Survey of anthelmintic resistance in a Romanian horse stud using three different methods.

This research study investigates the problem of parasite resistance to a prevalent de-worming drug in horses on a farm in Romania. A variety of testing methods were used to evaluate the extent and nature of this resistance, revealing that a mix of methods may be necessary for accurate assessments.

Study Overview and Objectives

• The research was geared towards assessing the resistance of a certain type of horse parasites called cyathostomins to a drug class known as benzimidazole (BZ) anthelmintics, which are commonly used to de-worm horses.
• This study was conducted on a stud farm in Romania, and the resistance issues were investigated using three different methods – Fecal Egg Count Reduction Test (FECRT), Egg Reappearance Period (ERP), and Polymerase Chain Reaction (PCR).

Methodology and Findings

• Prior to treatment, a variety of parasites were identified in 18 horses on the studied farm.
• After treatment with the BZ anthelmintic drug, Fenbendazole, only certain types of parasites were found, suggesting a degree of treatment success.
• However, testing also revealed that one horse continued to show resistance to Fenbendazole, as demonstrated through the FECRT and ERP tests.
• More extensive analysis using PCR revealed that genetic resistance and susceptibility to the anthelmintic drug was observed in most samples. In some horses, only susceptibility or resistance was observed.

Conclusion and Implications

• There were inconsistencies between the results from the PCR test compared to the FECRT and ERP tests. This suggests that employing a combination of various methods can provide a more comprehensive understanding of anthelmintic resistance in horses.
• The existence of genetic resistance and susceptibility to BZ drugs indicates that these parasites’ capacity to survive such treatment may be partly genetically determined.
• Recognition of such resistance is crucial for the effective management of parasites in horse populations, potentially necessitating diversification in de-worming methods and drugs used in practice.