Test Development and Proof of Concept

The Test Development Programme underpins and enhances our testing portfolio by developing and validating new routine tests.

The Test Development Programme supported projects across a range of diseases and VLA science programmes in 2007/8 with the aim of strengthening VLA’s testing portfolio. Additionally, we have developed ‘proof of concept’ funding, which has allowed VLA scientists to undertake further work on tests with commercial potential.

Avian Influenza Diagnostic Tests

AI has been high profile recently and VLA is the Community Reference Laboratory. Routine screening is now based on PCR detection. Various sampling protocols for the detection of AI were assessed and an optimal strategy has been defined and put into use. An internal control PCR has been validated to show whether avian material has been successfully transferred from a swab to the PCR reaction. If avian material is not detected in the internal control PCR reaction, the AI PCR cannot be interpreted as it is likely that the test sample was not appropriate. Projects have also been conducted to develop and validate immuno-histochemical (IHC) and lateral flow device (LFD) based methods for AI.

New Technology

Luminex technology allows the detection of multiple analytes at the same time in the same tube. Targets can be antigens, antibodies or nucleic acids. We have assessed this approach to simplify the typing of Mycobacterium bovis (‘spoligotyping’) by using luminex as the detection method to replace the traditional reverse line blotting. Preliminary results are promising and the approach will be validated and transferred into routine use during the coming year. Applications for multiplex detection of serological targets for bovine respiratory diseases have also been assessed.

Further Validation Studies

Immuno-blotting methods for the confirmation of two avian mycoplasma infections have been developed and validated. These will be introduced into routine testing and provide enhanced specificity compared to the rapid slide agglutination test (RSAT) which is the current screening test. Real time PCR diagnostics for Johne’s disease (Mycobacterium paratuberculosis) have been strengthened. Validation for the porcine reproductive and respiratory syndrome virus (PRRSV) PCR has been completed and the test introduced into routine use.

A micro-array based system has been validated for the detection of anti-microbial resistance genes in E.coli and Salmonella. This will be used as a routine testing method at VLA and is available to other laboratories via Identibac® (click here for further details).