orange kitten

What a shock I had last Thursday! I saw my Maine Coon Thor having a hair ball on the bathroom floor. When I went in to clean it up, there were 2 long worms in the vomit – cat parasites. Ewwww!

Cats become part of our families, sharing our homes and lives. But along with the purrs and cuddles, they might bring in some unwelcome guests—parasites.

These tiny invaders, ranging from the commonly known fleas and ticks to the less visible but equally troublesome internal parasites like worms and protozoa, pose significant health risks not just to our feline friends but potentially to us as well.

Understanding the variety of parasites that can affect cats and the way they're transmitted is the first step in protecting both the health of our pets and our own, especially considering some of these parasites can cross species and affect humans.

Key Takeaways

There are many cat parasites.

These include worms, protozoa and “ectoparasites”, like fleas, ticks and mites.

Monitoring your cat for symptoms, routine vet visits and prevention strategies are important ways to keep your cat healthy.

Types of Cat Parasites


Roundworms, such as Toxocara cati and Toxascaris leonina, are common intestinal parasites in cats. Infected felines may shed eggs through their feces, posing a risk of infection to other animals and, in rare cases, humans.


Hookworms, especially Ancylostoma species, are small yet dangerous parasites that reside in the intestinal tract. They can penetrate the skin or be ingested from contaminated soil.


Tapeworms are segmented worms typically acquired through the ingestion of fleas or rodents carrying tapeworm larvae. You may notice these segments, which resemble grains of rice or sesame seeds, near your cat's rear end or in their bedding.



Heartworms are transmitted through mosquito bites, making any outdoor exposure a risk for infection.

Unlike in dogs, heartworm in cats often goes undiagnosed until serious symptoms, such as a chronic cough or difficulty breathing, affect the lung and heart health. Regular vet visits and preventive medication are your best defense.


Protozoan parasites can cause conditions like giardiasis, coccidiosis, and toxoplasmosis. These single-celled organisms typically infect the gastrointestinal tract, leading to symptoms like diarrhea.

Adequate water sanitation and hygiene practices are important to reduce their spread.


Giardia cysts


Ectoparasites such as fleas, ticks, and various mites infest the exterior of your cat's body, often leading to skin irritation and discomfort. Regular check-ups and the use of topical or oral preventatives are essential in keeping these opportunistic pests at bay.

cat with vet

Common Symptoms and Diagnosis of Cat Parasites

Gastrointestinal Issues

Parasites like roundworms or tapeworms commonly affect your cat's gastrointestinal tract. You might notice vomiting, frequent diarrhea, or a loss of appetite, which can lead to weight loss.

Respiratory Problems

Respiratory signs including a persistent cough may indicate parasites like lungworms have infected the lung tissues.

Dermatological Signs

Your cat's skin can show various signs of parasitic infections, such as hair loss and skin irritations,

Neurological Disorders

Parasitic infections can sometimes lead to neurological symptoms like seizures or behavior changes in your cat.

Transmission and Life Cycle

Direct Transmission

Parasites that affect cats can be transmitted directly through direct contact with infected feces or soil. For instance, if your cat ingests infective Toxoplasma gondii eggs from contaminated soil or feces

Indirect Transmission

roundworm life cycle

Some parasites require an intermediate host for their development. For example, larvae residing in an infected rodent or flea could become infective to your cat if they consume the flea or rodent.

Similarly, cysts of parasites like Giardia may be transmitted from host to host through water, potentially impacting both indoor and outdoor cats.

Prevention and Control Strategies

Hygiene and Sanitation

Maintaining good hygiene is key in preventing the spread of cat parasites. Regularly clean your cat's living area and any spaces they frequent. This includes:

  • Litter boxes: Scoop feces daily and change litter weekly to minimize the risk of parasitic eggs contaminating the environment.
  • Bedding: Wash your cat's bedding in hot water weekly to kill any potential parasites or eggs.
cat and vet

Protective Medications

A range of protective medications can safeguard your cat against parasites:

  • Dewormers: Use dewormers to protect against internal parasites.
  • Flea and tick prevention: Apply topical preventatives or use oral medications to shield your cat from fleas and ticks.
  • Heartworm prevention: Administer heartworm preventatives as prescribed by your vet.

Environmental Measures

The environment your cat lives in can either contribute to or reduce the risk of parasite infestations:

  • Indoor vs. Outdoor: Restrict your cat's outdoor access to reduce exposure to wildlife and environmental sources of infestation.
  • Infestation control: Implement strategies to control any existing infestations immediately to prevent reinfection.

Treatment and Management

cat with vet

Deworming Protocols

For successful treatment, it's crucial to identify the type of parasite present through a diagnosis made by your vet.

Subsequently, the recommended deworming process involves the administration of medication specifically tailored to eradicate the parasites. This can require a single dose or a series of doses depending on the severity of the infestation.

Remember that an accurate medication adjustment may be necessary over time, which your vet can determine based on the results of follow-up tests.

Monitoring and Follow-Up

Regular monitoring of your cat after treatment is key. This involves both observing your cat's behavior and condition, as well as scheduling follow-up visits to your vet for professional assessment.

During this period, your vet may perform additional tests to confirm the parasites have been completely eradicated and to decide if further medication adjustment is warranted.

The Follow up

Well, it turns out my cat had roundworms. It's a mystery because my cats never go outside. So Thor got treated at the vet. I picked up additional doses for my other 2 cats. It's an easy-to-give liquid that goes on their skin between the shoulder blades. 

Now to wait 3-4 weeks and bring in poop samples to make sure all the worms are gone.


How can you identify and treat worms in felines?

You can identify worms in felines by looking for symptoms such as vomiting, diarrhea, weight loss, or visible worms in the stool or around the anus. Treatment typically involves anti-parasitic medications prescribed by a veterinarian.

What are the common symptoms of internal parasites in cats?

Common symptoms of internal parasites in cats include vomiting, diarrhea, blood in stool, a swollen abdomen, and lethargy. If you notice these signs, it is important to consult a veterinarian for diagnosis and treatment.

Are feline parasites transferable to humans, and how can this be prevented?

Yes, some feline parasites are transferable to humans, a condition known as zoonosis. To prevent this, practice good hygiene, keep your cat's living environment clean, and have regular check ups.

What is the most prevalent type of parasitic infection in cats?

Toxoplasmosis, caused by the Toxoplasma gondii parasite, is one of the most prevalent parasitic infections in cats, affecting their nervous system and sometimes spreading to humans.

How are external parasites on cats effectively treated?

External parasites, such as fleas, ticks, lice, and mites, are effectively treated using topical treatments, oral medications, and sometimes shampoos or dips designed to kill these pests.

Can feline parasites be contagious to other household cats or pets?

Yes, many feline parasites are contagious to other household cats and pets. Maintaining a scheduled deworming program and keeping your pet's living area clean can help minimize the risk of transmission

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