rickettsia

noun

rick·​ett·​sia ri-ˈket-sē-ə 

plural rickettsias or rickettsiae ri-ˈket-sē-ˌē 

-ˌī

also rickettsia

: any of a various gram-negative, parasitic bacteria (order Rickettsiales and especially genus Rickettsia) that are transmitted by biting arthropods (such as lice or ticks) and cause a number of serious diseases (such as Rocky Mountain spotted fever and typhus)

Note: Rickettsia are often pleomorphic, and may be coccoid, rod-shaped, or irregularly-shaped.

rickettsial

ri-ˈket-sē-əl 

adjective

Examples of rickettsia in a Sentence

Recent Examples on the Web

Tidewater fever, or rickettsia parkeri, is a form of Rocky Mountain spotted fever. —Michael Reschke, Indianapolis Star, 23 Dec. 2019

Ticks can transmit a variety of diseases such as Borrelia burgdoferi, also known as Lyme disease, and Rickettsia rickettsia that can cause Rocky Mountain Spotty Fever. —Gabriela Moraru, M.d., miamiherald, 4 June 2018

Word History

Etymology

New Latin, genus name, from Howard T. Ricketts †1910 American pathologist

First Known Use

1916, in the meaning defined above

Kids Definition

rickettsia

noun

rick·​ett·​sia rik-ˈet-sē-ə 

plural rickettsias or rickettsiae -sē-ˌē 

-sē-ˌī

: any of various bacteria including several that cause diseases (as Rocky Mountain spotted fever and typhus) in human beings

rickettsial

-sē-əl 

adjective

Medical Definition

rickettsia

noun

rick·​ett·​sia ri-ˈket-sē-ə 

1

capitalized : a genus of rod-shaped, coccoid, or diplococcus-shaped often pleomorphic bacteria (family Rickettsiaceae) that are transmitted by biting arthropods (as lice or ticks) and cause a number of serious diseases (as Rocky Mountain spotted fever and typhus)

2

plural rickettsiae -ˌē  also rickettsias or rickettsia : any bacterium of the genus Rickettsia, the family Rickettsiaceae, or the order Rickettsiales