Hartmannella

[härt′mə-nĕlə]
n.
  1. A free-living ameba commonly found in soil, sewage, and water and known to invade invertebrates such as snails and oysters; it is considered to be a causative agent of primary amebic meningoencephalitis.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.