WP 3 – Standardisation of tests for resistance

Introduction

The ability to detect resistant worms in both sheep and cattle is crucial to the whole concept of delaying and managing anthelmintic resistance. Therefore, it is important to have standardised testing methods that are interpreted correctly and ensure that results are comparable in different countries.

Objectives

• Ring test existing laboratory tests for uniformity of results in order for the SOPs to be published.
• Produce standard operating procedures (SOP) for running and interpreting tests for anthelmintic resistance.
• Write guidelines on the conducting of surveys for anthelmintic resistance.

Justification

It is now recognised that the methods used in veterinary medicine for the detection of anthelmintic resistance need to be standardised in order that result from different countries can be compared and the extent of anthelmintic resistance can be reliably established. The most commonly used test for the detection of resistance is the faecal egg count reduction test (FECRT) since it can be run with any anthelmintic as part of the on farm worming strategy. It has not yet been standardised for use with cattle nematodes and interpretation of the results also requires agreement, especially when loss of activity appears to be low.
Laboratory based in vitro tests for the detection of resistance have been described. However, recent results from an European ring test of the egg hatch test (EHT) for benzimidazole resistance obtained variable results from different institutes. This stresses the importance of standardising the tests and their interpretation and producing SOPs that give similar results in every laboratory. How the different types of tests are best used in surveys for anthelmintic resistance in sheep and goat flocks and cattle herds also requires agreement.

Expected results.

1. Publication of SOPs for the detection of anthelmintic resistance, based on the evaluation of tests from several laboratories for both in vivo and in vitro tests.
2. Production of recommendations for undertaking surveys for the extent of anthelmintic resistant nematodes in sheep and cattle.

Organization

This work package involves scientists at the Universities of Bristol (WP3 leader), Ghent, Uppsala and Hannover as well as the INRA, the Moredun Research Institute and the Slovak Academy of Sciences.