HIV symposium

Question 1

What does HIV stand for?

Answer 1

Human Immunodeficiency Virus

Question 2

What does AIDS stand for?

Answer 2

Acquired Immune Deficiency Syndrome

Question 3

How is HIV transmitted?

Answer 3

Sexual contact - usually homosexual but increasing heterosexual 
Blood 
Infected blood products
In utero 
Breast milk

Question 4

Types of HIV? Which is most common?

Answer 4

HIV 1 = most common

HIV 2 = less easily transmitted and less pathogenic

Question 5

What are the 3 main groups of HIV-1?

Why are there many groups?

Answer 5

Main (M - pandemic trains)
New (N)
Outlier (0-confined to Cameroon area)
Many groups as HIV mutates readily - reverse transcriptase does not proofread = new versions of genes

Question 6

Where is HIV-2?

Answer 6

West Africa

Question 7

Origin of HIV-1?

How was further spread achieved?

Answer 7

Cameroonian Chimps via hunting

Further spread by urbanisation, diamonds, rail travel

Question 8

HIV virus structure?

Answer 8

Adhesins on the outside - gps120 which binds to the cell receptor
Lipid coat = virus less resistant to survival outside host
Single stranded RNA genome
Contains enzymes to make new copies of itself

Question 9

What does HIV infect?

Answer 9

gp120 binds to CD4 (T lymphocyte and immune cells)
Followed by co-receptor binding (CCR5/CXCR4 co-receptor):
- People with CCR5 mutations are resistant
- Occurs in 2-14% europeans

Attachment is followed by membrane fusion and internalisation (gp41 dependent)
Integration into host genome
Cells activated = viral proteins produced and thousands of new virus progeny synthesised

Question 10

Why so much CCR5 resistant caucasian people in Europe?

Answer 10

CCR5 mutation is 3000 years old
Selective pressure
Founder effect

Question 11

Virus variation during HIV infection?

Answer 11

• Isolates from early in infection- CCR5 (M)
  macrophage tropic and low cytopathic effect- more transmissable
• Isolates from late infection- CXCR4 (T)
  high cytopathic ability – less transmissable

Question 12

How does the infection enter the body?

Answer 12

Blood, colon-rectum, vagina

Question 13

When do constitutional symptoms from HIV start e.g. weightloss?

Answer 13

Number of T cells cannot cope for the number of virus = constitutional symptoms

Question 14

Name the oral manifestations and presentation of HIV?

Answer 14

Thrush - white tongue
Erythematous candidosis = red patches buccal mucosa
Gingival erythema as rxns to bacteria present in mouth
Hairy leucoplakia = white striations on side of tongue

Question 15

When does HIV progress to AIDS?

Answer 15

When HIV untreated
10% HIV infected subjects progress within 2-3 yrs
5-10% clinically asymptomatic after 10 yrs
Remaining subjects progress to AIDS within 10 yrs - death
Improved by antiretroviral therapy

Question 16

Number of people with HIV?

Answer 16

36.7 Million

Question 17

AIDS epidemic?

Answer 17

Homosexual 57.5%
Heterosexual 39%
IVDU 3%
Mother child 0.5%

Question 18

HIV drug targets?

Answer 18

Fusion inhibitors
NRTIs ('nucleotide reverse transcriptase inhibitor')
NNRTI (non '')
Intergrase inhibitors
Protease inhibitors
CCR5 entry inhibitors

Most use a combo of these drugs

Question 19

How to treat HIV?

Answer 19

Highly Active Anti-Retroviral Therapy
1st line:
- 2 NRTIs (must manage side effects)
- 1 NNRTI - inactive against HIV-2

OR a protease inhibitor - high turnover in body = many pills = boosted with Ritonavir to improve efficacy
OR an integrase inhibitor

Question 20

Side effects of NRTIs?

Answer 20

AZT- headaches and nausea, anaemia, neutropenia
Stavudine-lactic acidosis, lipoatrophy (loss from face and limbs – gain to neck and tummy) and peripheral neuropathy- possibly via mitochondrial toxicity
Rashes

Question 21

Side effects of NNRTIs?

Answer 21

Stevens Johnson Syndrome: a severe disorder of mucous membranes
Teratogenecity

Question 22

Side effects of Protease Inhibitors?

Answer 22

lipodystrophy- fat loss from legs, fat gain-pot belly

Question 23

Dental transmission control of HIV?

Answer 23

Normal infec control procedures
Gloves
Sterilise instruments
Dispose of sharps
Suction
Care if blood spillage

If at risk - Occupational heath: Prophylactic HAART and HIV testing

If needlestick: PEP administration

Question 24

How to test for HIV?

Answer 24

ELISA based blood tests - detects HIV antibodies in blood
Antibody takes 6-12 weeks to develop
Most reliable testing at 3 months
Babies may test pos from maternal antibody PCR test