HIV/AIDS Microbial Diseases - Vocabulary Flashcards

A set of vocabulary flashcards covering key concepts, terms, and definitions related to HIV/AIDS from the lecture notes.

HIV

Human immunodeficiency virus; a retrovirus that infects CD4 T-cells via gp120 and the CD4 receptor, using CCR5/CXCR4 coreceptors and integrating into host DNA.

Retroviridae

Virus family of enveloped ssRNA (positive-sense) viruses; HIV is a member and uses reverse transcription to integrate into the host genome.

gp120

HIV envelope glycoprotein that binds the CD4 receptor on T-cells to initiate entry.

CD4 T-cell

Helper T lymphocyte targeted by HIV; its count guides disease staging and prophylaxis decisions.

CCR5 coreceptor

Co-receptor used by many HIV strains for entry; CCR5 antagonists block this coreceptor to prevent infection.

CXCR4 coreceptor

Alternative HIV coreceptor; usage defines X4-tropic viruses and can influence disease progression.

Transmission routes

HIV spread via body fluids (blood, semen, vaginal secretions, breast milk); sexual contact, perinatal exposure, transfusions, sharing needles.

HIV epidemiology (global)

Global prevalence: hundreds of millions affected historically; by 2024 about 0.8 million living with HIV worldwide; prevalence ~0.7% among adults.

HIV epidemiology (U.S.)

About 1.2 million people living with HIV in the U.S.; ~35,000 new infections per year (rate slowing in some periods).

HIV reporting

HIV and AIDS are federally reportable to monitor spread, outbreaks, prevention, and resources.

HIV risk factors

Unprotected sex (anal sex highest risk), multiple partners, MSM, injection drug use, unsafe injections, perinatal exposures, and gaps in prevention measures.

Antiretroviral therapy (ART)

Combination drug therapy to suppress HIV replication, preserve immune function, prevent resistance, and reduce transmission.

Pre-exposure prophylaxis (PrEP)

Daily or event-based antiretroviral regimen for HIV-negative individuals to prevent infection upon exposure.

Truvada (FTC/TDF)

Emtricitabine/tenofovir disoproxil fumarate; backbone NRTI combination used in ART and PrEP.

Cabotegravir (CAB-LA)

Long-acting injectable integrase inhibitor for PrEP, administered every two months.

Immune Reconstitution Inflammatory Syndrome (IRIS)

Worsening inflammatory response after ART initiation, unmasking or worsening subclinical infections.

Acute HIV infection

Early phase with possible fever, pharyngitis, rash; high viremia and CD4 decline before latency.

Clinical latency

Asymptomatic or mild symptoms period after acute infection; virus may still replicate at low levels.

AIDS

Stage with CD4 count <200 cells/μL or AIDS-defining illnesses despite ART; increased risk of opportunistic diseases.

AIDS-defining infections (examples)

Infections indicating AIDS, e.g., Pneumocystis jirovecii pneumonia (PCP), tuberculosis, CMV infections, cryptococcosis, toxoplasmosis, MAC.

Pneumocystis jirovecii pneumonia (PCP)

Common AIDS-defining pneumonia caused by Pneumocystis; prophylaxis with TMP-SMX when indicated.

Toxoplasma gondii encephalitis

Toxoplasmosis affecting the brain; prophylaxis with TMP-SMX when CD4 is very low and Toxo IgG positive.

Mycobacterium avium complex (MAC)

Disseminated mycobacterial infection common in advanced HIV; prophylaxis with azithromycin in select cases.

Cryptococcus neoformans meningitis

Encapsulated yeast causing meningitis in AIDS; CrAg screening and treatment are key components.

Cryptosporidiosis

Protozoal GI infection causing profuse diarrhea in advanced HIV with low CD4 counts.

Cytomegalovirus (CMV) disease

Herpesvirus causing retinitis, esophagitis, colitis in AIDS; opportunistic pathogen with severe manifestations.

Kaposi’s sarcoma (HHV-8)

AIDS-defining vascular neoplasm associated with HHV-8; can appear as skin lesions and mucosal involvement.

Coccidioidomycosis

Fungal infection (endemic in SW U.S.); can cause pneumonia or disseminated disease in AIDS.

Cryptococcal antigen (CrAg) screening

Screening in HIV patients with CD4 <100 (or <200) for Cryptococcus; guides fluconazole prophylaxis and ART timing.

ART goals

Reduce HIV morbidity/mortality, lower plasma viral RNA, prevent transmission, minimize resistance, improve immune function and QoL.

Nucleic acid testing (NAT)

HIV RNA test used to detect infection earlier than antibody tests; essential for early diagnosis.

p24 antigen

HIV capsid protein detectable early in infection; used in 4th-gen assays to shorten the window period.

4th-generation HIV immunoassay

Tests that detect both HIV p24 antigen and HIV antibodies, reducing the diagnostic window.

HIV-1 vs HIV-2

HIV-1 is worldwide and more aggressive; HIV-2 is mainly in West Africa with slower progression and particular drug resistance patterns.

HIV testing algorithm (general)

Screen with 4th-gen Ag/Ab test; confirm discordant results with differentiation assay; NAT if suspicion remains.

HIV drug classes – NRTIs

Nucleoside RT inhibitors; backbone drugs (e.g., tenofovir, emtricitabine, lamivudine, abacavir, zidovudine).

HIV drug classes – NNRTIs

Non-nucleoside RT inhibitors; bind RT at a non-competitive site (e.g., efavirenz, nevirapine, doravirine).

HIV drug classes – Protease inhibitors (PIs)

Block viral protease to prevent maturation of infectious HIV; often boosted with ritonavir or cobicistat.

HIV drug classes – Integrase inhibitors (INSTIs)

Block integrase enzyme, preventing viral DNA integration (e.g., dolutegravir, bictegravir, raltegravir, elvitegravir).

HIV drug classes – Entry inhibitors

Block HIV entry: CCR5 antagonists (e.g., maraviroc) and fusion inhibitors (e.g., enfuvirtide); post-attachment inhibitors are another strategy.

Pediatric perinatal HIV management

Screening of mother, PrEP, ART during pregnancy; zidovudine to mother at delivery if viral load high; avoid breastfeeding if virus detected; prophylaxis for the newborn.

Prophylaxis by CD4 count (PCP, Toxo, MAC, Histoplasma)

PCP TMP-SMX when CD4 <200; Toxoplasma prophylaxis TMP-SMX when CD4 <200 with Toxo IgG positive; MAC prophylaxis with azithromycin when CD4 very low; Histoplasma prophylaxis with itraconazole in endemic areas.

Candida and oral hairy leukoplakia as HIV indicators

Oral thrush (Candida) and oral hairy leukoplakia are common oral manifestations during HIV disease progression.

IRIS risk factors

Low CD4 count and high HIV RNA increase the risk of IRIS after starting ART.