Avoid A Cat-astrophe!

Gastrointestinal parasites are common in cats; more common than people are aware. According to Cornell University College of Veterinary Medicine, the number of household cats who have had or currently have parasites sits around the 45% mark. That’s almost half of the pet cat population! The most common parasites can be worm-like (roundworm, hookworm and tapeworm) or single-celled organisms (coccidia, giardia and toxoplasma). I will be focusing on the worm-like parasites for this month’s blog.

Many cats who have parasites don’t show any outward signs of the infestation. Other cats have non-specific clinical signs such as coughing, poor hair coat, vomiting, diarrhea, blood in the stool, mucus in the stool, poor appetite and/or a pot-bellied appearance. Worms can lead to serious health concerns if the vomiting and diarrhea cause dehydration. Parasites can also weaken the cat’s immune system, which will make the cat susceptible to other types of infection and illness. Some parasites are also transmissible to people!


These worms are the most common intestinal parasite of the cats we see at the clinic. The adult roundworm is beige and between 8-12.5 cm (3-5 inches). An adult roundworm looks kind of like a spaghetti noodle. Cats become infected with this worm through their mother, or by eating rodents or bugs that carry the worms in their body tissues. They can also become infected by ingesting the eggs in the infected soil. The prevalence of this parasite is extremely high in kittens (because of the transmission from mother cat). While most roundworm infections are not dangerous to the cat’s health, roundworm infections can become life-threatening if the worm numbers are so high that the intestines get blocked.Roundworm

You typically do not see these parasites with the naked eye. Sometimes when the parasite burden is so large, a cat may vomit a worm or pass a worm in the stool, but that isn’t very common. Diagnosis is formed by mixing fresh stool with fecal flotation liquid and looking at the mixture under the microscope to check for eggs. Treatment is easy and very effective.

This parasite has the potential to be transmitted to humans. Visceral larval migrans (VML) and ocular larval migrans (OLM) are conditions caused by the migration of the roundworm larva through human body tissues. These diseases primarily occur in children. Although these diseases are quite rare, they can be severe. It is important to deworm your cat regularly, ideally prevent your cat from hunting outside and prevent children from being exposed to cat feces.


Hookworms are small, slender worms that are ~1.25 cm (~1/2 inch) in length and they live in the intestinal tract of the cat. Hookworms live for quite a long time and are capable of living for as long as the cat. This type of worm is not as commonly found as roundworms, but hookworm infestations are quite prevalent in the Sudbury area. Infection usually occurs when the hookworm larva is ingested or penetrates the cat’s skin. Hookworms are voracious eaters, and severe infection can lead to anemia from blood loss in the intestines where the hookworms attach. Death is possible from a heavy hookworm burden.

As with roundworms, you do not see this worm in the feces and the eggs of this parasite, as they are microscopic. Diagnosis is made the same way as with roundworm, and hookworm treatment is very effective. Twice daily litter box cleaning is often the key to controlling hookworm infestations.

As in the case of cats, these parasites can penetrate the human skin, so there is potential for human infestation as well. The worm migrates under the skin, which causes the tissues to become inflamed and infected. This condition is called cutaneous larval migrans (CLM). Proper sanitation techniques (i.e., hand washing and cleaning the environment around the litter box) are recommended when your household cat has been diagnosed with hookworm.


Tapeworms are worms with flattened segmented bodies, each segment of the tapeworm is filled with eggs. The adult tapeworm lives in the intestine with its small head buried in the tissues. As the tapeworm matures, the segment farthest from the head break off and are passed in the cat’s feces. These segments can be seen with the naked eye in the stool, or around the cat’s tail and rectal area. The segments are small in length, flat and look like grains of rice when fresh or like sesame seeds when dried out.

Cats contract tapeworm from fleas or rodents. Fleas and rodents become infected by eating tapeworm eggs in the environment. Cats get fleas and ingest them while grooming, or ingest the rodents during hunting and become infected with tapeworm. Diagnosis by fecal flotation is usually not effective because the eggs are not passed individually, but rather as a packet of eggs in a segment. Most diagnoses occur during the physical exam by your veterinary or by the owners, who notice the tapeworm segments around the rectum. Treatment for tapeworm is extremely successful, but re-infection is common. The use of flea prevention medication appropriate for cats helps prevent tapeworm infection. Repeat treatment multiple times a year for cats who hunt regularly is recommended.

Using a regular deworming schedule and flea prevention in conjunction can reduce the likelihood of a “cat-astrophe” from these parasites! Call us today to discuss how you can treat and prevent these parasites from affecting your cat.

Written by Shanon Chase, RVT