World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guideline for diagnosing anthelmintic resistance using the faecal egg count reduction test in ruminants, horses and swine.

The research article provides a guideline for diagnosing anthelmintic resistance in ruminants, horses, and swine using the faecal egg count reduction test (FECRT). It includes recommendations for experimental design, fecal egg count method, statistical analysis, interpretation of results, and more.

Understanding the Faecal Egg Count Reduction Test (FECRT)

• The FECRT is used to determine the effectiveness of anthelmintic drugs (medications that expel parasitic worms from the body) in various livestock species in the field.
• The test involves counting the number of parasite eggs in an animal’s feces before and after treatment with an anthelmintic compound.
• If the count of eggs is significantly reduced post-treatment, the drug is considered effective. However, if the egg count does not decrease significantly, this may indicate anthelmintic resistance.

Updating the Guidelines for FECRT

• This study establishes new guidelines for FECRT, aiming to improve its standardisation and performance.
• The new guidelines highlight four distinct sections: major issues relevant to the FECRT execution, general recommendations applicable across all animal types, specific guidance for different livestock varieties, and detailed descriptions for conducting the FECRT for each animal species.

Key Changes in the New Guidelines

• Firstly, the study recommends using a paired study design – assessing FEC of the same animals pre- and post-treatment. This eliminates the need for untreated control animals as proposed in the older guidelines (unpaired design).
• Secondly, instead of needing a minimum mean FEC for the group, the new guidelines require a minimum total count of eggs under the microscope before applying any conversion factors.
• Thirdly, the new recommendation provides more flexibility in terms of the size of the treatment group, using three separate options based on the expected number of eggs counted.
• Lastly, the newest guidelines cater to all significant livestock species. The benchmarks for defining reduced efficacy now adapt to different host species, anthelmintic drugs, and parasite species.

Significance of the New Guidelines

• These new guidelines provide a more refined methodology and improved standardization of FECRT procedure.
• They are intended to increase the accuracy and reliability of anthelmintic resistance diagnosis, serving both scientific studies that require detection of small changes in efficacy and routine veterinary use to spot larger changes in efficacy.
• The changes could support more effective parasite management strategies and, by extension, improve livestock health and productivity.