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

Definition of 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.

Other Words from rickettsia

rickettsial \ ri-​ˈket-​sē-​əl How to pronounce rickettsia (audio) \ 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 example sentences are selected automatically from various online news sources to reflect current usage of the word 'rickettsia.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of rickettsia

1916, in the meaning defined above

History and Etymology for rickettsia

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

Learn More About rickettsia

Time Traveler for rickettsia

Time Traveler

The first known use of rickettsia was in 1916

See more words from the same year

Dictionary Entries Near rickettsia

rickets

rickettsia

rickettsia body

See More Nearby Entries 

Statistics for rickettsia

Cite this Entry

“Rickettsia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/rickettsia. Accessed 7 Dec. 2021.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon

More Definitions for rickettsia

rickettsia

noun
rick·​ett·​sia | \ ri-ˈket-sē-ə How to pronounce rickettsia (audio) \

Medical Definition of rickettsia

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

More from Merriam-Webster on rickettsia

Britannica.com: Encyclopedia article about rickettsia

WORD OF THE DAY

Test Your Vocabulary

Difficult Spelling Words Quiz

  • alphabet pasta spelling help
  • Which is the correct spelling?
True or False

Test your knowledge - and maybe learn something along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!