Definition

Noun: 1. A genus of bacteria: A taxonomic category (genus) of small, rod-shaped, or coccoid bacteria. These bacteria are obligate intracellular parasites, meaning they can only live and reproduce inside the cells of a host organism. 2. Pathogenic microorganisms: Members of this genus are notable for being the causative agents of several significant vector-borne diseases in humans. They are primarily transmitted by arthropods such as ticks, lice, fleas, and mites.

Usage Examples

• Noun:
  • The bacterium Rickettsia rickettsii, a member of the genus Rickettsia, is responsible for Rocky Mountain spotted fever.
  • Scientists study the genus Rickettsia to understand how these pathogens evade the human immune system.
  • Diagnosis of diseases caused by the genus Rickettsia often requires specialized laboratory tests.

Advanced Usage

• Taxonomic Context: In scientific writing, the name is often italicized () when referring to the genus, and the first letter is capitalized. When used as a common noun (e.g., "a rickettsia"), it is not italicized and is often lowercased, referring to any bacterium within the genus.
  • The Rickettsia were observed inside the host cell. (Referring to the genus)
  • This disease is caused by a rickettsia. (Referring to a type of bacterium)

Variants and Related Words

• Rickettsial (adj): Of or relating to bacteria of the genus .
  • The patient was treated for a rickettsial infection.
• Rickettsiosis (n): Any disease caused by bacteria of the genus .
  • Typhus is a form of rickettsiosis.

Synonyms

• Rickettsiae (n, plural): A common term for bacteria belonging to this genus.
• Obligate intracellular bacterium: A descriptive term for its biological characteristic.

Related Terms and Context

• Vector-borne pathogen: A key descriptive phrase, as organisms in the genus Rickettsia are spread by vectors.
• Typhus group / Spotted fever group: Clinical and taxonomic classifications for diseases and species within the genus, such as (epidemic typhus) and (Rocky Mountain spotted fever).

Noun

1. can cause typhus and Rocky Mountain spotted fever in humans