A species of gram-negative bacteria that is the causative agent of human EHRLICHIOSIS. This organism was first discovered at Fort Chaffee, Arkansas, when blood samples from suspected human ehrlichiosis patients were studied.
A plant genus of the family POACEAE that many people consider to be a weed.
A tribe of gram-negative bacteria of the family RICKETTSIACEAE whose organisms are found in arthropods and are pathogenic for man and certain other vertebrate hosts.