HIV & AIDS Symposium

Question 1

How can HIV be transmitted?

Answer 1

• Sexual contact
• Blood-Blood
• Infected blood products
• In Utero
• Breast milk

Question 2

Which is more common HIV 1 or HIV 2?

Answer 2

HIV 1

HIV 2 less easily transmitted and less pathogenic

Question 3

What are the three main groups of HIV 1

Answer 3

1. ) MAIN
2. ) NEW
3. ) OUTLIER

Question 4

In what part of the world is HIV-2 confined to

Answer 4

West Africa

Question 5

Describe the structure of the HIV virus

Answer 5

• Capsid in centre that protects a single stranded RNA genome
• Contains enzymes to copy itself
• Contains reverse transcriptase to turn RNA into DNA
• Contains glycoproteins on its surface:
• gp41
• gp120

• Has lipid envelope derived from the host

Question 6

Describe the course of infection of the HIV virus

Answer 6

• Initial attachment via gp120 on virus binding to CD4 on target cell
• the cytokine receptor CD4 is present only on immune cells - specifically T-cells and macrophages
• For strong binding there is a co-receptor called CCR5/CXCR4 that must also bind

• People with CCR5 mutations are resistant
(Heterozygous = reduced susceptibility)
(Homozygous = resistant)

• Post attachment by gp120. The virus enters the cell cytoplasm (requires gp41).
• The virus uncoats and releases reverse transcriptase and the single stranded RNA that reverse transcribes into DNA.
• The DNA in the nucleus then incorporated not the host genome
• When the T-cell is challenged with a foreign body it produces RNA and therefore viral proteins.
• More viruses are produced to kill more T-cells (auto-immune)
• An opportunistic infection is what kills the human not the disease itself (immune system drained)

Question 7

Name 3 bacterial opportunistic infections

Answer 7

• Mycobacterium tuberculosis
• Salmonella
• Streptococcus, Haemophilus, pneumococcus

Question 8

Name 2 protozoa opportunistic infections

Answer 8

• Cryptosporidium (chronic diarrhoea)

* Toxoplasma gondii (disseminated, including CNS - from cats)

Question 9

Name 3 Fungal opportunistic infections

Answer 9

• Candida - oral presentation
• Cryptococcus neoformans - CNS
• Pneumocystis jiroveci - pneumonia

Question 10

Name 3 Virus opportunistic infections

Answer 10

• HSV - herpes simplex virus
• EBV - hairy leukoplakia
• HHV-8 Kaposis sarcoma

Question 11

What are Drug targets for HIV

Answer 11

• Fusion inhibitors
• NRTIs (nucleoside reverse transcriptase inhibitors) - nucleotide analogues cause chain termination when RT builds DNA from RNA
• Integrase inhibitors
• PI (protease inhibitors)
• CCR5 entry inhibitors

Question 12

What are the side effects of the NRTIs

Answer 12

• AZT - headaches and nausea, anaemia

* Stavudine-lactic acidosis, lipoatrophy and peripheral neurpathy

Question 13

What are the side effects of NNRTIs (non nucleoside reverse transcriptase inhibitors)

Answer 13

• Stevens Johnson Syndrome: a severe disorder of mucous membranes
• Tetratogenecity

Question 14

Whats are the side effects of PIs

Answer 14

lipodystrophy - fat loss from legs, fat gain

Question 15

What is the risk of dental transmission of HIV

Answer 15

1 in 300 - low

Question 16

How do we test for HIV?

Answer 16

• Most testing is ELISA based blood test - detects HIV antibodies in the blood
• Antibody takes 6-12 weeks to develop
• Most reliable testing at 3 months
• Babis may test +ve from maternal antibody PCR test
• Home test kits exist but blood test most reliable