AN EQUINE PROTOZOAL MYELOENCEPHALITIS CHALLENGE MODEL TESTING A SECOND TRANSPORT AFTER INOCULATION WITH SARCOCYSTIS NEURONA SPOROCYSTS

• Published in: The Journal of parasitology 2004-12, Vol.90 (6), p.1406-1410
• Main Authors: Saville, W. J A, Sofaly, C. D, Reed, S. M, Dubey, J. P, Oglesbee, M. J, Lacombe, V. A, Keene, R. O, Gugisberg, K. M, Swensen, S. W, Shipley, R. D, Chiang, Y-W, Chu, H. J, Ng, T
• Format: Article
• Language: English
• Subjects: abiotic stress; animal pathology; animal stress; animal transport; Animals; Antibodies; Autopsy - veterinary; Biological and medical sciences; Biological Assay - veterinary; Disease; disease models; Encephalomyelitis; Encephalomyelitis - parasitology; Encephalomyelitis - pathology; Encephalomyelitis - physiopathology; Encephalomyelitis - veterinary; equine protozoal myeloencephalitis; Female; Fundamental and applied biological sciences. Psychology; General aspects; General aspects and techniques. Study of several systematic groups. Models; Horse Diseases - parasitology; Horse Diseases - pathology; Horse Diseases - physiopathology; Horses; Hypotheses; infection; Infections; Inoculation; Invertebrates; Lesions; Male; Mice; Mice, Knockout; Model testing; Nervous system diseases; Neurologic examination; Neurologic Examination - veterinary; Neurologic manifestations; Numbering schemes; oral infection; Parasitology; PATHOLOGY; Random Allocation; Sarcocystis - pathogenicity; Sarcocystis neurona; Sarcocystosis - pathology; Sarcocystosis - physiopathology; Sarcocystosis - veterinary; Seroconversion; Spinal cord; Sporocysts; sporocysts (Protozoa); Stress, Physiological - complications; Stress, Physiological - immunology; Stress, Physiological - veterinary; symptoms; Time Factors; transport stress; Transportation
• ISSN: 0022-3395; 1937-2345
• DOI: 10.1645/GE-128R

Previous challenge studies performed at Ohio State University involved a transport-stress model where the study animals were dosed with Sarcocystis neurona sporocysts on the day of arrival. This study was to test a second transportation of horses after oral inoculation with S. neurona sporocysts. Horses were assigned randomly to groups: group 1, transported 4 days after inoculation (DAI); group 2, at 11 DAI; group 3, at 18 DAI; and group 4, horses were not transported a second time (controls). An overall neurologic score was determined on the basis of a standard numbering system used by veterinarians. All scores are out of 5, which is the most severely affected animal. The mean score for the group 1 horses was 2.42; group 2 horses was 2.5; group 3 horses was 2.75; and group 4 horses was 3.25. Because the group 4 horses did not have a second transport, they were compared with all other groups. Statistically different scores were present between group 4 and groups 1 and 2. There was no difference in the time of seroconversion between groups. There was a difference between the time of onset of first clinical signs between groups 1 and 4. This difference was likely because of the different examination days. Differences in housing and handling were likely the reason for the differences in severity of clinical signs. This model results in consistent, significant clinical signs in all horses at approximately the same time period after inoculation but was most severe in horses that did not experience a second transport.