Not inherited in the genes from ones parents but coming from others in the environment.

Resistance resulting from previous exposure to an infectious agent or antigen may be active or passive. Passive immunity can be acquired from the transfer of antibodies from another person or from an animal, either naturally-as from mother to foetus or to the newborn via breast milk-or by intentional inoculation (vaccination).

The period of rapid viral replication immediately following exposure to HIV. An estimated 80 to 90 percent of individuals with primary HIV infection develop an acute syndrome characterized by flu-like symptoms of fever, malaise, lymphadenopathy, pharyngitis, headache, myalgia, and sometimes rash. Following primary infection, sero-conversion and a broad HIV-1 specific immune response occur, usually within an average of 3 weeks after transmission of HIV. It was previously thought that HIV was relatively dormant during this phase. However, it is now known that during the time of primary infection, high levels of plasma HIV RNA can be documented.

Any disease involving or causing enlargement of glandular tissues, especially one involving the lymph nodes.

The extent to which the patient continues the agreed-upon mode of treatment or intervention as prescribed.

Acronym for Acquired Immune Deficiency Syndrome. This means the body loses the ability to fight against infections because the immune system is weakened by the virus. AIDS is the late stage of HIV disease.

Specific diseases which in the presence of HIV infection indicate the clinical development of AIDS.

(HIV-associated dementia or HAD.) A degenerative neurological condition attributed to HIV infection, characterized by a group of clinical presentations including loss of coordination, mood swings, loss of inhibitions, and widespread cognitive dysfunction. It is the most common central nervous system complication of HIV infection. Characteristically, it manifests itself after the patient develops major opportunistic infections or AIDS-related cancers. However, patients can also have this syndrome before these major systemic complications occur. The cause of ADC has not been determined exactly, but it may result from HIV infection of cells or inflammatory reactions to such infections.

The involuntary weight loss of 10 percent of baseline body weight plus either chronic diarrhoea (two loose stools per day for more than 30 days) or chronic weakness and documented fever (for 30 days or more, intermittent or constant) in the absence of a concurrent illness or condition other than HIV infection that would explain the findings.

Several cancers are more common or more aggressive in persons living with HIV. These malignancies include certain types of immune system cancers known as lymphomas, Kaposi's Sarcoma, and ano-genital cancers that primarily affect the anus and the cervix. HIV, or the immune suppression it induces, appears to play a role in the development of these cancers.

Occurring before birth.

A survey of HIV prevalence in pregnant women attending antenatal clinics. In South Africa, these surveys have been conducted every year since 1990, in public health facilities.

Molecules in the blood or other body fluids that tag, destroy, or neutralize bacteria, viruses, or other harmful toxins (antigens). They are members of a class of proteins known as immunoglobulins, which are produced and secreted by B-lymphocytes in response to stimulation by antigens. An antibody is specific to an antigen.

Substances used to kill or inhibit the multiplication of retroviruses such as HIV.

Therapy which prevents HIV from replicating, thus bringing about a reduction in the HIV viral load and a restoration of the CD4+ count. Early antiretroviral regimens consisted of only one or two drugs (monotherapy and dual therapy respectively), but since the development of new classes of drugs in the mid-1990s, more effective regimens of three or more drugs (highly active antiretroviral treatment, or HAART) have been introduced.

Artificial rupture of membranes during childbirth (labour) by using a special instrument. This procedure is carried out if the membranes have not ruptured spontaneously during labour.

A mathematical model developed by the Actuarial Society of South Africa (ASSA) to simulate the spread of HIV in South Africa, and the demographic impact of AIDS.

A mathematical model developed by the Actuarial Society of South Africa (ASSA) to assess the potential impact of HIV/AIDS on workforce populations. The model can also be used to estimate the financial impact of AIDS on businesses, e.g. through increased employee benefit costs and reduced productivity.

Not experiencing any signs of infection.