MI3.10-13 | Blood & Tissue Parasites and HIV/AIDS — Glossary

HIV screening assay detecting both p24 antigen and HIV antibodies (IgM/IgG for HIV-1 and HIV-2); window period ~18 days; >99.5% sensitivity

Advanced HIV disease defined by CD4+ <200 cells/μL OR occurrence of an AIDS-defining opportunistic infection or malignancy

Ring form of P. falciparum lying flat against the inner RBC membrane edge — a hallmark of P. falciparum on smear

First-line treatment for uncomplicated P. falciparum malaria — artemether-lumefantrine or artesunate-amodiaquine; IV artesunate for severe malaria

Massive intravascular haemolysis in P. falciparum malaria → haemoglobinuria (dark/black urine) → acute tubular necrosis; rare, associated with quinine use in G6PD-deficient patients

Chemokine co-receptor used by macrophage-tropic HIV-1 strains for cell entry; CCR5 delta-32 homozygous mutation confers resistance to HIV; targeted by maraviroc

T-helper cell; primary target of HIV; normal count 500–1,500 cells/μL; count guides OI prophylaxis and defines AIDS (<200 cells/μL)

Life-threatening complication of P. falciparum — unarousable coma from microvasculature sequestration in the brain; treated with IV artesunate

Latex agglutination or lateral flow assay detecting cryptococcal polysaccharide antigen in CSF or serum; near 100% sensitive in active cryptococcal meningitis

Encapsulated yeast causing subacute meningitis at CD4 <100; diagnosed by India ink stain + CrAg test; treated with amphotericin B + flucytosine

Chemokine co-receptor used by T-cell-tropic HIV-1 strains; becomes predominant in late HIV infection

Integrase strand transfer inhibitor (INSTI); part of India's first-line ART regimen (TDF + 3TC + DTG); high barrier to resistance, once-daily, well-tolerated

HIV DNA PCR used to detect HIV infection in infants <18 months born to HIV-positive mothers; maternal antibodies make ELISA unreliable until 18 months

Gross lymphoedema of lower limbs, scrotum, or breast caused by adult filarial worms blocking lymphatics; irreversible in advanced cases

X-linked enzymatic defect causing haemolysis when exposed to oxidant drugs (primaquine, dapsone) — must be tested before radical cure with primaquine

Sexual form of Plasmodium in peripheral blood; ingested by Anopheles to continue the sexual (sporogonic) cycle in the mosquito

Surface glycoprotein of HIV envelope; binds CD4 receptor and CCR5 or CXCR4 co-receptor to initiate viral entry into target cells

Transmembrane HIV glycoprotein; mediates fusion of viral and host cell membranes after gp120-receptor binding

Combination of ≥3 antiretroviral drugs from ≥2 classes targeting HIV at multiple steps; suppresses viral load to undetectable levels and restores immunity

Lentivirus (retrovirus) causing AIDS; two types — HIV-1 (pandemic) and HIV-2 (West Africa); targets CD4+ T lymphocytes via gp120-CD4-CCR5/CXCR4 interaction

Dormant liver form of P. vivax and P. ovale; reactivates months to years later causing relapse; eliminated only by primaquine

Negative staining technique for CSF examination; encapsulated Cryptococcus neoformans appears as clear halo (capsule) against dark background

HIV enzyme that inserts proviral DNA into the host cell chromosome, establishing latent infection; target for integrase inhibitors (e.g., dolutegravir)

Paradoxical clinical worsening of a pre-existing OI after ART initiation due to restoration of pathogen-specific immune responses; occurs 4–8 weeks after ART start

Amastigote form of Leishmania — oval, 2–4 μm, with nucleus and rod-shaped kinetoplast; found intracellularly in macrophages in tissue smears

Protozoan causing visceral leishmaniasis (kala-azar); amastigotes reside in macrophages of bone marrow, liver, spleen; transmitted by Phlebotomus sandfly

Coarse, irregular stippling in P. falciparum-infected RBCs; less visible than Schüffner's dots; related to knob formation

Asexual progeny released when a schizont-infected RBC ruptures; invades new RBCs to continue the erythrocytic cycle

Early larval stage of filarial worms found in peripheral blood (or lymphatics); nocturnal periodicity — peak concentration in blood at 10 PM–2 AM

Apex body under the Ministry of Health & Family Welfare, India, responsible for the national AIDS control programme, ICTC, ART centres, and NACP

Phenomenon where microfilariae of Wuchereria bancrofti accumulate in peripheral blood between 10 PM–2 AM, corresponding to Culex mosquito peak biting activity

Infection by organisms that rarely cause disease in immunocompetent hosts but exploit immune suppression; CD4 count predicts which OI is likely

28-day course of ART (TDF + 3TC + DTG) started within 72 hours of HIV exposure (sexual, occupational, or other); reduces transmission risk by ~80% if taken correctly

P. falciparum erythrocyte membrane protein 1 — expressed on surface of infected RBCs; mediates cytoadherence to endothelium causing sequestration in cerebral malaria

Vector of Leishmania donovani in India — nocturnal, small (2 mm), breeds in moist sandy soil; bites at floor level; controlled by indoor residual spraying

Genus of apicomplexan protozoan parasites causing malaria; four species infect humans: P. falciparum, P. vivax, P. ovale, P. malariae

Prevention of Mother-to-Child Transmission — universal antenatal HIV testing, ART for HIV-positive pregnant women, infant NVP prophylaxis, EID testing; reduces MTCT from 25–45% to <2%

Fungus (formerly classified as protozoan) causing PCP — the commonest AIDS-defining OI in non-India settings; interstitial pneumonia at CD4 <200; diagnosed by GMS stain of BAL

Daily TDF-emtricitabine taken by HIV-negative high-risk individuals to prevent acquisition of HIV; >90% effective with adherence

HIV genome integrated into the host chromosome by integrase; persists for the life of the cell — the latent reservoir not eliminated by current ART

Recurrence of P. falciparum or P. malariae malaria from persistent low-level erythrocytic parasitaemia — not from liver forms; due to incomplete treatment

Recurrence of P. vivax or P. ovale malaria from hypnozoite reactivation — can occur months to years after primary infection; prevented by primaquine

HIV enzyme that converts the RNA genome into double-stranded DNA (proviral DNA); error-prone — generates mutations that drive drug resistance

Rapid immunochromatographic strip test detecting anti-rK39 IgG antibodies in kala-azar; >95% sensitive/specific in the Indian subcontinent; field-applicable

Asexual multiplication by multiple fission — nucleus divides repeatedly before cytoplasm divides, producing multiple progeny (merozoites or schizonts)

Fine eosinophilic stippling of infected RBCs seen in P. vivax and P. ovale; represents parasite-modified RBC membrane caveolae

Infective form of Plasmodium injected by Anopheles mosquito; travels to liver to initiate exo-erythrocytic schizogony

Scientific consensus that a person living with HIV on effective ART with undetectable viral load (<200 copies/mL) cannot sexually transmit HIV

Interval between HIV infection and detectable antibodies/antigen on laboratory tests; 18 days for 4th-generation ELISA, 10–12 days for NAT/PCR

Filarial nematode causing lymphatic filariasis; microfilariae are sheathed with no nuclei in tail tip; transmitted by Culex quinquefasciatus mosquito