Home > About > Glossary

Glossary: A

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

ABSL

Animal biosafety laboratory (see BSL).

Acid-fast bacilli

Difficult-to-stain bacteria that, once stained, resist decolorizing with acid washings; used in microbiology labs to identify mycobacteria such as M.tb.

Active case detection

Encouraging potential TB cases to submit sputum samples for smear or culture testing; as opposed to standard DOTS strategy of relying on sick patients to present themselves at clinics for diagnosis and treatment.

Active Disease

Active TB disease can be pulmonary or extrapulmonary; a term used to distinguish TB disease from latent TB infection (LTBI).

Acute

Rapid in onset or short in course; as opposed to chronic.

Ad35

Adenovirus-35, a double-stranded DNA virus used as a vector in vaccine research; there is less pre-existing immunity to Ad35 than to Ad5, hence lower doses can be used.

Ad5

Adenovirus-5, a double-stranded DNA virus used as a vector in vaccine research.

Adherence

The process of regularly and accurately following a treatment protocol, exercise regimen, or religious practice.

Adjuvant

A substance given along with a vaccine to enhance its immune effects.

Aeras

Aeras Global TB Vaccine Foundation, a US-based product-development partnership (PDP) which is seeking to develop more effective TB vaccines by strengthening BCG or by adding various booster immunization approaches.

Aerosol

Liquid droplets suspended in the air; M. tb. is transmitted in aerosol form by an infected person coughing.

AFB

Acid-fast bacilli, group of bacteria, including M. tb. Sputum samples are smeared on a slide, dyed with Ziehl-Neelson stain, and examined by microscopy, which can identify a smear-positive case of TB disease. AFB also detects non-viable (dead) bacteria, however.

Agar

Jelly-like substance made from galactose sugar obtained from cell walls of red algae or seaweed and used as a culture medium in microbiology laboratories.

AIDS

Acquired immunodeficiency syndrome, a number of serious and life-threatening diseases and conditions caused by progressive immune deficiency triggered by HIV infection.

Airborne

An infectious organism which can be transmitted from an infected host to a susceptible one through the air; influenza, SARS, and TB are airborne diseases.

Algorithm

A decision tree used to determine the pathway a person takes to obtain diagnosis and treatment.

Aliquot

An amount that is an exact fraction of a larger amount; used in laboratory work.

Ambulatory

Able to walk.

Amikacin

An injectable aminglycoside antibiotic used in treatment of MDR-TB.

Aminoglycoside

A toxic, potent class of injectable antibiotic drugs including amikacin, kanamycin, and streptomycin, which block bacterial protein synthesis.

Anergy

Non-reactivity to immune stimuli defined by the lack of delayed type hypersensitivity (DTH) to antigen exposure; some people with HIV, particularly with low CD4 counts, are anergic and non-responsive to tuberculin skin testing (TST). Anergy disappears after ART induced immune reconstitution.

Anoxia

Being without oxygen.

Antibiotic

Any drug with anti-bacterial activity.

Antibody

Immune system proteins produced and secreted by B cells in response to an infection or autoimmune inflammation.

Antigen

Processed proteins from an invading pathogen (virus or bacterium) which are chopped up by antigen-presenting cells (APC) such as dendritic cells and macrophages and presented to T cells to elicit an immune response; sometimes antigens are used for diagnosis (TST, IGRA) or as putative vaccines (Ag85A-ESAT-6).

APC

Antigen presenting cells of the immune system, which process invading pathogens by phagocytosis and break them down into protein subunits for presentation to T and B cells. Macrophages and dendritic cells are APC.

ART

Antiretroviral therapy: anti-HIV treatment, usually refers to combinations of ARVs given together to maximally and durably suppress HIV RNA, preserving or restoring CD4 count and immune function.

ARV

Antiretroviral: a drug with anti-HIV activity.

ATS

American Thoracic Society, a US-based professional society.

Attenuated

Weakened; through progressive breeding or artificial selection; e.g., BCG is an attenuated form of M. bovis.

AUC

Area under the curve, a pharmacokinetic measure of drug exposure.