Dictionary.net

• A genus of protozoans: endoparasitic and probably pathogenic.

1898 - American pocket medical dictionary
By Willam Alexander Newman Dorland

• Syn. : Herpetomona and Prowazekia. A genus of the phylum Mastigophora and family Herpetomonida of the Protozoa, being elongated, wedge-shaped, flagellated organisms, sometimes parasitic, in the intestine of domestic flies.

1916 - Appleton's medical dictionary
By Smith Ely Jelliffe