Among people living with HIV (PLHIV) in India, the most common opportunistic infection (OI) at the time of AIDS diagnosis (CD4 count <200 cells/μL) is which of the following?

Explanation

## Most Common Opportunistic Infection in Indian HIV/AIDS Patients **Key Point:** Tuberculosis (TB) is the most common opportunistic infection in PLHIV in India, occurring in 40–60% of patients with CD4 <200 cells/μL, and is the leading cause of morbidity and mortality in this population. ### Epidemiological Basis India carries the world's largest TB burden (~27% of global TB cases) and the highest TB-HIV co-infection rate. The convergence of these two epidemics creates a unique epidemiological landscape: 1. **High TB prevalence in the general population** — TB incidence in India is ~199 per 100,000, providing ample opportunity for TB-HIV co-infection. 2. **Immunological vulnerability** — CD4 <200 cells/μL renders PLHIV exquisitely susceptible to reactivation TB and primary progressive TB. 3. **Bidirectional acceleration** — TB accelerates HIV progression and increases viral load; HIV accelerates TB progression and increases TB mortality. ### Comparative Frequency of OIs in Indian PLHIV (CD4 <200 cells/μL) | Opportunistic Infection | Frequency | Geographic/Population Notes | |------------------------|-----------|----------------------------| | **Tuberculosis** | 40–60% | Most common; all forms (pulmonary, extrapulmonary) | | **Oral candidiasis** | 30–40% | Common but less severe than systemic OIs | | **Cryptococcal meningitis** | 5–10% | Significant cause of mortality; more common in advanced disease | | **Cytomegalovirus (CMV) retinitis** | 1–3% | Rare in India; more common in resource-rich settings | | **Pneumocystis jirovecii pneumonia (PCP)** | <1% | Extremely rare in India; more common in Western countries | | **Toxoplasmosis** | 1–2% | Rare; requires specific serological risk factors | **High-Yield:** TB-HIV co-infection is a defining feature of the Indian HIV epidemic. Every PLHIV with CD4 <200 should be screened for TB using clinical evaluation, chest X-ray, and TB-LAMP (or GeneXpert MTB/RIF). TB preventive therapy (TPT) with isoniazid is recommended for all PLHIV regardless of CD4 count. **Mnemonic:** **CHOP** — Common OIs in India's HIV epidemic: - **C**andidiasis (oral) - **H**erpes simplex virus (HSV) - **O**pportunistic infections (TB dominates) - **P**neumonia (bacterial, atypical) But **TB** is the undisputed #1. ### Why TB Dominates in India ```mermaid flowchart TD A[PLHIV with CD4 &lt; 200]:::outcome A --> B{TB exposure/reactivation?}:::decision B -->|Yes: High TB prevalence in India| C[TB-HIV co-infection]:::urgent B -->|No: Rare TB exposure| D[Other OIs: Cryptococcal meningitis, Candidiasis]:::outcome C --> E[40-60% of PLHIV develop TB]:::action D --> F[&lt;10% of PLHIV develop these]:::action ``` **Clinical Pearl:** A PLHIV presenting with fever, cough, and CD4 <200 should be assumed to have TB until proven otherwise. Chest X-ray may show atypical patterns (middle/lower lobe infiltrates, minimal cavitation) due to profound immunosuppression. TB-LAMP or GeneXpert MTB/RIF should be performed urgently. **Warning:** PCP (Pneumocystis jirovecii pneumonia) is a classic board answer in Western HIV epidemiology but is exceptionally rare in India (<1%). Do not confuse the Western paradigm with Indian epidemiology. Bacterial pneumonia and TB are far more common causes of respiratory disease in Indian PLHIV. [cite:Park 26e Ch 5; Harrison 21e Ch 197]