Educational Articles

Cats + Parasites

  • Heartworms are a blood-borne parasite called Dirofilaria immitis that reside in the heart or adjacent large blood vessels of infected animals. There is no drug approved for treating heartworms in cats. Veterinarians now strongly recommend that all cats receive year-round monthly heartworm preventative in areas where mosquitoes are active all year round.

  • Hookworms are intestinal parasites of the cat and dog. Their name is derived from the hook-like mouthparts they use to anchor themselves to the lining of the intestinal wall. They are only about 1/8" (two to three mm) long and so small in diameter that they are barely visible to the naked eye.

  • Lung flukes in North America are parasites called Paragonimus kellicotti that infect the lungs of cats after they have eaten an infected crayfish or rodents that have eaten infected crayfish. Eggs are then released by the parasite into the cat’s sputum to be coughed out or swallowed and released in the feces to continue the life cycle. Lung flukes can be found anywhere in North America but more commonly around the Mississippi River and Great Lakes. Infected cats can be symptom-free or may develop cough with sometimes bloody mucus, pneumonia, pneumothorax, lethargy and weakness. Diagnosis can include locating eggs of the parasite from feces or mucus from the lungs. X-rays can also reveal cysts in the lungs caused by the parasite. Treatment requires one of 2 commonly used anti-parasitic medications: Praziquantel or Fenbendazole. Although zoonotic, these parasites won’t transmit directly from cats to humans.

  • Roundworms are one of the most common intestinal parasites of the cat. They can be an important cause of illness, even death, in kittens. As their name implies, these are large-bodied round worms, averaging about 3-6 inches (8-15 cm) in length. They do not attach to the wall of the intestine, as some intestinal parasites do. Instead, they are literally "swimming" freely within the intestine.

  • Tapeworms are intestinal parasites of the cat and dog. They are classified as cestodes. They belong to a different family than hookworms and roundworms, which are the other common intestinal parasites of dogs and cats. Several types of tapeworms are known to infect cats. Dipylidium caninum is by far the most common species observed in cats.

  • Ticks are parasites that feed on the blood of their host and can in turn transmit diseases to your cat or even you. They are prolific breeders and their life cycles can extend through multiple seasons. Prompt removal or use of preventatives limit or prevent the spread of disease, or kill the ticks.

  • Toxoplasmosis is a disease caused by infection with the organism called Toxoplasma gondii (T. gondii). This is a microscopic single-cell protozoal organism related to coccidia. Virtually all warm-blooded animals, including people, can be infected with this organism. It is an extremely well adapted parasite and rarely causes significant disease to the individuals it infects.