Standardization of the egg hatch test for the detection of benzimidazole resistance in parasitic nematodes
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The ability to reliably detect anthelmintic resistance is a crucial part of resistance management. If data between countries are to be compared, the same test should give the same results in each laboratory. As the egg hatch test for benzimidazole resistance is used for both research and surveys, the ability of different laboratories to obtain similar results was studied through testing of known isolates of cyathostomins, Haemonchus contortus, Ostertagia ostertagi, and Cooperia oncophora in programs supported by the EU (Cost B16 and FP6-PARASOL). Initial results showed difficulties in obtaining reproducible and similar data within and between laboratories. A series of ring tests, i.e., simultaneous and coordinated rounds of testing of nematode isolates in different laboratories was subsequently performed. By adopting identical protocols, especially the use of deionized water and making dilutions of thiabendazole in dimethyl sulfoxide in the final ring test, laboratories correctly identified both susceptible and resistant isolates. The protocols for the test and preparation of solutions of thiabendazole are described.
KeywordsResistant Isolate Thiabendazole Hatch Rate Ring Test Anthelmintic Resistance
The financial support through the EU-Cost action B16 and the FP6 PARASOL (FOOD-CT-2005-022851) project is thankfully acknowledged. We are most thankful to all colleagues from the laboratories listed in Table 1 involved in performing the ring tests.
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