Intestinal Parasites That Cause Weight Loss in Cats

The American Veterinary Medical Association and VetInfo4Cats.com report that there are several different types of intestinal parasites common to cats. Intestinal parasites generally turn a cat's small or large intestine into their home; however, some parasites may also infect the respiratory tract or heart. Parasites are transmitted through several avenues, including infected water and feces, from a mother to her kittens or the ingestion of an infested rodent.

  1. Giardia

    • Giardia cati can move effectively in a cat's small intestine.

      According to Doctor Foster and Smith's Pet Education.com, "Giardia are protozoa (one-celled organisms) that live in the small intestine of cats and dogs." When a cat eats the cyst form of this organism, it releases its active form, trophozoite, into the animal's small intestine. Able to move very effectively inside the intestine, the parasite attaches itself to the cat's intestinal wall and begins to reproduce, disabling the cat's ability to garner nutrition from its food and damaging the intestinal lining. While the cat may not lose its appetite when infected with the giardia cati parasite, the animal will begin to lose weight.

    Hookworms

    • Hookworms are common in kittens.

      A common and frightening internal parasite, hookworms are especially prevalent in kittens. These toothy nibblers come in four different classifications; however, only the A. tubaeforme, A. braziliense and U. stenocephala infect cats. Using their "teeth-like structures or cutting plates," as Pet Eduction.com terms, hookworms affix themselves to the cat's intestine and begin to feed off of their blood. Not only does this cause serious conditions such as anemia and diarrhea, but hookworms might also be responsible for unexplained weight loss in the cat. In fact, seriously infected cats run the risk of dying from emaciation caused by hookworms.

    Roundworms

    • Roundworms can be spread from cats to humans.

      Another common internal parasite is the roundworm. Also known as ascarids, two of three classifications (Toxascaris leonina and Toxocara cati) favor cats as their host. Roundworms are extremely contagious and pose a threat to both other animals and humans. If infested, a cat can pass millions of roundworm eggs in their fecal matter daily. Many monthly topical flea and tick applications also prevent roundworms. Pet Education.com recommends that if a cat becomes infested, it should be monitored and have fecal testing performed regularly once treatment is complete to ensure reinfestation does not occur.