08/27/2025
School has started in the Midwest which can only mean one thing – its football season.🏈 Everyone understands how touchdowns work in football, but few people know how to score points in the battle against EPM.🐛 Lets break it down with a football analogy.
🌟Dr. Gran’s disclaimer: I try really hard to live in a “football free” bubble, but am making a single exception in an effort to discuss this very important topic. Please do not try to initiate football conversation with me though, because I don’t really care who wins the World Series of American Football🌟
Here we go. Stick with me for a minute. 👩🏫
Columbia City’s🦅 first home game is this Friday against Plymouth. There are some players on the team that are called “defenders” (how am I doing so far?). Their job is to prevent the offenders on the other team from getting to the end zone. If the offenders get to the end zone, magically points will show up on the score board.6️⃣ If the defenders do their job, there will be no points.0️⃣ Plymouth points will make CC work harder. You with me?
The nervous system of the horse works the exact same way. 😆 Every time the body “sees” EPM organisms, it makes antibodies in the blood to protect itself. Sometimes, the organisms get past the antibodies into the nervous system (end zone). When this happens, the nervous system makes its own antibodies.
• Offenders = EPM organisms🐛
• Defenders on the field = antibodies in the blood🩸
• End zone = nervous system
• Points in the end zone = antibodies in the spinal fluid
Before we discuss this in relation to testing for EPM, lets answer some questions:
• Are there always defenders on the field? No – but once they’ve seen the offense they are!
• Are there always points in the end zone? No
• How do we know if the offenders have crossed into the endzone? Points!
When we test for EPM we have 3 options:
1. We can find the organism. The organism is in the nervous system (brain and spinal cord). The only way to find it is necropsy, which is not ideal for future riding purposes. This is the only 100% confident way of diagnosing EPM. 💯
2. We can find evidence that the body has seen the organism. We look for evidence that CC has seen the Plymouth offense and has built a defense to fight them. We test antibodies in the blood. This is a “serum titer”.🩸
o If the defenders are there, has Plymouth crossed into the endzone? Not necessarily!
o If the antibodies are there, has the EPM organism made it to the nervous system? Not necessarily!
3. We can find evidence that the nervous system has seen the organism. We look for evidence that the Plymouth offense has crossed into the endzone (points). We test antibodies in the spinal fluid. This is a “CSF titer”.
o If there are points, has Plymouth crossed into the endzone? Yes
o If there are antibodies in the spinal fluid, has the EPM organism crossed into the nervous system? Yes
So lets go back to our questions from above:
o Are there always antibodies in the blood? No – but once they’ve seen the EPM organisms they are!
o Are there always antibodies in the CSF? No
o How do we know if EPM organisms have crossed into the nervous system? Look for antibodies in the CSF
Is it halftime yet? 🤕
The moral of the story is, we rarely get the opportunity to do a necropsy to confidently test for EPM. But looking only at serum titers does not tell us very much either! The best way to accurately diagnose a horse with EPM is to look at CSF titers. Basing a diagnosis on serum titers only leads to inaccurate, and consequently delayed, diagnosis on neurologic horses, as well as unnecessary treatment. There are several techniques to collect spinal fluid (CSF), one of which is a standing cervical centesis (see image below). This procedure is done under the same sedation many horses have received before for dentals, sheath cleaning, etc. The correct spot is identified with an ultrasound, and a needle poke later, fluid is collected. As far as the horse is concerned, its no more traumatic than a blood draw.
So after all that….make sure you’re advocating for an accurate diagnosis for your horse. If EPM is a concern, please pursue a CSF tap. If you need help or more information, just reach out to us!
Also, GO EAGLES!!🦅🏈
**Going back in my football free bubble** 🙃
Also, who do I talk to about making CSF and nervous system emojis?
