HIV
HIV (human deficiency virus) is an infectious disease that leads to a syndrome known as AIDS (acquired immunodeficiency syndrome), severely affecting the body's adaptive immune system.
Phases
It is a progressive disease that consists of 3 phases:
- Infection and acute HIV syndrome (acute HIV, days to weeks). Presents with mononucleosis-like symptoms that start several weeks after infection, and last for several days or weeks.
- Asymtomatic phase (chronic HIV, 4-7 years). Progressive decrease in CD4 count (down to 500/mm^3).
- Symptomatic phase (pre-AIDS, 1-3 years). May present with nonspecific symptoms (weight-loss, night sweats, diarrhea), and first evidence of immunodeficiency:
- Vaginal candidiasis
- Herpes simplex and zoster
- Kaposi sarcoma
- AIDS. When the CD4 count is low enough (<200/mm^3), sever immunodeficiency leads to further opportunistic infections and tumors.
- Pneumocystis pneumonia (most common)
- Oral candidiasis
- Pneumocystosis
- Toxoplasmosis
- Cryptococcosis
- Cryptosporidiosis
- Histoplasmosis
- Disseminated mycobacterium avium complex infection
- CMV
- CNS lymphoma
Characteristics
- Most commonly due to HIV type 1.
- The virus targets CD4