Science and Development Network
News, views and information about science, technology and the developing world
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Definitions
- Antibiotic resistance
- Bird flu
- Climate change & insect-borne disease
- Genomics
- Malaria
- Nanotechnology for health
- Tuberculosis
List of terms for Tuberculosis
A
Active TB
Active tuberculosis disease, where the person has symptoms, which include weakness, weight loss, fever, appetite loss, chills and, in the case of pulmonary tuberculosis where the disease is in the lungs, a cough. Active TB is identified through a positive chest x-ray, and the person may or may not be infectious.
Adherence
Whether a patient sticks to their prescribed treatment programme.
B
BCG
Bacille Calmette Guérin; a vaccine aimed at preventing severe tuberculosis in children.
Bovine TB
Tuberculosis in cattle caused by Mycobacterium bovis; it can spread to humans, directly from cattle or by drinking milk from infected cows.
C
Case-finding
Identifying people infected with tuberculosis (TB) — usually by microscopic examination of sputum from people with suspected TB, who have had a cough for longer than 3 weeks.
Compliance
See Adherence.
Culture
Tuberculosis in phlegm or other body fluids that is grown and identified.
D
Disease ratio
The ratio of people infected with tuberculosis to those actually developing the disease.
DOTS
Directly-Observed Therapy, Short Course; the World Health Organization's strategy for tuberculosis treatment. It requires microscopy-based diagnosis, a free supply of good quality drugs, supervised treatment where healthcare workers observe patients as they take their medicine and an evaluation system to monitor and control activities. The strategy also calls for political commitment to controlling the disease.
DOTS-plus
DOTS adapted to tackle multidrug-resistant tuberculosis by adding reserve, or second-line, anti-tuberculosis drugs for patients who have undergone drug susceptibility testing or who have failed supervised re-treatment.
Drug susceptibility testing
A test done in a culture of Mycobacterium tuberculosis to determine which anti-tuberculosis drugs are effective against that particular sample.
F
Fluoroquinolones
A class of antibiotics used to treat drug-resistant tuberculosis; it includes ofloxacin, ciprofloxacin and moxifloxacin.
I
Isoniazid
The most commonly used first-line anti-tuberculosis drug.
L
Latent TB
The term applied to the status of people who are infected with tuberculosis but do not have active TB and remain healthy. The bacterium is assumed to be in a dormant state, although the exact nature of this state is under debate.
M
Macrolide
A class of antibiotics; some newer macrolides — for example, azithromycin and clarithromycin — are used to treat cases of multidrug-resistant tuberculosis.
Mantoux test
A test to determine past or present tuberculosis infections, carried out by injecting a set amount (usually 0.1 ml) of the antigen tuberculin into the skin with a hypodermic syringe.
MDR-TB
Multidrug-resistant tuberculosis; strains of tuberculosis resistant to at least the two main first-line tuberculosis drugs, rifampicin and isoniazid.
Mycobacterium
The bacteria genus that causes tuberculosis. The name means 'fungus bacteria', derived from the bacteria's mould-like forms in liquid-culture media.
N
Negative pressure room
An isolation room for infectious patients from which air is constantly extracted. The resulting slight negative pressure compared with the outside corridor allows any bacteria coughed up by patients inside the room to be extracted through a filter system rather than blowing into the corridor. These facilities are expensive and are rare in developing countries.
O
Open TB
Infectious tuberculosis in which mycobacteria are being discharged from the body — usually the result of cavities in the lung.
P
Para-amino salicylic acid (PAS)
One of the earliest anti-tuberculosis drugs, it is still occasionally used for treating multi-drug resistant strains of the disease.
Post-primary TB
Tuberculosis that only appears after a period of latency — usually 3 or more years after the initial infection.
Preventive therapy
Anti-tuberculosis drugs given to a person with latent tuberculosis, to prevent the development of the active disease.
Primary complex TB
The initial site of tuberculosis infection — usually in the lungs and adjacent lymph nodes.
Primary TB
Active tuberculosis following initial infection by mycobacteria.
Pyrazinamide
One of the first-line anti-tuberculosis drugs.
Pyridoxine
Vitamin B6; this is often prescribed with isoniazid to prevent certain side effects on the nervous system.
R
Rifampicin
One of the first-line anti-tuberculosis drugs.
S
Short-course chemotherapy (for tuberculosis)
So called to distinguish it from older anti-tuberculosis 18-month regimens, short-course therapy refers to the standard six–month course of drugs for the treatment of tuberculosis. Most short regimens are divided into an initial two–month intensive phase of four drugs (usually isoniazid, rifampicin, pyrazinamide and ethambutol), followed by a four–month continuation phase of isoniazid and rifampicin.
Sputum
Phlegm coughed up from inside the lungs.
Streptomycin
The first effective anti-tuberculosis drug, discovered by Albert Schatz and Selman Waksman in 1944. It is still used, especially in re-treatment regimens, but must be given by injection.
T
TB Meningitis
Tuberculosis of the membranes that surround the brain and spinal cord. TB meningitis is often fatal in children and often causes severe neurological damage in those who survive.
X
XDR-TB
Extensively drug-resistant tuberculosis; this is defined as MDR-TB with additional resistance to three or more of the six classes of second-line tuberculosis drugs.
