Currently, no vaccine is available to protect against EPM. For now, your best bet for preventing EPM lies in limiting your horse’s exposure to the protozoa. And, for the most part, that means taking steps to break the parasite’s life cycle and to prevent opossums from contaminating your horse’s feed and water:
• Avoid attracting large numbers of scavengers. It is not necessary, or probably even possible, to keep all opossums
away from your property. And that’s OK: Opossums eat prodigious numbers of pest species, including mice and ticks, which can also carry diseases. But you do want to keep their numbers to a minimum---and that means closing down the food sources on your farm that would attract opossums and encourage them to stick around.
Keep your feed in sealed containers and clean up spills immediately. Use sturdy garbage cans with tight-fitting lids. Pick up uneaten cat and dog food at the end of each day, and clean up fallen seed under bird feeders. If you have fruit trees, pick up fallen fruit. Killing or trapping opossums won’t help---if you’re still providing food sources, more will come.
• Pick up animal carcasses. Opossums pick up S. neurona by scavenging carcasses of other infected animals---which can be many species, including skunks, raccoons, armadillos and cats. To reduce the risk that local opossums will get infected, remove any dead wildlife you may find on your property.
• Keep hay and bedding clean. Make an effort to keep any roving opossums away from your horse’s feed and bedding. Store these materials in a secured shed or loft to keep out wild animals, and dispose of any you find that has been contaminated with animal feces. Use feeders to keep hay off of the ground; check them periodically for animal wastes and clean as needed.
• Seal off the shelters. Clear up brush piles, which can provide shelter for wildlife, and close doors to sheds and other outbuildings, especially at night. Close off access to spaces underneath buildings, too---but first make sure you don’t already have animals in residence. You don’t want to trap them inside.
• Limit your horse’s stress. Horses who travel frequently and undergo the stresses of training and competing in high-intensity sports are at greater risk of developing EPM, according to a 2000 study from Ohio State University. Your veterinarian can advise you on steps to avoid overtaxing your competition horse and to keep him generally healthy.
For more information, go to “On the Frontlines Against EPM” (EQUUS 451).
With no EPM vaccine currently available, your best bet for protecting your horse is limiting your horse’s exposure to the causal protozoa.