Session 8-Blood Borne Viruses:HIV

Question 1

What does HIV stand for?

Answer 1

Human immunodeficiency virus

Question 2

Why is HIV a retrovirus?

Answer 2

ssRNA -> DNA -> ssRNA

Question 3

Which cells does HIV infect?

Answer 3

Cells with CD4 surface receptor

Question 4

True or false: HIV replicates inside cells

Answer 4

TRUE

Question 5

How is HIV transmitted?

Answer 5

Contact of infected bodily fluids with mucosal tissue/blood/broken skin ie:

• sexual contact
• transfusion
• contaminated needles
• perinatal transmission

Question 6

What happens in the primary infection/seroconversion stage of HIV infection?

Answer 6

Virus gains entry locally (lymph tissue) then spreads to blood

Question 7

What happens in the latent stage of HIV infection?

Answer 7

Virus replicates and evades immune system so levels rise

Question 8

What happens in the symptomatic stage of HIV infection?

Answer 8

CD4 count < 350 and people start to feel unwell

Question 9

What happens in the severe/AIDS stage of HIV infection?

Answer 9

CD4 count < 200 and patients have an increased risk of cancer

Question 10

What are the main symptoms of acute HIV infection?

Answer 10

• fever
• weight loss
• headache
• lymphadenopathy
• skin rash
• nausea
• vomiting
• hepatomegaly
• splenomegaly
• myalgia
• oral thrush

Question 11

Which factors affect HIV transmission?

Answer 11

• type of exposure (type of sexual act)
• viral level in blood
• condom use
• breaks in skin or mucosa

Question 12

Which tests are used to diagnose HIV?

Answer 12

• blood tests (serology)
• blood tests (PCR)
• “rapid” test

Question 13

What does serology of HIV detect?

Answer 13

HIV antigen (Ag) and HIV antibody (Ab)

Question 14

What does a PCR of HIV detect?

Answer 14

HIV nucleic acid - detects very early infection (few days)

Question 15

What does a “rapid” HIV test detect?

Answer 15

HIV antibody

Question 16

Patients with which conditions are more at risk of contracting HIV?

Answer 16

• bacterial pneumonia/TB
• meningitis/dementia
• severe psoriasis
• chronic diarrhoea
• lymphoma/anal cancer
• cervical intrapithelial neoplasia (CIN)
• any STI/Hep B/Hep C

Question 17

What are the aims of HIV treatment?

Answer 17

• reconstitute CD4 count
• reduce general inflammation
• reduce risk of transmission
• good quality of life
• normalise lifespan

Question 18

Which strategies are used to treat and reduce the prevalence of HIV?

Answer 18

• anti-retroviral drugs (ARVs)
• increase condom usage
• prevention of mother-to-child transmission
• medical circumcision
• post and pre-exposure prophylaxis

Question 19

Why is a HIV vaccine not possible?

Answer 19

Vaccine would target the envelope proteins but the virus constantly changes these proteins so a vaccine would not be possible

Question 20

Which ARVs are used to treat HIV?

Answer 20

1) two nucleoside reverse transcriptase inhibitors (NRTIs)
AND
2) non-nucleoside reverse transcriptase inhibitor (NNRTI) 
OR
3) protease inhibitor 
OR
4) integrate inhibitor
OR
5) CCR5 entry inhibitor

Question 21

Why are three ARVs given?

Answer 21

There are millions of rounds of viral replication each day and the virus mutates every 2-3 rounds so resistance to the drugs can develop in days. Three drugs makes it harder for a resistance to develop