Figure 14-82.

Sarcocystis Neurona, Brain, Horse.

S. neurona is a small, crescent-shaped to round protozoan microbe found in neurons, endothelial cells, and microglial cells. The microbes can be arranged in nonencysted aggregates (arrow) or rosettes intracellularly and in central nervous system tissue often with a mixed leukocytic cellular inflammatory response of varied severity. Microbes can be difficult to detect in histologic sections. H&E stain.

(Courtesy Dr. J. Simon, College of Veterinary Medicine, University of Illinois.)