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Can detection and typing of brucellosis in animals be further improved? - SE0309

The rapid and specific diagnosis of Brucella in clinical samples from livestock is essential for brucellosis surveillance and too fulfil our statory obligations to control and maintain our Brucela-free status in the UK. The risk of re-introduction of brucellosis throuigh either importation or following deliberate release remains a realistic threat. To increase the likelihood of the detection of these organisms the aim is to develop rapid, sensitive and specific tests that can be applied to samples from a variety of sources. To this end, we will develop molecular based diagnostic tests and typing techniques to support the rapid diagnosis and typing of Brucella.
01: To evaluate the cloned open reading frames of B melitensis 16M (ORFeome) for their efficacy as potential diagnostic antigens. Screening of antigens should be complete by the end of the second year(31.3.05) to allow for parallel testing of the new candidate antigens alongside the tests we currently offer.

02:To further reduce detection times for brucellosis by development of a real-time light cycler method for detection. Optimisation of this assay for detection of Brucella spp. should be complete by the second year of the study. We aim to further develop this test by modifying amplication targets and undertaing simultaneous identification during the final year of the study. This will utilise unique targets determined by comparative analysis of brucellae (see sepatate application).

03: To further investigate typing of brucellae, we will identify tandem repeat sequences present in sequenced genomes and utilise this to create signature profiles for representative species and biotypes of Brucella. This could form the foundations for a PCR-based detection and typing approach with the potential power of resolution to differentitate at a clonal level. Full evaluation of this approach will require the duration of the funding period.

04: We will design a multiplex abortion screen to cover a range of bacterial causes of abortion. This should facilitate rapid diagnosis at the regional laboratory level. Such a test will simultaneously detect a range of pathogens and could in consequence provide enhanced reactive data in response to abortion problems. Furthermore, use of universal 16S rDNA-targeting primers will be used to screen for unidentified or non-cultivable bacteria present in aborted material. This test will be developed during the first year of the project to allow time for technology transfer to Regional laboratories and assessment of its efficacy with clinical material.

05: To evaluate our current serological tests for the detection of rough strains. This will be done using serum collected from animals where known problems exist with rough strains of Brucella, for example, B. ovis. In addition, we will evaluate our tests with serum collected from animals vaccinated with RB51, a rough vaccine strain of B. abortus, now routinely used in the USA. Evaluation of our current serological tests for the detection of Brucella antibodies in response to infection with rough strains will be undertaken in the first year of the study. Assessment of novel new diagnostic antigens for the detection of rough strains will be done in combination with objective 1 during the second study year.

06: To evaluate the efficacy of molecular tests developed in previously DEFRA-funded work (SE0303 & SE0304). During these studies we have developed molecular tools to assist the diagnosis of brucellosis. These howver, have not yet been fully evaluated using fresh clinical material. We propose to parallel test these new techniques with our current serology based approaches on `high risk` import screening samples. We will also endeavour to further evaluate these tests using field-collected samples from Northern Ireland and Eire. This parallel testing would be undertaken during the first year of the study.
Project Documents
• Final Report : Can detection and typing of brucellosis in animals be further improved?   (241k)
Time-Scale and Cost
From: 2003

To: 2006

Cost: £270,831
Contractor / Funded Organisations
Veterinary Laboratories Agency
Animal Diseases              
Animal Health              
Plants and Animals              
Fields of Study
Animal Health