MI3.13 | HIV/AIDS — Epidemiology, Evolution & Opportunistic Infections — Summary & Reflection

REFLECT

Return to the opening case — the 32-year-old lorry driver with CD4 78 cells/μL, oral candidiasis, AFB in sputum, and GMS-positive organisms in BAL.

• He has two simultaneous OIs: TB (CD4 200–500 zone) AND PCP (CD4 <200). Is it unusual to have both?
• ART is indicated immediately. But starting ART within 2–4 weeks of ATT carries IRIS risk. How would you counsel him and his family about this?
• His wife is asymptomatic but wants HIV testing. Which test should she receive, and what is the window period she should understand?
• The patient says: "I always used a condom." Which route of transmission is most likely for a truck driver in India, and how might you frame the discussion without stigmatising him?

This is not just microbiology — it is clinical medicine, counselling, and public health in one patient.

KEY TAKEAWAYS

HIV Structure: Retrovirus; gp120 binds CD4 + CCR5/CXCR4 co-receptor; reverse transcriptase (error-prone → drug resistance); integrase; protease

Transmission: Sexual (commonest in India), IVDU, vertical (mother-to-child), blood products; NOT by casual contact

Natural history (CD4 progression):
- Primary illness (high VL, acute seroconversion syndrome) → Chronic latency (500→200 cells/μL over 8–10 years) → AIDS (<200 or AIDS-defining illness)

OI thresholds:
- <500: TB, herpes zoster, oral candidiasis
- <200 (AIDS): PCP, Toxoplasma, Cryptococcus
- <50: CMV retinitis, disseminated MAC

Diagnosis:
- Screening: 4th-gen ELISA (p24 Ag + antibody); window 18 days
- Confirmation: Western blot or NACO 3-ELISA algorithm
- EID in infants <18 months: HIV DNA PCR
- Monitoring: viral load + CD4 count

Treatment:
- HAART — TDF + 3TC + dolutegravir (India first-line); 'test and treat' policy
- Viral load target: undetectable (<1,000 copies/mL; ideally <50)

Prevention:
- Condoms, PrEP, PEP (within 72 hr), PMTCT, blood safety, ICTC free testing
- India: NACO, ICTC, free ART, NACP