Parascaris equorum in foals and in their environment on a Swedish stud farm, with notes on treatment failure of ivermectin.

The research article examines the presence of ascarid Parascaris equorum (Nematoda) in foals and their environment on a Swedish stud farm, particularly considering the ascarid’s egg excretion pattern and the effectiveness of the common anthelmintic treatment, ivermectin.

Research Objectives and Methodology

• This study intended to determine the level of environmental contamination caused by the ascarid Parascaris equorum and its egg excretion pattern relative to anthelmintic treatment in a Swedish stud farm. Heavy infestations of ascarids can be a significant health risk to foals.
• Over the course of several months, researchers collected faecal samples from 15 foals. These foals were routinely dewormed every eight weeks with an ivermectin-based paste at a standard dose rate of 0.2 mg/kg bodyweight.
• Soil samples were also collected from four paddocks frequented by the foals. The research team then counted the number of Parascaris equorum eggs per gram in both the faecal and soil samples.

Research Findings

• The researchers found that Parascaris equorum egg excretion in foals began when they were between 3 and 4 months old. The highest egg excretion levels occurred when the foals were around 5 months old, after which there was a marked decline.
• Interestingly, regular deworming with ivermectin seemed to have no significant effect on egg excretion rates. Examples included four out of five foals examined 10 days after treatment, where the egg excretion rate actually increased.
• When either fenbendazole or pyrantel embonate were used instead of ivermectin, the treatments were found to be more effective, highlighting the potential treatment failure of ivermectin.
• Lastly, environmental contamination analysis showed a significantly higher number of eggs in the soil from the permanent paddock when compared to temporary and summer paddocks, indicating a potential risk of infection from environment

Implications of Research

• The findings suggest the possible ineffectiveness of ivermectin as a treatment for Parascaris equorum in foals, indicating the need for further research or considering alternative treatments such as fenbendazole or pyrantel embonate.
• This study highlights the importance of monitoring and managing the environment in equine farms to prevent high levels of ascarid infection, particularly in areas where foals are kept.
• The research results provide useful insights for veterinarians, equine farm managers, and animal health researchers regarding parasitic control strategies.