Can Bulk Milk Revolutionise TB Testing?

A Defra review of UK bovine tuberculosis (bTB) strategy acknowledged bTB as the most pressing animal health problem in the UK.

The Enferplex Bovine TB Antibody Test is a multiplex ELISA test for the detection of bTB in serum and milk, developed as a collaboration between three companies: SureFarm Ltd, a subsidiary of Synergy Farm Health Ltd (England), MV Diagnostics Ltd (Scotland) and Enfer Scientific ULC, part of Enfer Group (Eire).

The test shows high sensitivity and specificity for the detection of bTB in bulk milk. The use of bulk milk as a surveillance tool offers significant opportunities in the control of TB, reducing costs to both farm and taxpayer through easier surveillance and improved control.

The test is in the process of evaluation for approval by the World Office of Animal Health, which if accepted would require the UK Government to place mandatory restrictions on any herd testing positive. Therefore, there is a window of opportunity to develop understanding of the value that the test would bring to bTB control in the UK, without risk to the dairy industry and individual farms.

We plan a GB wide, longitudinal study on the outcomes of testing bulk milk with the Enferplex bTB Antibody Test. Specifically, the study will focus on:

1. Test results obtained from herds currently under restriction. While the sensitivity of the test has already been elucidated for the OIE submission, this was based on a single time point and repeating the test may enhance sensitivity.

2. How many herds currently designated Officially Tuberculosis Free (OTF) would be determined positive by the test.

3. Understanding the relationship between seropositivity and/or the number of positive antigens and herd bTB status.

4. Understanding the predictive value of changes in seropositivity and/or the number of positive antigen reactions for tracking progress, or otherwise, of herd bTB control measures. Falling levels of either parameter may suggest a herd moving towards disease freedom; vice versa, rising levels may indicate that current actions are failing to control disease where the herd is already under restriction.

5. Understanding whether the test could be used as a monitoring tool for low risk OTF herds.

The project has the full support of the National Farmers Union (NFU) and the British Cattle Veterinary Association (BCVA).