Migrogliosis
Severity Grade 1 (minimal)	Microgliosis barely exceeds normal limits; it is typically focal and/or sporadic and of no biological relevance; it is a common change in control animals, especially monkeys
Severity Grade 2 (mild)	Microgliosis more readily apparent than minimal severity grade, typically focal or multifocal; typically a level of severity uncommonly encountered in controls
Severity Grade 3 (moderate)	Microgliosis readily apparent; typically focally extensive or multifocal and typically a level of severity uncommonly encountered in controls
Severity Grade 4 (marked)	Microgliosis pronounced, affecting a prominent portion of a given brain/spinal cord region, typically at a level of severity not encountered in controls
Severity Grade 5 (severe)	Microgliosis very pronounced, affecting a prominent portion of a given brain/spinal cord region, typically at a level of severity not encountered in controls