Bovine TB: APPENDIX G - Glossary of Key Terms
- BCG
- "Bacille Calmette Guerin" - a changed strain of M. bovis developed by the Drs Calmette and Guerin in the early part of this century, repeatedly sub-cultured until it became non-virulent. Used since the 1920s as a vaccine to protect against human tuberculosis.
- Breakdown
- MAFF define a breakdown (or a TB incident) 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.
- Buffer zone
- an area separating different trial areas and different triplets. There are inner and outer buffer zones; these are explained in Section 4.5. Data on the incidence of TB in cattle in the buffer zones will not be included in the main analysis of the trial.
- 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.
- Dirichlet tesselations
- technique used in the delineation of likely badger territories, based on the location of main setts. Dirichlet tessellations are polygons, each centred on a main sett; every point within the polygon is closer to its own main sett than to neighbouring setts.
- Epidemiology
- the study of the distribution and dynamics of disease in a population. 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.
- Gamma interferon
- a product of white blood cells generated during an immune response.
- Genome
- the genetic composition of a cell or individual.
- Genotype
- the distinctive DNA fingerprint distinguishing one individual from another.
- Incidence
- the rate at which new cases of infection arise in a population.
- Incident
- (see breakdown)
- Multivariate (or multifactorial)
- a general term for the many methods of analysis important in investigating multiple variables.
- 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.
- Pathogenesis
- the processes within an individual involved in the development of disease.
- Perturbation
- disruption of the social organisation or spatial structure of badger populations, such as that caused by culling.
- Power (statistical)
- the probability that a difference between treatments will be detected given a particular magnitude of underlying difference between them.
- Prevalence
- the proportion of a population infected at a particular time.
- Randomised field 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 (i.e. 'reacts') to the tuberculin skin test.
- Sensitivity
- the proportion of true positives detected by a diagnostic method.
- 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.
- Specificity
- the proportion of true negatives detected by a diagnostic method.
- Spoligotyping
- spacer~oligonucleotide typing (a molecular typing technique), used to distinguish different strains of the TB organism.
- Strain
- isolate of a bacterial species which is differentiated from other isolates of the same species by particular characteristics.
- Treatment
- term used to refer to the relevant action, i.e. proactive culling, reactive culling or survey only, which will be applied in the trial areas. Each triplet has three trial areas and each trial area will be subject to one of the three different treatments
- 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.
- Tuberculin
- a sterile protein extract derived from the tubercle bacterium and used to diagnose TB in cattle by skin testing (also known as Purified Protein Derivative or PPD).
On to Appendix
H 
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Page last modified:
12 August 2003
Page published: 5 February 2003