Flea Borne Rickettsias

Rickettsial diseases are caused by bacteria from the genus Rickettsia. Humans become infected with flea-borne Rickettsia through the infectious bite of a flea or through infectious flea fecal material. At Alameda County Vector Control, we concentrate on monitoring two Rickettsia species:

• Rickettsia typhi:
  • The causative agent of flea-borne typhus, also known as murine typhus
  • It is spread from the bite or feces of an infected Oriental rat flea (Xenopsylla cheopis)
  • Severe illness may develop in humans, but fatalities are rare
• Rickettsia felis:
  • A likely human pathogen  
  • Symptoms may include fever, fatigue, and rash; no deaths or serious complications have been reported

In 2020, the Alameda County Vector Control District began a surveillance program targeting flea-borne Rickettsial disease by collecting fleas from different host animals throughout the County. The District’s disease surveillance focuses on two flea species:

• The cat flea (Ctenocephalides felis)
• This is the primary flea species associated with domestic animals and urban wildlife
• The cat flea is the host for pathogens such as Rickettsia felis
• The Oriental rat flea (Xenopsylla cheopis)
• The main host is the Norway rat, which maintains the disease cycle of Rickettsia typhi, the causative agent of murine typhus

The best way to avoid flea-borne diseases is to avoid being bitten by fleas. Refer to our Fleas page for more information on how to avoid being bitten and exposed to fleas.