EPM Explained: Causes, Symptoms, Treatment, and Prevention

EPM is one of the most common and complex neurological diseases facing horses in North America, but what really causes it, and are there ways to protect your horse? In this episode of Ask an Expert, equine veterinarian Dr. Phil van Harreveld breaks down the real risks of EPM, explains early warning signs, debunks common myths, and gives actionable advice on prevention, diagnosis, and treatment for every horse owner.

Episode Highlights: 

4:00: What causes EPM, where the parasite is found, and whether some horses are more susceptible than others 

12:00: What owners can do to help reduce the risk of EPM in horses that have been exposed to the parasite 

22:00: Common myths and misconceptions about EPM symptoms and diagnosis 

31:20: Treatment options for EPM and how effective they are 

34:20: How often EPM leads to neurological symptoms, how severe those symptoms can be, and the likelihood of recurrence after treatment

Meet the Expert, Dr. Phil van Harreveld

Dr. van Harreveld received his Doctor of Veterinary Medicine from North Carolina State University, and his master’s degree and surgical board certification from Kansas State University. He practiced as an equine veterinary surgeon for more than 22 years, founding the first equine referral hospital in Vermont, which he operated for over two decades. In addition to handling the hospital’s field cases, he managed the in-house medical and surgical case load. He joined the Merck Animal Health equine veterinary professional services team in 2022.

Episode Sponsor

Connaway & Associates 

The friendly and knowledgeable team at Connaway & Associates brings together more than 30 years of experience to offer a wide range of insurance services, including horse insurance, farm insurance, and liability insurance.

Visit www.connaway.net or call 501-868-8084 to explore your options.

Brought to you by Ride iQ

This episode is part of the Ask An Expert podcast series, usually available exclusively in the Ride iQ app, where members have access to more than 200 expert interviews covering training, horse care, sports psychology, and more.

Ride iQ helps everyday riders ride with more clarity, confidence, and purpose through on-demand audio lessons from world-class coaches. Members also get weekly live Q&As with equestrian experts, exclusive podcast episodes, dressage test playbooks, and supportive community conversations that make learning feel fun and doable.

If you’d like to explore what Ride iQ offers, you can learn more and start your free 14-day trial at Ride-iQ.com.

Want straightforward, expert advice on keeping your horse sound and thriving? Dr. Erica Lacher’s eight-part program, Horse Health Essentials, is now available, and you can use code POD35 for 35% off. Learn more at RideIQElevate.com/horse-health.