HIV is typically transmitted through blood, semen, vaginal fluids, rectal fluids, or breast milk.

Common transmission routes include unprotected sex, sharing needles, blood transfusions (rare), and mother-to-child during birth or breastfeeding.

HIV primarily targets CD4+ T helper cells, which are essential for activating the immune response.

The virus uses gp120 on its envelope to bind to the CD4 receptor and a co-receptor (CCR5 or CXCR4) on host cells.

Once attached, HIV fuses with the cell membrane and injects its RNA into the cell.

Inside the cell, HIV uses reverse transcriptase to convert its RNA into DNA.

The viral DNA is integrated into the host's DNA by integrase.

The host cell then produces new viral particles, which bud off and infect more CD4 cells.

As more CD4 cells are destroyed, the immune system becomes less able to respond to infections.

The body tries to replace the lost CD4 cells, but over time, it can’t keep up.

Without treatment, the number of CD4 cells falls below, the patient develops opportunistic infections or certain cancers.

This stage is defined as AIDS.

At this point, the immune system is severely compromised, and even minor infections can be life-threatening.

Flu-like symptoms that may last a few days to weeks:

• Fever

• Sore throat

• Swollen lymph nodes

• Rash

• Muscle aches

• Headache

• Fatigue

High viral load (very contagious)

Often misdiagnosed as a cold or flu

The virus is still active but reproduces at low levels

May last 5–10 years or more without treatment

Often no symptoms, but the virus is still damaging the immune system

Some may experience:

• Swollen lymph nodes

• Mild infections (oral thrush, shingles)

• Weight loss or fatigue

CD4 count begins to drop gradually

CD4 count < 200 cells/mm³ or presence of AIDS-defining illnesses

Immune system is severely weakened

Symptoms and conditions include:

• Opportunistic infections:

  • Pneumocystis pneumonia (PCP)

  • Tuberculosis (TB)

  • Toxoplasmosis

  • Candidiasis (thrush)

• Cancers:

  • Kaposi’s sarcoma

  • Non-Hodgkin’s lymphoma

  • Cervical cancer

• Neurological problems:

  • HIV-associated dementia

  • Confusion, memory loss

• Wasting syndrome:

  • Severe weight loss

  • Muscle wasting

  • Chronic diarrhea and fatigue

• Prolonged fever and night sweats

HIV is a retrovirus (from the Lentivirus genus), meaning it utilizes RNA as its specified genetic material and requires reverse transcriptase to make DNA from RNA.

Attacks the body's immune system by distinctly targeting CD4+ T cells.

As the virus replicates, the immune system will weaken, leaving the body in a vulnerable, compromised state, more to susceptible to infection and illness.

Caused by Human Immunodeficiency Virus (HIV)

• Two types:

  • HIV-1 - most common worldwide

  • HIV-2 - less common, more prevalent in West Africa

Prevalence:

• Over 1.2 million people in the U.S. are living with HIV.

Undiagnosed Rate:

• About 13% of those infected are unaware of their status.

Incidence:

• In 2022, there were about 32,000 new HIV diagnoses.

Demographics:

• Highest risk groups: Black/African American and Latino communities, men who have sex with men (MSM), and people aged 25–34.

• Regional hot spots: The Southern U.S. has the highest rates of new infections.

Texas has one of the highest HIV infection rates in the U.S., especially in cities like Houston and Dallas.

Prevalence & Incidence:

• In 2022, Texas had over 90,000 people living with HIV, with nearly 4,000 new cases that year.

Distribution:

• High HIV demographics include: Majorly Hispanic (30% in women, 41% in men) and Black (48% in women, 31% in men) ethic groups, with 60% of infected individuals being under the age of 35.