Human Immunodeficiency Virus (HIV) Lecture Notes

This set of vocabulary flashcards covers the epidemiology, replication cycle, clinical progression, modes of transmission, and prevention strategies for HIV/AIDS based on global and U.S. 2023 data.

Human Immunodeficiency Virus (HIV)

A major global health problem recognized in the U.S. in 1981 for which no cure exists, though effective drugs are available.

WHO African Region

The most severely affected global region, accounting for 65% of people living with HIV in 2023, where nearly 1 in every 25 adults ($3.4\%$) is infected.

gp120

A protein on the surface of the HIV virus that facilitates binding to host cell receptors like CD4 and co-receptors such as CCR5 or CXCR4.

Reverse transcription

The process where viral RNA is formed into viral DNA after entering the host cell.

Integrase

An enzyme used to transport viral DNA across the nucleus and integrate it into the host DNA.

Protease

An enzyme that matures the virus by releasing individual HIV proteins from the immature virion.

Acute HIV Infection Syndrome

An initial illness occurring in about 50% of cases involving fever, rash, enlarged lymph nodes, and muscle pain, characterized by a high viral load before seroconversion.

Seroconversion

The point, usually a few weeks after infection, when HIV antibodies develop and an HIV test becomes positive.

CD4+ count

A measurement used to monitor HIV progression that indicates the state of the immune system; extremely low levels lead to opportunistic infections.

Viral load

A measurement of the amount of HIV in the blood that acts as a marker of treatment response; it is very high following initial infection and falls as antibodies develop.

AIDS-defining illnesses

A group of 28 opportunistic infections identified by the CDC that typically only develop in individuals with weakened immune systems due to HIV/AIDS.

Sexual Transmission

The most common mode of HIV transmission globally, accounting for approximately 80% of cases.

Latex condoms

A prevention method that is approximately 90% effective at reducing sexual transmission of HIV when used consistently.

Harm Reduction Programs

Programs such as syringe exchanges designed to decrease the risk of HIV by offering clean syringes in exchange for used equipment among injection drug users.

Perinatal Transmission

Also known as Mother-to-Child Transmission (MTCT), occurring in utero ($20\%$), during delivery ($60-65\%$), or through breastfeeding ($12-15\%$).

Opt-out strategy

A prenatal screening approach that has led to 85% of pregnant women getting tested for HIV.

Blood Transfusion Transmission

Considered the 'most effective way' the virus is transmitted, with a 90% infection rate for seronegative recipients of a single contaminated unit.

Healthcare seroconversion rate

A $0.4\%$ rate of infection reported among healthcare workers following percutaneous injury with HIV-contaminated surgical equipment.

HAART

Highly Active Antiretroviral Therapy; a combination of various classes of drugs used to decrease viral load, recommended for all HIV-positive patients.

Undetectable Viral Load

A viral load so low that testing cannot detect the virus; if maintained, it results in no risk of sexual transmission to an HIV-negative partner.

PrEP (Pre-exposure Prophylaxis)

The daily use of ARV medications by HIV-negative individuals at high risk to reduce the risk of infection by about 90%.

PEP (Post-exposure Prophylaxis)

An emergency 28-day course of ARV medications initiated within 72 hours of a potential HIV exposure to reduce the risk of infection by >80%.