Terminology
Acute Infection
Any infection that begins suddenly, with intense or severe symptoms, is called acute (or primary). If the illness lasts more than a couple of weeks, it is called chronic.
Adherence
Adherence measures how faithfully a person takes all antiretroviral medications at the right time. Poor adherence is one of the main reasons antiretroviral combinations fail.
AIDS
Acquired Immunodeficiency Syndrome. A disease caused by a retrovirus, HIV (human immunodeficiency virus), and characterized by failure of the immune system to protect against infections and certain cancers.
Antibody
A substance in the blood formed in response to invading disease agents such as viruses, fungi, bacteria, and parasites. Usually antibodies defend the body against invading disease agents, however, the HIV antibody does not give such protection.
Antigen
An invading substance that may be the target of antibodies.
Antiretroviral treatment
A treatment that may prevent HIV from further damaging the immune system by blocking or hampering the reproduction of the HIV virus.
Antiviral
A substance that stops or suppresses the reproduction of a virus.
ATHENA
AIDS Therapy Evaluation in the Netherlands project (ATHENA).
B cell
A white blood cell that makes antibodies against disease agents in the body.
cART
Combination antiretroviral treatment.
CD4 (T4) cell
CD4+ T-lymfocyte, or T4-cell or T-helper cell. A white blood cell that plays a vital role within the immune system and can be infected by the HIV virus. In the course of the HIV infection the number of CD4 cells may drop from normal levels (+ 500 per mm³) to dangerously low levels (fewer than 200 CD4 cells per mm3 of blood).
CIb
Centre for Infectious Disease Control Netherlands (www.rivm.nl/cib).
DAD Study
The international collaboration on Data Collection on Adverse events of Anti-HIV Drugs.
DNA
Deoxyribonucleic acid. A complex protein that carries genetic information. HIV can insert itself into the DNA molecules inside human cells and establish dormant infection.
GGD
Dutch municipal health service (www.ggd.nl).
HAART
Highly Active Antiretroviral Therapy, also known as combination antiretroviral therapy (cART).
Hepatitis B
A viral infection (HBV) that affects the liver and is transmitted only through blood-to-blood and sexual contact.
Hepatitis C
A viral infection (HCV) that is transmitted primarily by blood and blood products, as in blood transfusions or intravenous drug use, and sometimes through sexual contact.
HIV
Human Immunodeficiency Virus; the virus that causes the Acquired Immunodeficiency Syndrome (AIDS). HIV attacks and destroys the immune system by entering and destroying the cells that control and support the immune response system.
HIV Type 1 (HIV-1)
The HIV type responsible for the majority of HIV infections worldwide.
HIV Type 2 (HIV-2)
A virus very similar to HIV-1 that has been found to cause immune suppression. HIV-2 infections are found primarily in Africa.
IGZ
The Netherlands Health Care Inspectorate (www.igz.nl).
Immune system
The body’s defence system against invading antigens.
Leukocytes
White blood cells.
MSM
Men who have sex with men.
Person-year
A measure of time used in medical studies. A single person-year is 1 year lived by 1 person.
Retrovirus
A class of viruses which includes HIV. Retroviruses are so named because they carry their genetic information in RNA rather than DNA, and the RNA information must be translated "backwards" into DNA.
Reverse Transcriptase
After infecting a cell, HIV uses an enzyme called reverse transcriptase to convert its RNA into DNA and then replicates itself using the cell’s machinery.
RIVM
Dutch National Institute for Public Health and the Environment (www.rivm.nl).
Seroconversion
The change from an absence of HIV antibodies in the blood to the presence of those antibodies.
Seroprevalence
The incidence of disease in a given population.
SHM
Stichting HIV Monitoring (the Dutch HIV monitoring foundation, www.hiv-monitoring.nl).
T4 cell
See CD4 cell.
T4/T8 ratios
The existence and complicated action of two types of white blood cells, one which naturally suppresses the immune system and the other which naturally mediates immune action. Together these T-cells keep the immune system in balance.
UNAIDS
The Joint United Nations Programme on HIV/AIDS (www.unaids.org).
Vaccine
A substance that stimulates the body’s immune response in order to prevent or control an infection.
Viral load
The number of HIV particles in a millilitre of blood or another body fluid, such as semen or cerebrospinal fluid.
VWS
Dutch Ministry of Health, Welfare and Sport (www.rijksoverheid.nl).
WHO
World Health Organization (www.who.int).