7 Symptoms of Intestinal Parasites in Cats

Intestinal parasites in cats are a common problem, causing symptoms that can make your kitty feel anywhere from uncomfortable to miserable.

Any cat can get intestinal parasites, but young kittens and older cats with weakened immune systems are most susceptible. Nearly all kittens are born with intestinal parasites, and the parasites’ larvae (immature life stage) can lie dormant within a cat’s body, causing reinfection later in life.

Unfortunately, these troublesome parasites aren’t going anywhere anytime soon. Let’s review the most common intestinal parasites in cats, what symptoms they cause, and how a monthly parasite preventative like Revolution Plus or NexGard COMBO can help treat and control them.

Types of Intestinal Parasites in Cats

Intestinal parasites in cats are either worms (such as roundworms) or protozoans (Giardia), which are single-celled organisms.

The parasites migrate to a cat’s digestive system, setting up shop in the small intestine. 

Here are the common types of intestinal parasites in cats:


Roundworms, also known as ascarids, are about 2–3 inches long and are the most common cat intestinal parasite. Cats can get them by eating soil or feces infected with roundworm eggs. Transmission can also occur from mom to her unborn kittens, as well as through nursing. Roundworms can become abundant enough in the gut to cause intestinal blockage. 


Hookworm larvae burrow through a cat’s skin. They can also be transmitted in utero, during nursing, and by eating infected rodents. The worms use their sharp mouthparts to latch onto the small intestinal wall and suck the host’s blood.


Cats commonly get tapeworms by eating infected fleas. Eating infected prey, such as rodents and birds, can also cause tapeworm infections in cats. These worms consist of segments called proglottids that contain eggs and look like white grains of rice when passed in a cat’s poop. Like roundworms, they can multiply enough in the gut to block the intestines.


Giardia is a protozoan that is transmitted through contaminated food and water. Due to many cats not showing any symptoms, pet parents may not realize that their cat has giardia.


Coccidia is another protozoan that lives in the small intestine. It is transmitted from mom to kitten during nursing or by ingesting feces from infected wildlife.

Roundworms, hookworms, and giardia are zoonotic, meaning they can be passed from pets to people. For example, roundworms are passed to humans via ingestion of worm eggs that hatch into larvae while in the body. Most of the time, no symptoms occur. However,  roundworm infections in humans can sometimes lead to tissue or nerve damage, or even ocular larva migrans, during which the worm larvae migrate to the eye and can cause irreversible blindness.

7 Symptoms of Intestinal Parasites in Cats

Intestinal parasites, given their location, cause several gastrointestinal symptoms. However, systemic symptoms can also occur. Here are a few symptoms of intestinal parasites in cats to watch for.


Diarrhea is seen with each intestinal parasite described above, resulting from disrupted digestion and nutrient absorption. Diarrhea is bloody with hookworms, and diarrhea from giardia is often watery and profuse, and contains mucus. Tapeworm infections may cause mild diarrhea.


Vomiting is typically seen with roundworms and Giardia.


A pot-bellied appearance is characteristic of a roundworm infection. This appearance occurs when the worms multiply so much in the gut that the abdomen physically expands. 

Weight loss

Weight loss can occur with each of the intestinal parasites because of appetite loss and general gastrointestinal upset.

Poor growth

Poor growth is seen in kittens infected with intestinal parasites. The parasites are essentially “stealing” nutrients from the kitten that are essential for normal growth and development.


Coughing is seen with a roundworm infection. After initial infection, the roundworm larvae travel up to the lungs, where they are coughed up and then swallowed. They then reach the small intestines, where they mature into adults.

Pale gums

Hookworm infection causes pale gums because of the blood loss caused by the worms sucking the host’s blood in the small intestine. Pale gums indicate anemia, which can be severe and fatal in young infected kittens.

Other than the potbelly, the symptoms listed here are not specific to intestinal parasites. These symptoms can be found with many other diseases, including other gastrointestinal diseases (e.g. inflammatory bowel syndrome) and diseases of other body systems, such as the respiratory system.

Also, infections with intestinal parasites do not always cause symptoms. For example, many cats with hookworms do not show any outward signs of infection. However, if your young kitten has any of these symptoms, intestinal parasites are a probable culprit.

Cat Intestinal Parasites: Next Steps

If you think your cat has an intestinal parasite, take them to your veterinarian for examination and diagnostic testing.

A fecal exam is the primary way to diagnose intestinal parasites. A fresh fecal sample (no more than 24 hours old) is ideal. Collect a sample from your cat and refrigerate it until your appointment. If you’re understandably squeamish about keeping your cat’s poop in your fridge, try to collect a sample before leaving for the appointment.

If you can’t get a sample at home, your veterinarian will collect one during the appointment.

Your veterinarian will perform a fecal float, in which the feces are mixed with a solution that makes the parasite eggs float to the top of the solution. The liquid is then examined under a microscope.

Giardia and tapeworms are difficult to detect on a fecal exam. Tapeworms are typically diagnosed by seeing the tapeworm segments around a cat’s anus.

Treatment for intestinal worms is with a dewormer medication. Your veterinarian will prescribe the most appropriate dewormer for the type of intestinal worm infecting your cat. 

Be aware that deworming medications kill only adult worms. Therefore, if an infected cat has worm larvae, those larvae may lie dormant and cause reinfection later.

Giardia is treated with antibiotics. However, treatment is difficult because reinfection is common and often associated with stress.

Preventing Intestinal Parasites in Cats

Deworming young kittens is a mainstay of intestinal parasite prevention. Kittens are typically dewormed every two weeks, from 3 to 4 weeks of age until about 3 months of age. Kittens are then dewormed monthly until 6 months of age.

Here are other prevention strategies:

Keep your cat indoors. Keeping your cat indoors will prevent them from eating infected soil, feces, and prey. 

Schedule regular fecal exams. Fecal exams are a routine part of your cat’s wellness exams. Regular fecal exams will help your veterinarian identify intestinal parasites and, if needed, prescribe the most appropriate treatment.

Administer year-round, broad-spectrum parasite prevention. Parasite prevention isn’t just important in the warmer months. Your cat will need year-round prevention to be effectively protected from intestinal parasites.

Prevent fleas. Yes, indoor cats can get fleas! A year-round flea preventative is critical to preventing fleas and subsequent tapeworm infections.

Ask your veterinarian what type of parasite preventative is best suited for your cat. To provide protection against a variety of parasites, consider a broad-spectrum product like Revolution Plus or NexGard COMBO. Simply apply one dose of the topical solution to your cat’s skin once a month to kill fleas and ticks, prevent heartworm disease, and treat and control roundworms and hookworms. NexGard COMBO also includes tapeworm coverage.

NexGard COMBO for cats packaging

Preventing the Passage of Parasites to People

Additionally, it’s important that you take extra precautions to avoid getting infected with the intestinal parasites that can be passed to people.

Promptly get rid of feces. Young children are at high risk of infection with these parasites because they touch almost anything and put their fingers in their mouths. Remove your cat’s feces as soon as possible, and don’t forget to wash your hands immediately after.

Avoid contaminated food and water. Do not drink water that may be contaminated or eat food that was rinsed in contaminated water.

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