Parasites in Cats

Parasites in cats are fairly common, though with quick detection they can be treated without causing harm to your favorite feline. A parasite is an organism that lives off of or inside another organism, called a host, during all or part of its life. This is a type of symbiotic relationship in which the parasite needs the host in order to live. The parasite obtains nourishment and/or protection from its host. A parasite may or may not harm the host, but the host never benefits from the parasite. There are many types of organisms considered to be parasites, including some plants, animals, spiders, crustaceans, bacteria and worms. 


While not all cats show symptoms of parasites, it's imortant to know what they are. Some of the most common symptoms of cats with parasites are:

  • Weight Loss
  • Decrease in Appetite
  • Lethargy
  • Vomiting
  • Diarrhea
  • Protruding Belly


Whipworms are another type  of parasite. Cats can contract whipworms (Trichuris trichura) into their system through ingestion of infested matter. Whipworms are able to live in most any environment from a few months to a few years. 


Tapeworm infections can affect your cat by settling in the small intestine. An invasion  by the Cestoda tapeworm often results  in a medical condition referred to as Cryptosporidiosis. 


Bartonellosis is an  infectious bacterial disease caused by the gram-negative bacteria Bartonellosis hanselae. It’s commonly known as Cat Scratch Disease(CSD), or "cat scratch fever." This is a zoonotic disease, meaning that it can be transmitted between animals and humans. In cats, the disease is generally transmitted through contact with flea feces. The bacterium is excreted through the flea and into its feces, which it leaves on the cat's skin. The cat, through grooming itself, ingests the bacteria, thereby becoming infected with the Bertonella strain. It’s important to note that this bacterial infection can also be a conduit for passing the disease,  such as when an infected cat licks a skin abrasion or open wound on a human.


Babesia is a disease caused by the protozal (single-celled)  parasites of the genus Babesia. The most common contraction method is by the tick bite, as the Babesia parasite uses the tick as a reservoir to reach host mammals. An infection may occur in your cat by contraction through a tick. This can happen by direct transmission via blood transfer from dogs or cats. There are some cases where these are not diagnosed for months to years.


Botflies are flies that are of the genus Cuterebra. They are found in the Americas, where they are obligatory parasites of rodents and rabbits. The botflies proliferate by laying eggs on blades of grass or in nests. 

It's important to watch for the symptoms of parasites in cats in order to detect and treat quickly. When you're aware of your cat's regular behaviors and watch for changes in those behaviors, you can help your vet diagnose parasites quickly. Early detection and the proper treatment is the way to get your cat back its old self again.