Bovine TB: Research project summary
Project SE3017: Development and evaluation of strain typing methods for Mycobacterium bovis.
Project duration: 5 years 7 months
This project aimed to evaluate the suitability of all current molecular typing techniques, and to develop more sensitive methods that allow high-throughput typing. Spoligotyping combined with VNTR analysis was found to maximise surveillance of M. bovis genotypes circulating in GB. These PCR based techniques were found to be superior to REA and RFLP in ease of use, high-throughput, ease of recording results, portability of results between laboratories, and identification of genotypic variation. AFLP was also tested but did not provide useful or reliable information.
While the current loci analysed by spoligotyping and VNTR analysis appear to have identified all major genotypes within the M. bovis GB population, results suggest that there may be more informative loci that could be used, however, a population survey of strains isolated in GB would be necessary to determine which are best.
Molecular typing techniques for M. bovis were also standardised between the PHLS and the VLA to improve monitoring of human M. bovis infection. Analysis of 50 recent cases of human M. bovis suggest that most result from either reactivation of an infection acquired prior to pasteurisation of milk or from people new to GB.
An epidemiological and immunological survey was carried out on 387 farmers. Risk factors for exposure to M. bovis in farmers were found to be greater for diary than beef farmers, and risk increased with the size of the diary herd and by drinking unpasteurised milk. An association was also observed for various types of poultry farming.
Glossary
Spoligotyping - Spacer oligonucleotide typing
VNTR - Variable Number Tandem Repeats
PCR - Polymerase Chain Reaction
REA - Restriction Endonuclease Analysis
RFLP - Restriction Fragment Length Polymorphism
AFLP - Amplified Fragment Length Polymorphism
PHLS - Public Health Laboratory Service
VLA - Veterinary Laboratories Agency
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Page last modified:
July 7, 2008