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Flea-Borne Typhus

May contain: animal, insect, invertebrate, and flea

Flea-borne typhus, formerly called murine typhus, is a bacterial disease found primarily in the fleas that live on animals such as cats, dogs, opossums, rats, and other backyard wildlife and is transmitted by fleas. Flea-borne typhus is caused by the bacteria Rickettsia typhi and Rickettsia felis, present in fleas and flea feces.

Fleas defecate as they feed. Infection occurs when flea feces containing the bacteria are scratched into the bite site, other wounds, inhaled, eaten, or transferred to the eye (conjunctiva).

Even though cats, dogs, opossums, rats, and backyard wildlife may be infected, they do not show obvious symptoms. These animals are infested with fleas year-round in Orange County. Fleas do not survive without the presence of a host animal. Pet animals should be kept on flea-control medication year-round.

May contain: person and human
Images showing Typhus Transmission Cycle

Flea-borne typhus is transmitted by fleas found on:

  • Feral and domestic cats
  • Dogs
  • Opossums
  • Rats
  • Raccoons
  • Skunks
  • Squirrels
  • Rabbits
  • Any mammal that infested with fleas.

How Will I Know If My Pet Has Fleas?

Fleas found on pets can be infected with flea-borne typhus. Fleas are active all year in Orange County. Flea control is the best way to prevent exposure to flea-borne typhus. 

Even indoor only animals can become infested with fleas.  Regularly inspect pets and pet bedding for fleas. The presence of flea feces in pet fur, called “flea dirt”, may be the first sign of a flea infestation. Pet owners should keep pets up-to-date on a flea control and heartworm preventative program.

Pets and backyard wildlife can be infested with fleas that transmit flea-borne typhus to humans. The animals may or may not become infected. Pets and backyard wildlife are hosts for fleas.  Fleas do not survive without the presence of a host animal.