Viral infections

JC virus (leading to progressive multifocal

leukoencephalopathy

Human adenovirus

Cytomegalovirus

Herpes simplex I and II

Varicella zoster

Epstein-Barr

Nonviral infections

Toxoplasmosis

Cryptococcosis

Candidiasis

Histoplasmosis

Coccidioidomycosis

Aspergillus

Neurosyphilis