HIV and AIDS - presentation
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HIV and AIDS - presentation
pharmacology HIV antiretrovirals
HIV and Aids as taught by Ronnie Chan
What does HIV and AIDS stand for?
HIV (Human Immunodeficiency virus)
AIDS (acquired immunodeficiency syndrome)
What is the HIV and what does it contain?
An RNA retrovirus - subfamily Lentivirus
Contains 2 copies of RNA
: Reverse transcriptase
Two major envelope proteins
: GP120 (docking)
Requires host DNA to replicate and produce proteins
What are the types of HIV and what are there properties?
Types HIV 1 HIV 2
virulence High Low
infectivity High Low
prevalence Most common Uncommon, found in
globally West Africa
binding site CCR5 CXCR4 co-receptor
Common HIV host cell and why?
CD4 T cells are most commonly infected. High affinity for gp120.
Acute phase death - cytopathic damage by virus
Chronic death - chronic activation of T cells
inhibition of thymic output of T cells
suppression of the bone marrow
destruction of lymph-node architecture
low-level ongoing infection of memory CD4 T cells
What are the methods of transmission?
Sexual - anal, vigina (homo=men, hetro=women (most common))
Percutaneous - rarely transfusions, needle sharing, needle stick
Vertical - transplacental, periparium, breast milk ingestion
What are the stages associated with HIV infection?
Stage 1 - Primary - cold or flu-like symptoms. Antibody test usualy negative, becomes positive after 3-6months (6m = 95%) seroconversion.
Stage 2 - Asymptomatic - average duration 10 years. Symptom free, may have swollen glands.
Stage 3 - Symptomatic - immune system deteriorates. CD4 count below 500 = risk of opportunistic infections.
Stage 4 - HIV to AIDS. Advanced HIV when CD4 count below 200. Need AIDS defining illness or infection.
What tests are available for HIV testing?
Screening tests - ELISA or EIA - rapid testing - whole blood, plasma, saliva or urine test.
Confirmatory tests - Western Blot analysis, RT-PCR)
Rapid HIV antibody test - sensitive and specific 99%. Results on 5 to 40 minutes
HIV viral load - first choice for diagnosing acute HIV
HIV p24 antigen - first antigen to be elevated in acute HIV. Can be used for acute diagnosis
What classes of drug are available to reduce the progression of HIV?
RTI - Reverse-Transcriptase Inhibitors
PI - Protease Inhibitors
Entry (fusion) Inhibitors
Maturation Inhibitors (new class)
What are the three forms of RTI?
- NARTI or NRTI - Nucleoside analogue reverse-transcriptase inhibitors.
- NtARTI or NtRTI - Nucleotide analogue reverse-transcriptase inhibitors
- NNRTI Non-nucleoside reverse-transcriptase inhibitors
What are the main reasons for HAART?
Highly active antiretroviral therapy is used to:
reduce the toxic effects of the drugs,
to increase the time it takes for resistance to occur,
restore sensitivity in some cases,
slow the progression of the disease,
fewer opportunistic infections,
improve or stabilise immunity,
suppress HIV replication.
What is a typical combination therapy?