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Validation and epidemiological application of molecular methods for monitoring M. bovis in the environment - SE3231

Bovine tuberculosis (bTB) is a serious and growing disease of cattle in Britain. The study of Mycobacterium bovis, the bacteria that causes bTB, poses particular challenges with regard to its specific detection once deposited in soil due to its similarity to closely related species that are also found in the environment, and due to the intrinsic nature of the environmental bacillus once deposited via contaminated animal excreta. Information gained from sequencing the complete genome of M. bovis has revealed a number of unique DNA sequences (or regions of difference (RD)) compared to other closely related species, and these differences provide a basis for the development of highly specific DNA probes that detect and amplify only M. bovis DNA. A region of difference known as RD4 is deleted in M. bovis but not in other closely related species, and this fact was exploited to develop a DNA detection and enumeration technique (real time PCR) specifically for M. bovis.

This proposal will extend past research to optimise PCR assays that will allow discrimination between M. bovis and closely related species from environmental samples. A ring trial will be performed by participating research institutes (VLA and Warwick University) to test the sensitvity, specificity, reliability and reproducibility of the PCR on a range of positive and negative laboratory and field samples. Complimentary studies will address questions about the viability, abundance and metabolic activity of M. bovis cells in different environmental substrates. Growth of the cells isolated from PCR positive environmental samples on culture media will be performed in an attempt to identify the strains found in the environment and compare these to strains found in the tissues of infected cattle and badgers. Towards field application of the PCR, environmental sampling protocols will be developed in the context of improving farm biosecurity, and as a non-invasive marker of badger infection.
Project Documents
• EVID4 - Final project report : SE3231 final report SID5   (870k)
Time-Scale and Cost
From: 2007

To: 2010

Cost: £1,309,583
Contractor / Funded Organisations
Veterinary Laboratories Agency, University - Warwick
Animal Diseases              
Animal Health              
Bovine Tuberculosis              
Disease Control              
Method Development              
Plants and Animals              
Fields of Study
Animal Health