ð åèç
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è â HIV Types
- HIV-1: worldwide main, multiple subtypes (M most common; subtypes A-K, recombinants)
- HIV-2: W Africa, slower progression, NNRTI-resistant
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è â Receptor
- CD4 + CCR5 or CXCR4 co-receptor
- Macrophage-tropic (CCR5) early; T-cell-tropic (CXCR4) late
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è â Acute Retroviral Syndrome
- Mononucleosis-like: fever, LAP, rash, pharyngitis, myalgia 2-4 wk post-exposure
- ~ 50% symptomatic
- Many missed
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è â Global Stats (2023 UNAIDS)
- 39M living with HIV
- 1.3M new infections/yr
- 630K deaths/yr
- 95-95-95 target by 2030
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è â Transmission Risk
- Receptive anal: 1.4% per act
- Receptive vaginal: 0.08% per act
- Vertical without prevention: 25-30%; with prevention < 2%
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è â U=U (Undetectable = Untransmittable)
- Sustained VL < 200 copies/mL on ART = no sexual transmission
- PARTNER trials documented
- Major messaging
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è â Diagnosis
- 4th-gen combo test (Ab + p24 antigen) = primary screening (window 2-3 wk)
- HIV-1/HIV-2 differentiation = confirmatory
- HIV RNA PCR = acute infection or pediatric
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è â Universal Screening
- All 13-64 yr at least once (CDC, USPSTF)
- High-risk: annual
- Pregnancy: each pregnancy
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è â Stages
- Acute (weeks 1-4)
- Clinical latency (years)
- AIDS (CD4 < 200 or AIDS-defining illness)
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è â Reservoirs
- Resting memory CD4+ T cells
- Macrophages, microglia
- Major obstacle to cure