EPM Flashcards
What was the initial name for EPM identified by Rooney in 1970?
Segmental Myelitis
What is the primary cause of EPM?
Sarcocystis neurona
Which protozoan is less commonly implicated in EPM cases compared to S. neurona?
Neospora hughesi
Who are the definitive hosts for Sarcocystis neurona?
Opossums in North America and various South American opossums
Name some intermediate hosts for Sarcocystis neurona.
Skunks, raccoons, armadillos, and cats.
Where does sexual reproduction of Sarcocystis neurona occur in opossums?
In the intestinal epithelium.
What do sporozoites form in intermediate hosts?
Latent sarcocysts in muscle tissue
How do horses become infected with Sarcocystis neurona?
By ingesting food or water contaminated with feces from an infected opossum
Why are equine carcasses seldom accessible to opossums?
To reduce the likelihood of horses contributing to the parasite’s life cycle.
Is vertical transmission of Sarcocystis neurona common in horses?
No, it is considered uncommon despite antibodies being detected in foals before suckling.
How does Sarcocystis neurona likely enter the CNS?
Through infection of endothelial cells or leukocytes.
Is the complete life cycle of Neospora hughesi known?
No, it remains poorly understood.
Are dogs confirmed definitive hosts for Neospora hughesi?
No, it has not been established.
Can Neospora hughesi be transmitted transplacentally in horses?
Yes, recent studies suggest it can be transmitted transplacentally.
Are all horses susceptible to EPM?
Yes, but not all infected horses develop clinical disease.
What have studies in mice and horses shown about the immune response to Sarcocystis neurona?
They demonstrated a critical role for the immune response in preventing disease.
Do all horses with EPM show the same immune response?
No, some show altered immune responses which are sometimes antigen-specific.
What factors may influence the progression to severe neurologic disease in EPM?
Variations in protozoal inoculum and stress-induced immune suppression.
Did efforts to increase stress and treatment with immunosuppressive steroids consistently lead to increased disease severity?
No, they did not consistently lead to increased disease severity.
Has genetic variation been observed among strains of Sarcocystis neurona?
Yes, some strains may be particularly virulent, though not confirmed in horses.
What percentage of EPM cases occurred in horses aged 4 years or less?
61.8%.
What was the mean age of affected horses?
3.6 ± 2.8 years.
Which breeds are most commonly affected by EPM?
Thoroughbreds, Standardbreds, and Quarter Horses.
Was there any significant sex or seasonal bias found in EPM cases?
No significant sex or seasonal bias was established.