The Biology of the Stages of HIV Disease

(updated for Winter Term 2004)

Stages of HIV Disease

  • Different classifications used
  • We will use 3-stages
    • acute infection
    • asymptomatic
    • late stage
  • Basis for different classifications
    • clinical, biological, testable, etc.

Time course of the stages

  • Rapid progression occurs (about 10%)
    • AIDS within 2-3 years after infection
  • “Normal” progression
    • AIDS within 5-10 years after infection
  • Slow progression (10-20%)
    • NO AIDS even 10-20 years after infection

Acute phase

  • Symptoms resembe Flu or mononucleosis
  • No antibodies made yet
  • Typical symptoms:
  • fever, sore throat, headache, swollen glands, sometimes a rash, vomiting, diarrhea, or thrush.
  • Usually lasts 2-8 weeks

Other features of Acute Phase

  • Highly infectious by normal routes
  • Tests negative by antibody test
  • Lymph nodes seeded with infected cells

Asymptomatic stage

  • Lasts for years
  • Most definitely NOT a quiet time for the virus
  • 1-10 billion new virus made every day
  • many T-cells destroyed every day
  • lots of mutants accumulating, lots of T-cells with new specificities accumulation too.

Other features of This Stage

  • Antibodies detectable
  • Still infectious, but maybe less so
  • Generally good health

Late stage: pre-AIDS

  • Beginning of late stage
    • weight loss, night sweats, fever, malaise, loss of appetite, diarrhea, swollen glands
  • Destruction of lymph glands (breakdown of the network that traps everything)
  • Drop in T-cell count
    • thrush, bacterial infections, fungal and viral infections

AIDS-Related Complex

  • An old term for the beginning of the late (symptomatic) stage of HIV Disease

Late Stage: AIDS

  • New definition
    • not dependent on health
    • T-cell count of less than 200 per milliliter of blood
    • HIV positive test
  • Old definition
    • two diseases from a list of about 20 (including PCP, Kaposi’s sarcoma, cryptosporidium, etc.
  • A person has AIDS if either definition applies

Viral Load

  • Auring acute phase, a huge bloom of free virus
  • During asymptomatic stage, much lower, but constant
  • As T-cells disappear and lymph nodes degrade, another (terminal) bloom of virus and full progression to AIDS

Pediatric AIDS

  • Progression is much more rapid
    • clinical symptoms usually within 6 monhs
    • death usually within 2 years
    • drugs are extending that, but…
  • Spectrum of diseases are different in Pediatric AIDS
    • more bacterial diseases, more bacterial and viral pneumonia, little KS or PCP

Some of the “non-AIDS” Diseases that come with HIV Disease (T-cells still over 200)

  • Bacterial infections and skin infections
  • Shingles
  • thrush
  • severe athlete’s foot

Some of the AIDS related diseases (T cells under 200)

  • Tuberculosis (disseminated)
  • Pneumocystis carinii pneumonia
  • Cryptococcal meningitis
  • Toxoplasmosis
  • Cryptosporidium infection
  • Cytomegalovirus infections
  • Kaposi’s sarcoma