User:Peter A. Lipson/aids

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Acquired Immune Deficiency Syndrome (usually referred to as AIDS) is a collection of diseases and symptoms caused by long-term infection with the Human Immunodeficiency Virus.

Definition

According to the CDC's 1993 guidelines, [1][2]as follows: HIV infection plus any of the following:

  • CD4 count less than 200 or
  • CD4 percentage less than 14% of total lymphocytes or
  • Any of the following illnesses: pulmonary TB, recurrent pneumonia, invasive cervical cancer.
  • Expanded definition including 23 clinical conditions published elsewhere[3]

The World Health Organization uses a different staging method for HIV disease. [4]

History [5]

The illness was first recognized in the early 1980s [6] as gay men presented to their doctors with a rare lung disease called Pneumocystis carinii pneumonia (PCP). Early on, the syndrome took on a variety of names, including "Gay-related immune deficiency (GRID)"citation needed. The Centers for Disease Control noticed an increase in the requests for the drugs needed to treat this illness and launched an epidemiologic investigation. Although the first cases of the disease probably go back to the 1950s, the epidemic was not recognized until the early 1980s. The early epidemic occurred in two main branches; in the US and other developed countries, and in sub-Saharan Africa. In the US, the early epidemic was primarily spread by homosexual sex, intravenous drug use, and blood transfusions. In Africa, transmission was almost exclusively by heterosexual sex. Currently, most new infections worldwide are spread by heterosexual sex.

Natural History

After infection with HIV, the virus quickly replicates in lymphatic tissue and travels through the blood to infect most areas of the body. The largest consequence of this is the "hijacking" of certain immune cells, especially so-called T-Helper, or CD-4, cells. Early in the infection, the immune system holds the infection at bay, often causing "Acute Retroviral Syndrome", a flu-like illness. Patients often have swollen lymph nodes. After approximately 8-10 years of infection, the immune system begins to lose its battle. This is primarily seen in the loss of numbers of CD4 cells, however the changes are somewhat more complex. When the CD4 cell level drops low enough, AIDS becomes apparent. The first symptoms of the illness are generally night sweats, weight loss, and oral thrush.

Opportunistic Infections (OIs)

The hallmark of AIDS is the appearance of opportunistic infections, meaning infections with organisms that do not usually cause human disease, unless given the right "opportunity". This opportunity is the reduction in cell-mediated immunity, first seen in patients with certain cancers or on anti-rejection drugs for organ transplantation. These infections include:

  • Pneumocystis jiroveci, previously Pneumocystis carinii
  • Candida albicans (the cause of thrush and vaginal yeast infections)
  • Staphylococcus aureus (primarily causes skin infections)
  • Toxoplasma gondii
  • Cytomegalovirus
  • Streptococcus pneumoniae (the primary cause of pneumonia in AIDS patients)
  • Mycobacterium tuberculosis (TB)
  • Mycobacterium avium complex (atypical mycobacterium)
  • Cryptococcus neoformans (a cause of meningitis)
  • Epstein Barr virus (leads to a type of lymphoma)
  • Human herpesvirus-8 (causes Kaposi's sarcoma)


Dissent

Among the worlds medical professionals and biologists, there is complete agreement that HIV causes AIDS. In this, Koch's postulates have been clearly fulfilled, and basic science research has shown the same. Specific drugs have been developed that treat HIV infection and AIDS, helping show the causal relationship. That being said, there is a vocal minority of people, including some scientists, who do not believe that HIV causes AIDS. Foremost among these is Dr. Peter Duesberg. Details about these "re-thinkers" and their arguments can be found at several websites, but not in any reliable peer-reviewed journals:

http://www.reviewingaids.org/awiki/index.php/Main_Page


Notes

  1. http://www.cdc.gov
  2. http://www.merckmedicus.com/ppdocs/us/hcp/content/merck/hiv/hivaids/aidsdefi.htmAIDS is defined
  3. http://www.cdc.gov/MMWR/preview/mmwrhtml/00018871.htm
  4. http://www.aids-ed.org/aetc/aetc?page=cm-105_disease
  5. New England Journal of Medicine, Volume 344:1764-1772 June 7, 2001 Number 23
  6. Pneumocystis pneumonia -- Los Angeles. MMWR Morb Mortal Wkly Rep 1981;30:250-252)