One year old female opossum at Witter Wildlife Refuge.
Photo by Author
Words For Wildlife by State licensed Wildlife Rehabilitator, James Orr
OPOSSUM CAN CAUSE PROBLEMS FOR HORSES
I have written a couple of articles on Opossums and pointed out several amazing and positive facts bout them. Since their body temperature is too low to support rabies they are relatively harmless to people but they can pose a health threat to horses.
Opossums and birds have been identified as the primary carriers of a disease called Equine Protozoal Myeloencephalitis (EPM). This disease does not effect the possum as it is carried in the intestines but it can be very harmful to horses. The disease is an infection of the central nervous system of the horse that can lead to a great many problems including lameness, airway abnormalities, and severe back soreness to name a few.
EPM is passed to horses via possum and bird feces which can be tracked by the feet or tail of the possum walking in a feeding trough or climbing on feed piles. Dr. Fenger* speculates most horses probably ingest the EPM sporocysts, mount an immune response, and clear the organisms before they reach the central nervous system. For those that do contract the disease it can manifest itself over many years. There is no dormant period and there is no remission.
There are currently no FDA approved drugs for treatment of EPM but there are a number of “off-label and imported drugs from other countries that are effective and legal.
If you have horses it is recommended that you make your feed supply possum proof. Anything that attracts possums into horse barns should be tightly covered especially at night. This includes cat food, garbage and grain. Feed should not be left out at night.
The possum population around barns and stables can be kept under control by a number of methods. Wire mesh around the outside with a “hot wire” may keep possums out as they climb but do not dig. Possums can be “live trapped” fairly easily using apples, oatmeal cookies, or peanut butter for bait with minimal risk of trapping domestic animals. Some wildlife rescuers will help you trap and relocate possums.
There have been cases where horses completely isolated from possible host contamination still contracted the disease indicating it had been passed to them from their feed which must have been contaminated at the packaging plant. The process of steam-crimping and pelleting grain kills off sporocysts, so using processed grains can decrease exposure the EPM.
*Information reported above is based largely on excerpts from a PhD dissertation by Clara K. Fenger, DMV, PhD, DACVIM for the University of Kentucky. You can learn more about EPM on the internet. Using the Yahoo server and simply typing EPM. Their are numerous articles several of which address the possum connection.
For Wildlife Emergencies Call 677-3039. The Game and Fish Commission also lists other licensed rehabilitaors in the State.
DONATIONS NEEDED If you would like to help any donation amount it is greatly appreciated. Donations should be made out to Witter Wildlife Refuge and can be sent to P.O. Box 1118, Huntsville AR 72740.
See web page under "HOW YOU CAN HELP" for specific ways you can help us help wildlife
