Types of Intestinal Parasites in Cats
There are several common types of intestinal parasites that can affect cats:
Roundworms
Roundworms (Toxascaris leonina and Toxocara cati) are among the most common intestinal parasites in cats, affecting 25% to 75% of cats, with higher rates in kittens (https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/gastrointestinal-parasites-cats). Roundworms look like spaghetti and can grow up to 7 inches long in a cat’s intestines. Kittens can pick up roundworms in the womb, through nursing, or by ingesting eggs from the environment.
Tapeworms
Tapeworms (Dipylidium caninum and Taenia taeniaeformis) are also common intestinal worms in cats. They latch onto the intestinal wall and absorb nutrients from the cat. Tapeworm segments look like rice grains and can sometimes be seen around a cat’s anus or in their stool. Cats get tapeworms from ingesting fleas or small mammals infected with tapeworm larvae.
Hookworms
Hookworms (Ancylostoma tubaeforme) are less common but can cause more severe disease, including bloody diarrhea and anemia from blood loss. Cats get hookworms from ingesting larvae from contaminated soil or the mother’s milk. The hookworms attach to the intestinal lining and feed on blood.
Whipworms
Whipworms (Trichuris vulpis) are also less common parasites that live in the cecum, the beginning of the large intestine. They can cause chronic watery diarrhea, weight loss, and anemia. Cats ingest whipworm eggs from contaminated soil or feces.
Giardia
Giardia is a single-celled protozoal parasite that can cause foul-smelling diarrhea. Cats get Giardia from ingesting contaminated feces or water sources containing the parasite cysts. Giardia damages the intestinal lining, causing malabsorption.
Coccidia
Coccidia (Isospora felis, Isospora rivolta) are protozoal parasites that most often affect kittens and cats with weakened immune systems. Ingested cysts damage the intestinal lining, causing watery diarrhea, weight loss, and abdominal pain. Kittens often pick up coccidia from nursing or grooming an infected mother cat.
Symptoms of Intestinal Parasites
Intestinal parasites can cause a variety of symptoms in cats. Some of the most common symptoms include:
- Diarrhea – Parasites irritate the intestinal tract and can cause inflammation, leading to loose, watery stool. Giardia in particular is known for causing acute diarrhea.
- Vomiting – Some parasites directly irritate the stomach and upper GI tract, causing vomiting. Roundworms are a common culprit.
- Weight loss – Parasites rob the body of nutrients, which can lead to weight loss even while maintaining appetite. Tapeworms especially can cause weight loss.
- Dull coat – The parasite infection diverts nutrition away from the skin and coat, leading to a dull, brittle coat.
- Pot belly appearance – Certain parasites like roundworms and whipworms live in the intestines, causing gas and a distended belly.
If a cat is exhibiting any of these symptoms, intestinal parasites may be the cause. Diagnostic testing is needed to confirm the presence of parasites.
Diagnosing Intestinal Parasites
There are a few main diagnostic tests veterinarians use to check for intestinal parasites in cats:
Fecal Exam/Flotation Test: This is the most common diagnostic test. A fecal sample from the cat is mixed with a solution that causes parasite eggs to float to the top where they can be examined under a microscope. This test can detect roundworm, hookworm, whipworm, and other intestinal parasites. (source)
Tapeworm Segments in Stool: Tapeworm infections can sometimes be diagnosed by visually inspecting the cat’s stool and looking for tapeworm segments, which resemble grains of rice. If tapeworm segments are seen, it confirms the presence of an active tapeworm infection. (source)
Blood Tests: Blood tests can sometimes detect the presence of certain parasites through antibodies or other changes in blood cell counts. However, blood tests are not as accurate as fecal exams for intestinal parasites. They may be used to supplement fecal exams. (source)
Treating Roundworms and Hookworms
The most commonly prescribed medications for treating roundworm and hookworm infections in cats are:
- Fenbendazole (https://vcahospitals.com/know-your-pet/roundworm-infection-in-cats)
- Pyrantel pamoate (https://vcahospitals.com/know-your-pet/roundworm-infection-in-cats)
- Milbemycin oxime
Fenbendazole and pyrantel pamoate work by paralyzing the worms’ muscles, causing them to detach from the intestinal lining so they can be expelled from the body. Milbemycin oxime also paralyzes worms, but works by blocking their neurotransmitters.
These dewormers are given orally, either in pill form or liquid form. The medication causes the worms to detach and be expelled through the stool. Normally more than one dose is needed, given 2-3 weeks apart, to fully eliminate the infection. This ensures any migrating or newly hatched worms are killed as well.
It’s important to follow your veterinarian’s prescribed dosage and treatment schedule. Give all doses even if you no longer see worms in the stool. Stopping treatment early can allow immature worms to reach adulthood and continue the infection. With appropriate deworming, roundworms and hookworms can be fully treated.
Treating Tapeworms
Tapeworms are segmented parasites that live in the small intestine of cats and attach to the intestinal wall. There are several medications used to treat tapeworms in cats:[1]
Praziquantel is one of the most common and effective medications used to treat tapeworms in cats. Praziquantel tablets are given orally and work by paralyzing the tapeworms, allowing them to detach from the intestinal lining so they can be eliminated from the body. Praziquantel is highly effective at treating both Dipylidium caninum and Taenia species of tapeworms.
EPS tablets contain praziquantel as well as epsiprantel and pyrantel pamoate, allowing the medicine to treat tapeworms and also hookworms and roundworms. These combination tablets are convenient if your cat has multiple intestinal parasites.
Niclosamide is another medication that can be used to get rid of tapeworms in cats. Niclosamide works by inhibiting the tapeworm’s ability to use glucose, causing the parasite to let go of the intestinal wall. Niclosamide is often used as a second treatment if praziquantel alone did not eliminate the tapeworm infection.[2]
Treating Whipworms
There are a few medications that can be used to treat whipworm infections in cats:
Fenbendazole is often the first line treatment. It is given orally over the course of 3-5 days. Fenbendazole works by preventing the worms from absorbing nutrients, essentially starving them. Some common trade names for fenbendazole are Panacur and Safe-Guard.
Febantel is another deworming medication used for whipworms. It paralyzes the worms so they detach from the intestines and get expelled from the body. It is often combined with pyrantel and praziquantel in dewormers like Drontal. Treatment is a single oral dose which makes it convenient.
Piperazine is effective at treating roundworms and hookworms as well as possibly whipworms. It works by paralyzing the worms so they detach from the intestinal lining. Since the efficacy against whipworms is lower, it is not typically the first choice. Liquid piperazine like PipaTab is given orally once a day for 7-14 days.
In some cases, different medications may be combined or rotated to fully eliminate whipworms. It’s important to follow up with repeat fecal tests to ensure the parasites have been cleared.
Some heartworm and flea prevention medicines also contain agents effective against whipworms. However, a vet should still prescribe appropriate deworming medication to start. Prevention alone may not fully eliminate an existing infection.
Treating Giardia
Giardia is a common intestinal parasite in cats that can cause diarrhea. There are several medications that are effective for treating giardia in cats:
Fenbendazole is often prescribed at a dose of 50 mg/kg once daily for 5 days to kill the giardia parasites. Fenbendazole is given orally and is safe for use in cats. Research shows it is effective for clearing giardia infections (Source).
Metronidazole is another common treatment given at a dose of 25 mg/kg twice daily for 5 days. Metronidazole is an oral medication that is well-absorbed and able to kill giardia throughout the intestinal tract (Source).
Tinidazole is also sometimes used and has been shown in studies to eliminate giardia. It is given as a one time oral dose. Tinidazole may be preferred in some cases because it requires only a single treatment (Source).
Typically one of these three medications will be prescribed after diagnosis to effectively treat giardia infections in cats. Treatment may need to be combined with probiotics and a bland diet during recovery.
Treating Coccidia
Coccidia is a common parasitic infection in cats that affects the intestinal tract. It is caused by microscopic organisms called coccidian parasites. There are several medications that can be used to treat coccidiosis in cats:
Sulfadimethoxine is one of the most commonly prescribed antibiotics for treating coccidia. It is from the sulfa-class of antibiotics and goes by the brand name Albon®. The usual treatment protocol is to give this medication daily for 5-20 days based on the severity of infection. Sulfadimethoxine is effective at killing the coccidia organisms.
Ponazuril is another medication used to treat coccidiosis in cats. It goes by the brand name Marquis®. Ponazuril is highly effective against coccidian parasites by disrupting their cellular function. It is given as a single dose and then a second dose 2-4 weeks later. Ponazuril requires a prescription from a veterinarian.
Toltrazuril is also used to treat coccidia infections in cats. The brand name is Baycox®. Like ponazuril, it works by interfering with the cellular metabolism of coccidian parasites. Toltrazuril is given as a single dose initially and then another dose 2 weeks later. It is highly effective but also requires a prescription from a veterinarian.[1]
In most cases, coccidia can be successfully treated with medications like sulfadimethoxine, ponazuril or toltrazuril. Severe infections may also require supportive fluid therapy if a cat becomes dehydrated. With prompt treatment, the prognosis for full recovery is very good.
Prevention of Reinfection
Preventing reinfection after treating intestinal parasites is crucial. parasites, and prevent re-exposure in the future.
Some tips for prevention include:
- Regular deworming as recommended by your veterinarian. Certain intestinal parasites can reinfect a cat quickly, so consistent deworming is key.
- Proper litter box hygiene – feces should be scooped out of litter boxes daily and boxes cleaned regularly to remove parasite eggs and cysts.
- Avoid exposure to feces – clean any feces in the home environment immediately to prevent spread.
- Wash hands after handling cats or cleaning litter boxes to prevent human transmission of certain parasites like Toxoplasma.
With diligent prevention methods, reinfection can be minimized and your cat’s health protected.
When to See a Vet
In most cases, intestinal parasites can be treated at home with over-the-counter or prescription medications from your veterinarian. However, there are some situations when you should take your cat to see the vet right away:
Severe Symptoms – If your cat is showing signs of severe dehydration, bloody stool, vomiting, or lethargy, take them to the vet immediately for evaluation and treatment. Severe symptoms can be life-threatening.
Kittens/Older Cats – Kittens and older cats may be more susceptible to complications from intestinal parasites due to their still-developing or compromised immune systems. Bring them in for prompt vet care.
Weakened Immune System – Cats with feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), or other illnesses affecting the immune system are at higher risk for parasite infections becoming severe. Seek vet attention quickly.
Treatment Not Working – If you’ve been treating your cat for intestinal parasites but their symptoms persist or worsen, take them to the vet for further diagnostics and treatment options. The parasites may be resistant to medication.
Bring a fresh fecal sample with you to the vet appointment so they can analyze it for parasite eggs and determine the best course of treatment. Prompt vet care for severe cases of intestinal parasites can help get your cat back to health.