1. EPM Equine Protozoal Myeloencephalitis Samantha Pettus

2. Primary Hosts Intermediate hosts: raccoons, rats, cats, skunks, otters, and armadillos. These hosts contract the disease and carry it. Definitive host: opossum, this host contracts the disease by eating the carcasses of the intermediate hosts. Dead end host: horse, this host contracts the disease by ingesting opossum feces.

3. Pathogen EPM is caused by a parasite called Sarcocystis nuerona.

4. Environmental and Management conditions that favored the pest originally. Horses contract this disease by ingesting opossum feces. The horse may come in contact with the feces through hay, water, or feed in which an opossum may have come in contact with. The best way to ensure that horses do not get EPM is to ensure that hay is stored in a secure location, that grain bins are tightly sealed, and that water is kept clean.

5. Best Controls Anti-protozoal drugs Anti-inflammatory drugs such as Banamine Exercise can help to strengthen the muscles, retain damaged spinal tracts, and enhance healing of the nervous system. Massage therapy. Special shoeing or shaping of the hooves to adjust weight distribution so that the horse can learn to hold its weight again.

6. Why was I interested in this disease? When I worked at Jatona Lane Farm a group of our horses contracted EPM from a batch of bad hay. Out of the 5 horses that got the disease only one pulled through.

7. Symptoms and Clinical Signs of EPM Weakness, dropping feed, lameness, slight gait asymmetry of rear legs, muscle atrophy, and spasms.

8. Experiment One Experimental Induction of Equine Protazoal Myeloencephalitis (EPM) in the Horse: Effect of Sarcocystis Neurona Sporocyst Inoculation Dose on the Development of Clinical Neurologic Disease

9. Experiment One What and Why: This experiment tests the effects of Sarcocystis neurona on the development of EPM in horses. Not all horses that contract EPM develop the symptoms of the disease, the reason for this is unknown due to the lack of research, this experiment tests different possible reasons for the development of symptoms.

10. Experiment One How: Twenty four weaned horses were subjected to the stress of transportation. They were randomly assigned into 6 groups with 4 horses per group. Each group was given different doses of S. nuerona and one group was given placebo. The horses were examined weekly for 4-5 weeks. After the experiment the horses were euthanized and their bodies were examined.

11. Experiment One Tables: GroupHorse no.SexBreed Seroconversio n CSF Ending neurological examination score (masked) DFS A 40MBelgianNegative122 7FBelgianNegative0none 36MQH/ BelgNegative0none 27MBelgianNegative2.58 B 5MBelgianNegative2.515 41MBelgianNegative2.522 18FBelgian4Positive2.515 4MBelgian5Positive222 C 14MBelgian4Positive2.58 12MBelgian4Positive222 37MBelgian4Negative222 19FBelgian3Negative2.522 D 23MBelgian3Positive222 21FBelgianNegative1.529 13MBelgian3Positive1.529 8FBelgian4Positive229 E 11MBelgian3Positive115 10FBelgian3Positive28 30MBelgian3Positive28 17FBelgian3Positive0none F 39MBelgian2Positive28 24MBelgian2Positive2.58 29MQH/ Belg2Positive222 3FBelgian2Positive2.58 GroupHorse no. Number of Sarcocystis neurona sporocysts fed. A7,27,36,40NONE B4,5,18,4110^2 C12,14,19,3710^3 D8,13,21,2310^4 E10,11,17,3010^5 F3,29,34,3910^6

12. Experiment One In this experiment the horses were given a dose of S. neurona pathogen, then these horses were closely monitored and protected from any natural cause of the disease. In the field horses may be subjected to the disease multiple times. The trial horses were also protected from stress as much as possible, where as horses in the field may be subjected to the stress of ambient noises, weather, and etc…

13. Experiment Two Horse Experiemtnally Infected with Sarcocystis neurona Develop Altered Immune Responses in Vitro.

14. Experiment Two What and Why: This article studied whether horses that were experimentally infected with EPM would show suppressed immune responses. It is unknown why EPM effects some horses differently than others, this article researches and tests how different horses will react to S. neurona.

15. Experiment Two How: Thirteen horses that were S. neurona negative were chosen. 5 horses were placed in a control group, the other 8 were placed in an infected group. The horses were monitored for 48 day.

16. Experiment Two Graphs:

17. Percentage of CD8 cells of total lymphocytes following overnight stimulation with merozoites. Percentage of CD8 cells of total lymphocytes producing IFN- gamma when stimulated with merozoites.

18. Experiment Two In this experiment the experimentally infected horses showed the same altered immune function responses as naturally infected horses. This is important because with further research the results from this experiment can be used to detect EPM before symptoms arise. This experiment may also help in the development of a treatment that can directly target S. neurona cells.

19. Cites The Horse Your Guide to Equine Health Care http://www.thehorse.com/articles/10301/rehabilitating-the-epm-horse American Association of Equine Practitioners http://www.aaep.org/info/horse-health?publication=752 Equine Protozoal Myeloencephalitis http://www.epmhorse.org/The_Disease/Opossum.htm Experimental Induction of Equine Protozoal Myeloencephlitis (EPM) in the Horse: Effect of Sarcocystis neurona Sporocyst Inoculation Dose on the Development of Clinical Neurologic Disease. Horses Experimentally Infected with Sarcocsist neurona Develop Altered Immune Responses in Vitro.