Equine protozoal myelitis in Panamanian horses and isolation of Sarcocystis neurona.

The article discusses the identification of a parasite, Sarcocystis neurona, in Panamanian horses showing symptoms of equine protozoal myelitis (EPM). It also outlines the successful laboratory cultivation of the parasite from a spinal cord sample.

Parasite Identification in Panamanian Horses

• The researchers used microscopic examination to identify Schizonts of Sarcocystis neurona in the spinal cord tissue of Panamanian horses.
• These particular horses were exhibiting clinical signs of equine protozoal myelitis (EPM), a debilitating neurological disease affecting horses.

Isolation and Laboratory Cultivation of Sarcocystis neurona

• Spinal cord homogenate from another Panamanian horse with EPM was inoculated onto monolayers of cultured bovine monocytes, a type of white blood cell.
• At 13 weeks post-inoculation, intracellular parasites called schizonts, containing progeny parasites or merozoites arranged in specific rosette patterns surrounding a central residual body, were observed.
• The parasites were seen to multiply using a method known as endopolygeny.
• Notably, these parasites lacked organelles called rhoptries that are typically present in certain classes of parasites.

Immunohistochemical Test

• Immunohistochemistry, a method of detecting antigens or proteins in cells of a tissue, was used as a further validation test.
• The schizonts from each horse reacted with the Sarcocystis cruzi antiserum, confirming their identification.