Fleas: More Than Just A Bite

Pet owners’ main concern when it comes to fleas is obvious: flea bites that leave the pet itchy and uncomfortable. However, fleas are more than just an itch! Fleas can actually carry many different parasites and infectious diseases as well as cause some non-infectious illnesses, putting your pet at risk for more than just some scratching.

Some examples of common flea-related health issues include:


This parasite is the most common side effect of flea infestations that we see. This happens when a flea carrying tapeworm eggs is ingested by your pet, most often from grooming or licking and chewing at their itchy body. Once the eggs are swallowed, they hatch and make themselves comfortable in the gastrointestinal tract, feeding off of the nutrients the animal consumes. Tapeworms don’t always cause clinical signs, so you may not know your pet is affected until you see what looks like small white grains of rice in their feces. Sometimes you may also see scooting or, in severe cases, weight loss and a poor coat.

Cat Scratch Disease

Bartonella henselae is a bacteria that is estimated to be carried by 40% of cats at some point in their lifetimes and can also affect dogs and humans. It is transmitted via flea feces (or “flea dirt”) that is deposited on the animal’s body and licked off during grooming. Most cats that have Bartonella do not show symptoms, although some will develop a fever for 2-3 days and in rare cases, may have vomiting, diarrhea, or swollen lymph nodes. These cats do however put their owner at risk for infection of “Cat Scratch Fever”. A cat with Bartonella in their system can transmit the bacteria to you via bite, lick or scratch. In humans, Bartonella can cause fever, headaches, and fatigue. It is especially dangerous for those with an already weakened immune system.

Feline Infectious Anemia

Mycoplasma haemofelis is a parasitic bacteria that is transmitted through flea bites, as well as via ticks and mosquitoes, and can affect both cats and dogs. This bacteria attaches to the animal’s red blood cells, causing the body to detect the blood cells as foreign and want to destroy them. Once a large number of red blood cells are destroyed by the body, the animal will become anemic, which can cause symptoms such as weakness, lethargy, pale gums, weight loss, fever, jaundice, and enlarged lymph nodes.

Flea Allergy Dermatitis

All flea bites will be itchy and irritating, but some dogs and cats actually have an allergy to flea saliva and experience much worse irritation. The allergic reaction can often lead to skin infections or “hot spots,” commonly seen at the base of the tail or on the bottom half of the pet.


Because fleas feed on your pet’s blood, there is a risk for your pet to become anemic from blood loss. This is usually only seen in small puppies and kittens, sickly animals, or in extremely severe infestations that go untreated. Symptoms include pale gums, low body temperature and lethargy.

For more information on fleas and how to prevent and treat an infestation, please see our previous blog: https://www.vetcarepethospital.ca/fleas-what-you-need-to-know/

Written by Stephanie, RVT