rickettsia

noun

rick·​ett·​sia ri-ˈket-sē-ə How to pronounce rickettsia (audio)
plural rickettsias or rickettsiae ri-ˈket-sē-ˌē How to pronounce rickettsia (audio)
-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 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

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'rickettsia.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

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

First Known Use

1916, in the meaning defined above

Time Traveler
The first known use of rickettsia was in 1916

Dictionary Entries Near rickettsia

Cite this Entry

“Rickettsia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rickettsia. Accessed 22 Jul. 2024.

Kids Definition

rickettsia

noun
rick·​ett·​sia rik-ˈet-sē-ə How to pronounce rickettsia (audio)
plural rickettsias or rickettsiae -sē-ˌē How to pronounce rickettsia (audio)
-sē-ˌī
: any of various bacteria including several that cause diseases (as Rocky Mountain spotted fever and typhus) in human beings
rickettsial adjective

Medical Definition

rickettsia

noun
rick·​ett·​sia ri-ˈket-sē-ə How to pronounce rickettsia (audio)
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 How to pronounce rickettsia (audio) also rickettsias or rickettsia : any bacterium of the genus Rickettsia, the family Rickettsiaceae, or the order Rickettsiales

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