HIV Intro Flashcards
Differentiate between HIV 1 and HIV 2
Common?
Progression?
Transmissibility?
Location?
Testing?
Common?
- HIV-1 more common
Progression?
- HIV-2 immunodeficiency progresses slower
Location
- HIV-2 is mostly in west Africa
Transmissibility?
- HIV-2 is less transmissible
Testing
- HIV-1 tests do not reliably detect or quantify HIV-2
Where are the majority of people living with HIV
Africa
How is the progress on HIV treatment in Canada
% Diagnosed with HIV
% On treatment
% on treatment suppressed
89% know their HIV status
85% positive for HIV initiate treatment
95% on treatment are virally suppressed
What type of virus HIV?
What does it attack
Retrovirus (RNA virus with DNA intermediate)
Attacks the CD4 lymphocytes
- type of WBC required for immunity against bacteria, viruses, and parasites
How does HIV attack CD4 cells (2)
Progressive depletion of CD4 cells due to
- Decrease production
- Increase destruction
What is the HIV life cycle (6)
- Attachment and fusion
- HIV will bind CD4 cell
- Capsid (genetic material) released into cell and nucleus - Reverse transcription
- HIV’s reverse transcriptase converts single-stranded HIV RNA into double-stranded DNA - Integration
- Integrase hides virus DINA into host DNA in a loop
- Becomes a pro-virus (can remain dormant for years) - Transcription and translation
- When provirus is activated, RNA polymerase will begin making virus DNA into RNA
- Long viral proteins are made - Assembly
- Proteases will chop up virus protein chains into smaller individual proteins
- Small proteins come together to make new HIV particles - Budding
- New virus particle will exist cell via budding (taking part of CD4 human membrane with it) - destroys CD4 human cell
How is HIV transmitted?
What must it come in contact with
Bodily fluids
- Blood
- Breast milk
- Vaginal fluids
- Semen
- pre-seminal fluid
- Rectal fluids
Must come in contact with
- Mucous membrane
- A damaged tissue
- Injected in blood stream
How is HIV not transmitted
- Air or water
- Saliva, sweat, tears, closed-mouth kissing
- Insects or pets
- Sharing toilets, food, or drinks
What is the usual range of CD4 for those w/o HIV infection
500-1200 cells (~800)
What is the danger zone of CD4 counts where opportunistic infections can prevail
<200 cells
T/F You can have HIV without Aids
True
- AIDS is the last stage of the HIV disease
What does having AIDs means? (2)
- CD4 count <200 cells (or CD4% <14%)
OR
Presence of an AIDs-defining condition
(candidiasis, lymphoma, pneumonia)
What is the presentation of acute HIV infection? (7)
Onset?
- Fever
- Fatigue
- Swollen lymph nodes
- Sore throat
- Muscle/joint pain
- Maculopapular rash on the trunk
- Night sweats
Within 2-4 weeks after exposure
What does the RNA test determine?
HIV viral load
What does the HIV p24 antigen determine
Viral protein that makes the HIV core
- useful for diagnosing EARLY infection (acute) when antibody levels are below detection limits
Which antibodies does the HIV antibody test for? (2) What is the onset?
IgM antibodies
- produced after exposure to an infection
- ~3 weeks
IgG antibodies:
- A later response to infection
- ~infection
What does the 4th generation HIV antibody test for?
HIV antigen AND p24 antigen (sooner detection ~ 16 days)
What are the current recommendations for HIV testing in order (3)
- 4th gen test (HIV antibody + p24 antigen)
- Differentiation immunoassay (HIV-1 or HIV-2)
- If negative/intermediate, perform a NAT (PCR) - detects HIV RNA or DNA in WBCs
What do the Point of Care HIV rapid test detect?
What is the recommendation of when to test?
Detects HIV antibodies ONLY (3rd gen)
Test at baseline, 3 weeks, 6 weeks, 3 months
When was triple therapy and viral load testing discovered
1996
What are the goals of HIV drug therapy (5)
- Suppress HIV replication
- <40 copies/mL - Restore/preserve immune system
- aim for absolute - Reduce HIV-associated morbidity
- Prolong duration and quality of survival
- Prevent HIV transmission
Which surrogate markers are good indicators of treatment response? (2)
Onset?
Statistically significant values?
HIV RNA/HIV Viral load
- less HIV RNA after starting treatment (dec risk of progression to AIDs or death)
- Minimal statistically significant HIV RNA change is 3-FOLD
- Should have viral suppression 8-24 weeks after treatment (if adherent)
Protease inhibitor may take up to 24 weeks
Which surrogate marker is an indicator of immune function in PLWH?
What response do you expect in an older age or a low CD4 count patient with this surrogate marker?
CD4 count
- strongest predictor of disease progression and survival
- important for starting prophylaxis for opportunistic infection
- assess urgency to initiate antivirals
If low CD4 count at baseline or OLDER AGE
- a blunted increase in CD4 counts (despite antivirals)
T/F A poor CD4 response in a patient with viral suppression is an indication to modify ARV
False
