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Validation of diagnostic tests to support plant health

Periodic Reporting for period 1 - VALITEST (Validation of diagnostic tests to support plant health)

Reporting period: 2018-05-01 to 2019-10-31

Plant pests (bacteria, virus, fungi, nematodes, arthropods or weeds) are responsible for major crop losses. Accurate and reliable detection and identification of these pests are essential to avoid or reduce economical costs and trade disruptions and to support surveillance activities and crop monitoring. Validation is essential to provide information on the performance of the tests. However, since most detection and identification tests are only validated on an intra-laboratory basis or through limited Test Performance Studies (TPS), there is a need to further harmonise practices. The VALITEST project aims to improve diagnostic by producing validation data, harmonising processes and enlarging/triggering enlargement of the commercial offer for reliable detection and identification tests.

The project includes two rounds of TPS for twelve specific pests for which interest was identified among the different stakeholders. The tests to be evaluated could be performed either in a laboratory or on-site. The VALITEST project is also working on the improvement and harmonisation of the test validation processes, of the production of reference materials and on the uptake of the tests by end users. The outcomes of the project will stimulate, optimise and strengthen the interactions between stakeholders in Plant Health for better diagnostics and lay the foundations for structuring the quality and the commercial offers for plant health diagnostic tools thanks to a dedicated association and a quality charter.
VALITEST has prepared and organised a first round of test performance studies covering the following pests: Erwinia amylovora, Pantoea stewartii subsp. stewartii, Citrus tristeza virus, Plum pox virus, Fusarium circinatum and Bursaphelenchus xylophilus. A second round is currently under preparation on the following pests: Tomato brown rugose fruit virus, Tomato spotted wilt virus, Plum pox virus (on-site testing), Xanthomonas citri pv. Citri, Xylophilus ampelinus, Cryphonectria parasitica. This TPS activity is the core of the technical work of the project, in terms of workload.

The project has started improving validation approaches for diagnostic technologies to maximise their usefulness for users (diagnosticians) and decision-makers (at National, European or Regional levels) and their use in routine diagnostics. In this context, the description of the use of statistical tools has been developed.
VALITEST has established guidelines for quality assurance and Standard Operating Procedures (SOPs) for the production of the different types of reference materials used in validation studies for phytosanitary tests including possible quantification of targets in reference material.

A survey has been sent to the different stakeholders to identify the demand for current and future testing needs.
Through a workshop and a survey, VALITEST has evaluated the needs of laboratories in terms of proficiency testing and estimated the feasibility of a horizontal approach to evaluate the proficiency of laboratories.
In the framework of the project, the database on diagnostic expertise (Validation data) maintained by EPPO is being updated. Validation data generated during the project will be stored in this public database.

Dissemination of the results of the project to a wide public including researchers, policy-makers and other stakeholders is carried out notably through a project website and social media.
All the work has been performed in strong collaboration with SMEs and discussions on the establishment of an EU Association of the Plant Health Diagnostic Industry have been initiated.
The two rounds of test performance studies will produce validation data i) for prioritised pests ii) in a range of matrices iii) for the identified tests where no or limited validation data is currently available and iv) for a range of diagnostic platforms (both laboratory and on-site based). These data will be made publicly available on a database dedicated to validation of plant health tests (the EPPO diagnostics database), and depending of the data obtained, diagnostic protocols will be updated (e.g. update planned for the EPPO protocol on Bursaphelenchus xylophilus with the inclusion of a LAMP test validated within the project).
In the long term, the project improves the current EPPO Standards for validation of tests for plant pest diagnostics (PM 7/098) and for the performance of interlaboratory comparisons (PM 7/122) by incorporating new statistical tools and predictive models. VALITEST is preparing the future of diagnostics and is developing best practice guidelines for the validation and application of non-targeted (generic) diagnostic procedures, using next generation sequencing procedures (NGS) for the detection of viruses in plant pest diagnostics as a model. The project provides guidelines for quality assurance and Standard Operating Procedures (SOPs) for the production of the different types of reference materials used in validation studies for phytosanitary tests including possible quantification of targets in reference material. During the course of the project, these guidelines and SOPs are not only drafted but also tested to match with the needs of the users.
VALITEST will develop guidelines on a horizontal approach allowing proficiency testing to be undertaken without the laboratories having to participate in proficiency tests for all the tests used. The outcome of this activity will help the laboratories manage and better show the extent of their competence and their proficiency in testing. This horizontal approach may also stimulate the offer of new services by SMEs (such as appropriate proficiency tests).

The project supports plant health policies by engaging with stakeholders to ascertain views on and demand for existing tests and operating procédures, as well as the attributes that lead to adoption for future tools. The project also assesses the end markets for tests including their potential market (e.g. reduction in yield losses) and non-market (e.g. reductions in woodland losses) impacts.
This engagement with stakeholders incorporates elements of the multi-actor approach in considering the demand for, and benefits from, the validation of existing tests but also with the examination of their requirements for future tests. In addition to the validation of the tests, this approach introduces an element of co-design with end-users influencing the products brought to the market.

Results of the project will be disseminated to a wide public including researchers, policy-makers and other stakeholders, through different meetings, webinars and targeted training organised at EPPO and EU levels. 2020, as the international year for plant health, will be an excellent opportunity for this dissemination.

Among the objectives of the project, the establishment of an EU Association of the Plant Health Diagnostic Industry will ensure the market sustainability of the SMEs by facilitating dialogue with decision makers and end users. The development of an EU Plant Health Diagnostics Charter will contribute to increasing the competitiveness of SMEs and enhance the quality and reliability of their products worldwide. In the context of the establishment of EU reference laboratories in plant health, this initiative is very appropriate.
Preparation of samples for a Test Performance Study