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HIV-1

HIV/AIDS OVERVIEW

HIV-1 stands for Human Immunodeficiency Virus 1, the most common type of HIV worldwide, which is a retrovirus that infects and destroys CD4 T-lymphocytes, gradually impairing the immune system and increasing the risk of opportunistic infections and cancer. The virus originated from SIVcpz (Simian Immunodeficiency Virus of chimpanzees) and is responsible for the global AIDS pandemic. Early infection can present with flu-like symptoms, including fever, headache, muscle aches, rash, and swollen lymph nodes, though some people may experience no symptoms at all.

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What is HIV-1?

  • Type of Virus: HIV-1 is a lentivirus, a type of retrovirus.
  • Impact on the Immune System: It primarily targets and destroys CD4 T-lymphocytes, crucial cells for cell-mediated immunity.
  • Origin: HIV-1 group M, the main cause of the AIDS pandemic, originated from the cross-species transmission of SIVcpz from chimpanzees in southeastern Cameroon approximately a century ago.

Symptoms of HIV-1 Infection

Symptoms vary depending on the stage of the infection. 

  • Acute (Primary) Infection: Some individuals develop a flu-like illness within 2 to 4 weeks of contracting the virus.
  • Common Symptoms: Fever, headache, muscle and joint pain, rash, sore throat, swollen lymph nodes, diarrhea, and weight loss.
  • Asymptomatic Stage: Some people experience no symptoms during this initial stage.

1. Acute HIV infection (2–4 weeks after exposure):

  • Fever

  • Sore throat

  • Rash

  • Swollen lymph nodes

  • Muscle/joint pain

  • Resembles flu or mononucleosis

2. Chronic HIV infection (clinical latency):

  • Often no symptoms for years

  • Virus keeps multiplying at low levels

3. AIDS (advanced stage):

  • CD4 count <200 cells/µL

  • Severe infections (opportunistic infections like TB, pneumonia, fungal infections)

  • Weight loss, night sweats, chronic diarrhea

  • Certain cancers (Kaposi’s sarcoma, lymphoma)

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Consequences of Untreated HIV-1

  • Impaired Immunity: Continued destruction of CD4 cells leads to a weakened immune system.
  • Increased Risk of Infections: A compromised immune system increases the risk of opportunistic infections.
  • Cancer Risk: The risk of developing certain cancers is also elevated.

Transmission of HIV-1

HIV-1 spreads when infected body fluids enter the bloodstream.

  • Unprotected sex (vaginal, anal, oral in rare cases).

  • Sharing needles/syringes.

  • Mother-to-child (during pregnancy, childbirth, or breastfeeding).

  • Blood transfusions (rare today due to screening).

HIV is not spread by hugging, shaking hands, sharing food, or mosquito bites.

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Diagnosis

  • Antibody/antigen tests (ELISA, rapid tests)

  • PCR test (detects viral RNA)

  • CD4 count (measures immune strength)

  • Viral load test (how much virus in blood)

Treatment of HIV-1

No cure exists yet, but ART (Antiretroviral Therapy) controls HIV.

  • Combination of 3 or more drugs from different classes.

  • Main drug classes:

    • NRTIs (Nucleoside Reverse Transcriptase Inhibitors)

    • NNRTIs (Non-Nucleoside RT Inhibitors)

    • PIs (Protease Inhibitors)

    • INSTIs (Integrase Strand Transfer Inhibitors)

    • Entry/Fusion inhibitors

✅ ART reduces viral load to undetectable levels → person can live a long, healthy life.
✅ “Undetectable = Untransmittable (U=U)” → If viral load is undetectable, HIV cannot be sexually transmitted.

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Prevention of HIV-1

  • Consistent condom use

  • Pre-exposure prophylaxis (PrEP) → daily pill for high-risk individuals

  • Post-exposure prophylaxis (PEP) → emergency treatment within 72 hours of exposure

  • Safe needle programs

  • Regular HIV testing

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