A
- AHCC
- Active Hexose Correlated Compound — a mushroom-derived immune supplement studied for accelerating HPV clearance. Read more →
- Acyclovir
- The original first-line antiviral for herpes simplex virus. Generic, cheap, but requires 3-5 doses per day. Read more →
- AIDS
- Acquired Immunodeficiency Syndrome — the late-stage condition that develops when HIV is left untreated for years. Preventable with modern ART. Read more →
- Antiretroviral therapy (ART)(ART, HAART)
- Modern HIV treatment regimen — typically a once-daily combination pill that suppresses viral replication and prevents progression to AIDS. Read more →
- Apretude
- Brand name for cabotegravir long-acting injectable PrEP. Every-2-month injection in the buttock; FDA-approved 2021. Read more →
- Asymptomatic shedding
- Periods when a virus (especially HSV) is present and contagious on skin or mucosa without any visible lesion. Most herpes transmission happens during this window. Read more →
- Azithromycin
- Antibiotic used for chlamydia, gonorrhea, and some respiratory infections. Single-dose convenience; reserved for specific scenarios in current chlamydia treatment. Read more →
C
- Cantharidin
- Topical agent used in dermatology clinics to remove molluscum contagiosum lesions. FDA-approved as Ycanth in 2023. Read more →
- CD4 count
- A measure of the immune system, specifically the CD4 helper T-cells targeted by HIV. Below 200 cells/mm³ defines AIDS. Read more →
- Chancre
- The painless ulcer that appears in primary syphilis at the site of infection. Heals on its own but the bacteria persist. Read more →
- Chlamydia
- A common bacterial STI caused by Chlamydia trachomatis. Usually asymptomatic; curable with antibiotics; can cause infertility if untreated. Read more →
- Cold sore
- A lesion caused by HSV-1 (oral herpes), usually on or around the lips. Triggered by stress, illness, UV exposure. Read more →
- Cryotherapy
- Freezing skin lesions (warts, molluscum) with liquid nitrogen. First-line in-clinic treatment for many STI-related skin findings. Read more →
D
- Doxycycline
- Tetracycline-class antibiotic. Current first-line treatment for chlamydia. Not used in pregnancy. Read more →
F
- Famciclovir
- Antiviral for herpes simplex virus. Similar efficacy and dosing to valacyclovir; less commonly prescribed. Read more →
G
- Gardasil 9
- The HPV vaccine, covering 9 strains responsible for most HPV-associated cancers and genital warts. FDA-approved to age 45. Read more →
- Genital warts
- Soft, cauliflower-shaped growths caused by low-risk HPV strains (mostly HPV-6 and HPV-11). Painless. Removable via several methods. Read more →
- Gonorrhea
- Bacterial STI caused by Neisseria gonorrhoeae. Curable with antibiotics; growing antibiotic resistance is a public-health concern.
H
- Hepatitis B
- Viral liver infection transmitted sexually or through blood. Preventable with vaccine; chronic infection treatable with antivirals.
- Hepatitis C
- Viral liver infection transmitted mostly through blood. Now curable in 95%+ of cases with 8-12 weeks of direct-acting antivirals.
- Herpes simplex virus (HSV)(HSV-1, HSV-2)
- Family of two viruses (HSV-1 and HSV-2) that cause recurrent oral or genital lesions. Lifelong; no cure currently. Managed with antivirals. Read more →
- HIV
- Human Immunodeficiency Virus. Attacks the immune system. Modern treatment makes it a manageable chronic condition with near-normal lifespan. Read more →
- HPV
- Human Papillomavirus. Most common STI globally. Most strains clear naturally; high-risk strains cause cervical and other cancers. Vaccine highly effective. Read more →
I
- IgG / IgM
- Antibody types measured in blood tests. IgG develops in established infection. IgM develops earlier but is not reliable for HSV diagnosis. Read more →
- Imiquimod
- Topical immune-stimulating cream (Aldara) used for genital warts and some skin cancers. Read more →
L
- Lenacapavir
- Twice-yearly subcutaneous injection. FDA-approved 2024 for HIV PrEP after the PURPOSE trials showed near-100% efficacy. Read more →
M
- Molluscum contagiosum
- A pox virus causing small, dome-shaped pearly bumps with a central dimple. Self-limiting over 6-18 months. Read more →
N
- NAAT
- Nucleic Acid Amplification Test. Highly sensitive direct-detection test used for chlamydia, gonorrhea, trichomoniasis. Gold standard. Read more →
- Neurosyphilis
- When untreated syphilis invades the central nervous system. Can occur at any stage but most common in late untreated disease. Read more →
P
- PEP
- Post-Exposure Prophylaxis. A 28-day course of HIV antiretroviral medication started within 72 hours of a possible HIV exposure. Read more →
- PID
- Pelvic Inflammatory Disease. Complication of untreated chlamydia or gonorrhea; leads to infertility and ectopic pregnancy. Read more →
- PrEP
- Pre-Exposure Prophylaxis. Medication taken by HIV-negative people to prevent HIV — daily pill (Truvada, Descovy) or injection (Apretude, Lenacapavir). Read more →
- Pritelivir
- New-mechanism antiviral for HSV. Helicase-primase inhibitor; active against acyclovir-resistant herpes. Late-stage trials. Read more →
R
- RPR / VDRL
- Non-treponemal blood tests used to screen for syphilis. Combined with a treponemal confirmatory test (TP-PA, FTA-ABS) for diagnosis. Read more →
S
- Sterilizing cure
- Complete removal of a virus from the body, with no detectable DNA in any cells. The hardest goal; the CRISPR-style approach for HIV and HSV. Read more →
- STI / STD
- Sexually Transmitted Infection / Disease. The terms are interchangeable; STI is preferred in modern clinical use because most STIs are infections without active disease for most of their course. Read more →
- Suppressive therapy
- Daily antiviral medication (typically valacyclovir 500 mg or 1 g) taken to reduce herpes outbreak frequency and transmission risk. Read more →
- Syphilis
- Bacterial STI caused by Treponema pallidum. Four stages if untreated. Fully curable with penicillin at any stage. Read more →
T
- Trichomoniasis
- Common parasitic STI caused by Trichomonas vaginalis. Curable with metronidazole or tinidazole.
U
- U=U
- Undetectable equals Untransmittable. A person living with HIV whose viral load is suppressed by ART cannot transmit HIV sexually. Read more →
V
- Valacyclovir (Valtrex)
- Modern first-line antiviral for herpes. Prodrug of acyclovir with better bioavailability — needs only 1-2 doses per day. Read more →
- Viral load
- The amount of virus measurable in blood. Reported as copies per milliliter. Undetectable viral load is the goal of HIV treatment. Read more →
W
- Western blot
- Gold-standard confirmatory antibody test. Used for HSV when low-positive IgG results need disambiguation. Available through University of Washington. Read more →
Missing a term?
Email [email protected] — we add definitions on request. This page is updated as we get reader questions.
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