason for anti-retroviral drugs mixing

Answer 19

To overcome drug resistance + viral mutations

Question 20

what is HIV?

Answer 20

• a ssRNA retrovirus which infects cells with CD4+ surface receptors
• replicates inside cell&raquo_space; destroys cell, causes inflammation + spreading

Question 21

outline retrovirus replication

Answer 21

• virus binds to CD4+ on cell surface
• virus penetrates + infects cell
• viral ssRNA > dsDNA by reverse transcriptase
• viral DNA is integrated into host DNA by integrase
• viral DNA is transcripted during cell division
• viral protein chain assemble + bud out of cell
• virus matures as chain is cut by proteases

Question 22

what are the main symptoms of acute HIV infection regarding:
- systemic
- lymph nodes
- skin
- gastric
- muscle
- mouth

Answer 22

• systemic - weight loss, fever
• lymph nodes - lymphadenopathy
• skin - rash, Kaposi’s sarcoma
• gastric - nausea, vomiting
• muscle - myalgia (pain)
• mouth - sore, thrush

Question 23

what factors affect HIV transmission?

Answer 23

condom usage
type of exposure
breaks in skin
viral level in blood

Question 24

what 4 factors allow people with HIV to live healthy lives?

Answer 24

• early detection
• treatment
• adherence
• healthy living

Question 25

aims of HIV treatment

Answer 25

reduce general inflammation
reduce risk of transmission
normalise lifespan + QoL
reconstitute CD4 count

Question 26

Is HIV single/double stranded + RNA or DNA?

Answer 26

Single stranded RNA

Question 27

What is the most common opportunistic infection in a patient with HIV?

Answer 27

Pnuemocystis jiroveci

Question 28

What count of CD4+ leads to progression into AIDs?

Answer 28

<200