Flea-Borne Diseases

Laurie Anne Walden, DVM

Fleas don’t just cause itching. They also carry infectious diseases that can be contagious to people. Controlling fleas on your pets protects your whole family’s health.
 
Tapeworms
Tapeworms are parasites that live in the intestines. They shed small body segments called proglottids that pass out of the host animal’s body in the feces. Tapeworm segments in the stool look like whitish rice grains.
 
Fleas transmit a type of tapeworm that commonly infects dogs and cats. Dogs and cats become infected by swallowing a flea. Tapeworms rarely cause significant disease in dogs and cats.
 
The dog and cat tapeworm that is carried by fleas, Dipylidium caninum, can also infect humans (usually children) who swallow a flea.[1]
 
Bartonellosis (Cat Scratch Disease)
Bartonella species are bacteria that cause a variety of diseases in humans and other animals. Cat scratch disease and endocarditis (heart valve infection) are just 2 of the serious illnesses caused by Bartonella infection.[2]
 
Fleas are the most common insect vector for Bartonella henselae, the species that causes cat scratch disease.[3] Fleas can also carry other Bartonella species. Infected cats and dogs might or might not have any symptoms of infection.
 
Bartonellosis is a human health risk. Treating your cat with a cat-safe flea preventive reduces the risk of cat scratch disease for people in contact with your cat.
 
Rickettsial Diseases
Rickettsiae are a group of bacteria responsible for diseases such as typhus and Rocky Mountain spotted fever. Rickettsiae are spread by arthropods, including fleas and ticks. The types of fleas that infest dogs and cats transmit Rickettsia typhi (which causes murine typhus) and Rickettsia felis. Both of these bacteria can also cause disease in people.[1,4]
 
Yersiniosis (Plague)
Plague, including bubonic plague and the Black Death, is caused by infection with the bacterium Yersinia pestis. The Oriental rat flea (Xenopsylla cheopis) transmits the bacterium usually to rodents but sometimes to cats, dogs, other animals, and humans. Rat fleas in the western United States and other parts of the world still harbor Yersinia.[3]
 
Mycoplasma Infection
Cats infected with certain types of Mycoplasma bacteria develop anemia (low red blood cell count). Fleas are thought to be a source of infection for cats.[5]
 
Noninfectious Diseases
Fleas cause skin disease in animals that scratch or chew themselves to relieve the itch. Just a few fleas can set off intense itching in an animal with a flea allergy.
 
Because fleas feed on blood, animals with lots of fleas can develop anemia from blood loss. This anemia can be life threatening.
 
References
1. Fleas. Companion Animal Parasite Council website. https://capcvet.org/guidelines/fleas/. Updated September 19, 2017. Accessed May 7, 2019.
2. Bartonella infection (cat scratch disease, trench fever, and Carrión’s disease). Centers for Disease Control and Prevention website. https://www.cdc.gov/bartonella/index.html. Updated December 14, 2015. Accessed May 7, 2019.
3. Shaw SE. Flea-transmitted infections of cats and dogs. World Small Animal Veterinary Association World Congress Proceedings, 2008. Veterinary Information Network website. https://www.vin.com/doc/?id=3866578. Accessed May 7, 2019.
4. Little SE. Feline fleas and flea-borne disease (proceedings). DVM360 website. http://veterinarycalendar.dvm360.com/feline-fleas-and-flea-borne-disease-proceedings. Published April 1, 2010. Accessed May 7, 2019.
5. Lappin MR. Update on flea and tick associated diseases of cats. Vet Parasitol. 2018;254:26-29.
 
Photo of Oriental rat flea (Xenopsylla cheopis) by James Gathany, CDC

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