Anthelmintic resistance--looking to the future: a UK perspective

Area of Science:

• Veterinary Parasitology
• Animal Health
• Drug Resistance

Background:

• Anthelmintic resistance in farm animal nematodes is a growing concern with unknown full extent.
• Effective detection methods are vital for managing resistance and ensuring animal welfare.
• Current molecular detection methods are limited, primarily identifying benzimidazole resistance.

Purpose of the Study:

• To highlight the importance of detecting anthelmintic resistance in farm animals.
• To discuss current and potential methods for resistance detection.
• To emphasize the need for validated management strategies to delay resistance development.

Main Methods:

• Faecal egg count reduction test (FECRT).
• In vitro tests: egg hatch assay (EHA) and larval development assay (LDA).
• Polymerase chain reaction (PCR) based tests for specific resistance mechanisms.

Main Results:

• In vitro tests can be enhanced using discriminating doses for increased sensitivity.
• PCR-based tests are currently limited to detecting benzimidazole resistance.
• Molecular mechanisms for resistance to levamisole and macrocyclic lactones remain largely unknown.

Conclusions:

• Accurate detection of anthelmintic resistance is essential for implementing targeted control strategies.
• Maintaining parasite refugia and quarantining new animals are key management practices.
• Further research is urgently needed to develop new detection methods and control strategies, particularly for Fasciola hepatica.