Bacille Calmette Guerin (BCG)
an attenuated strain of M. bovis used for human vaccination: the only vaccine that has produced a significant immunity against M. tuberculosis and at the same time has proved safe enough for human subjects.

Breakdown
MAFF define a breakdown as occurring when one or more reactors are revealed by the tuberculin skin test or when disease is suspected in either live cattle showing clinical disease or in carcases with lesions at post-mortem examination.

Confirmed breakdown
a herd breakdown where the disease has been confirmed in one or more animals, usually reactors, by detection of lesions at post-mortem and/or through culture of M. bovis.

Epidemiology
the study of the distribution and dynamics of disease in populations. Its purpose is to identify factors which determine the occurrence of disease, and to provide a basis for intervention programmes. Epidemiological methods are also used to assess the variance, severity and magnitude of disease and related risks.

Genome
the sum total of genes in the chromosome(s) of an organism.

Incidence
the rate at which new cases of infection arise in a population.

Lesion
a pathological change in organs or tissues produced by TB or other causes of disease.

Mycobacterium
a family of related bacteria characterised by a lipid-rich waxy coat that results in acid fast staining, which include species that cause TB. The mycobacterium responsible for bovine tuberculosis is mycobacterium bovis.

Power (statistical)
the probability of detecting an effect of a given size with a stated level of significance.

Prevalence
the proportion of the population infected at a particular time.

Randomised trial
technique for comparing treatments in which specific treatments are allocated to trial areas by physical randomising device in order to avoid allocation biases and to ensure comparability.

Reactor
animal which gives a positive result (ie "reacts") to the tuberculin skin test.

Sensitivity (of diagnostic test)
proportion of infected animals tested correctly identified.

Sett
burrow system which badgers use for shelter and breeding.

Social group
group of badgers (averaging six to eight in a group, although a maximum of 25 has been recorded) occupying one or more setts within a well-defined territory from which badgers of other social groups would be excluded.

Spoligotype
a particular strain identified through a molecular typing technique called spoligotyping.

Spoligotyping
spacer-oligonucleotide typing (a molecular typing technique).

Strain
isolate of a bacterial species which is differentiated from other isolates of the same species by particular characteristics.

Triplet
group of three trial areas, each subject to a different treatment. Within each triplet, one area will be allocated to proactive culling, one to reactive culling and one to survey only.

Unconfirmed breakdown
a herd breakdown which occurs when all reactors have no visible lesions and are culture negative for M. bovis.

Zoonosis
disease communicable between animals and man.