HIV & AIDS Symposium Flashcards
How can HIV be transmitted?
- Sexual contact
- Blood-Blood
- Infected blood products
- In Utero
- Breast milk
Which is more common HIV 1 or HIV 2?
HIV 1
HIV 2 less easily transmitted and less pathogenic
What are the three main groups of HIV 1
- ) MAIN
- ) NEW
- ) OUTLIER
In what part of the world is HIV-2 confined to
West Africa
Describe the structure of the HIV virus
- 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
Describe the course of infection of the HIV virus
- 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)
Name 3 bacterial opportunistic infections
- Mycobacterium tuberculosis
- Salmonella
- Streptococcus, Haemophilus, pneumococcus
Name 2 protozoa opportunistic infections
- Cryptosporidium (chronic diarrhoea)
* Toxoplasma gondii (disseminated, including CNS - from cats)
Name 3 Fungal opportunistic infections
- Candida - oral presentation
- Cryptococcus neoformans - CNS
- Pneumocystis jiroveci - pneumonia
Name 3 Virus opportunistic infections
- HSV - herpes simplex virus
- EBV - hairy leukoplakia
- HHV-8 Kaposis sarcoma
What are Drug targets for HIV
- 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
What are the side effects of the NRTIs
- AZT - headaches and nausea, anaemia
* Stavudine-lactic acidosis, lipoatrophy and peripheral neurpathy
What are the side effects of NNRTIs (non nucleoside reverse transcriptase inhibitors)
- Stevens Johnson Syndrome: a severe disorder of mucous membranes
- Tetratogenecity
Whats are the side effects of PIs
lipodystrophy - fat loss from legs, fat gain
What is the risk of dental transmission of HIV
1 in 300 - low