Acquired immunodeficiency syndrome, more commonly known as AIDS, is the result of an infection of the human immunodeficiency virus (HIV). HIV is spread through bodily fluids such as blood and sexual secretions, but not sweat and saliva. Patients who are infected with this virus may not have any symptoms until the disease has significantly progressed.
Identification
AIDS is the final stage of a HIV infection, according to the National Institute of Allergy and Infectious Diseases (NIAID). There are two different criteria for diagnosing a person with AIDS. One is the presence of certain infections that are termed "opportunistic," meaning they only infect people with greatly weakened immune systems. The other criterion is a CD4+ T cell count of less than 200 cells per milliliter of blood, based on a laboratory test. Patients with either of these characteristics are considered to have AIDS.
HIV and T Cells
HIV is a virus that targets specific cells within the immune system called CD4+ T cells. T cells are a form of white blood cell and are needed to fight off many different kinds of infections. CD4+ cells are a subset of T cells that have a specific protein marker dubbed CD4 on their surfaces. HIV kills these cells. Initially, the body is able to produce more CD4+ T cells to compensate for the infection, but over time the body becomes depleted, leading to a severely weakened immune system.
Opportunistic Infections
Several infections are deemed opportunistic by AIDSInfoNet.org. Some of these infections almost never afflict people with healthy immune systems, such as pneumocystis pneumonia, a fungal infection that can cause a serious form of pneumonia. Patients may also develop toxoplasmosis-related encephalitis, which is the result of an organism infecting the brain. Others opportunistic infections can afflict healthy people but are more common in patients with AIDS, such as candidiasis, tuberculosis and malaria. Some organisms, such as the herpes simplex virus and the cytomegalovirus, are common infections that can cause serious complications in AIDS patients.
Other Symptoms
Aside from symptoms caused by opportunistic infections, patients with AIDS may develop a number of other symptoms including rapid weight loss, extreme fatigue and a prolonged high fever. Patients also often develop sores around the anus, mouth and genitalia as well as discolored patches on the skin. Other common symptoms include swollen lymph nodes and diarrhea lasting for one week or longer.
Treatment
Most of the treatments for HIV/AIDS hinge on slowing the disease's progression. HIV is a retrovirus, which means that it has to turn its genetic material, which is stored as RNA, into DNA--the genetic material that human cells use. Consequently, medications that combat HIV are classed as antiretroviral drugs. The treatments target various points in the HIV life cycle: some medications try to prevent the virus from entering into CD4+ T cells, whereas others block the virus' maturation and replication. Because AIDS is an advanced form of the disease, the treatment goal is to prevent fatal opportunistic infections. To this end, antibiotics are often included in treatment.
