Is Your Cat’s Tapeworm Hitching a Ride? The Risks of Zoonotic Parasites


Tapeworms are segmented intestinal parasites that belong to the flatworm class Cestoda. There are several different species of tapeworms that can infect cats, dogs, and humans. The most common tapeworm species found in cats are Dipylidium caninum and Taenia taeniaeformis.

Tapeworms live in the small intestine and attach themselves to the intestinal wall using hook-like mouthparts or suckers. As adult tapeworms mature inside a host, they shed segments filled with eggs that are passed in the feces. This is how tapeworms spread between hosts.

Although tapeworm infection is generally harmless in cats, there are risks of transmission to humans that can cause more serious effects. This article provides an overview of the common tapeworm species in cats, how infection spreads to humans, the effects and diagnosis in humans, and prevention methods.

How Cats Get Tapeworms

Cats become infected with tapeworms when they ingest fleas carrying tapeworm larvae or eat infected rodents. Tapeworm eggs are ingested by flea larvae as they feed on organic debris or the infected feces of rodents. Once inside the flea, the tapeworm egg hatches into a larva and develops into an infective cysticercoid. When a cat grooms itself and swallows an infected flea, the tapeworm is released from the cyst and attaches itself to the cat’s small intestine using hook-like mouthparts.

Eating infected rodents such as mice or rats is another way tapeworms are transmitted to cats. The rodents ingest tapeworm eggs, which develop into larvae in their tissue. When a cat eats the infected rodent, it becomes a new host for the tapeworm.

In addition, mother cats can pass tapeworms to nursing kittens. Larvae in the mother’s intestine will migrate to the mammary tissue and be transmitted through her milk to the kittens. This is why deworming kittens and nursing mother cats is important.


Species of Tapeworms in Cats

The most common tapeworm species found in cats are:
Dipylidium caninum,
Taenia, and Echinococcus.

Dipylidium caninum, also known as the common flea tapeworm, is the most prevalent tapeworm in cats. It is transmitted by ingesting fleas carrying the tapeworm larvae. This species can grow up to 20 inches long in a cat’s intestine.

Taenia tapeworms have multiple species that can infect cats, including Taenia taeniaeformis and Taenia serialis. These are transmitted by ingesting rodents carrying the tapeworm larvae. Taenia tapeworms are long flat worms that can reach up to 10 feet in length inside a cat!

Echinococcus, though less common, can also infect cats that hunt and ingest rodents carrying the larvae. This parasite targets the liver and forms fluid-filled cysts.

Transmission to Humans

Tapeworms are transmitted to humans when they accidentally ingest infected fleas. Cats become infected with tapeworms after eating infected fleas or small animals that have eaten infected fleas. These tapeworms produce egg capsules which are passed in the cat’s feces or shed from their body. Fleas become infected when they ingest these tapeworm eggs while grooming or feeding on an infected cat. If an infected flea is ingested by a human, either directly or through contact with an area contaminated with infected flea feces, they can become infected with tapeworms.

According to the CDC, the two tapeworm species that can be transmitted to humans from cats are Dipylidium caninum and Taenia taeniaeformis. Dipylidium caninum is the most common feline tapeworm species transmitted to humans. Infection occurs when people accidentally swallow an infected flea, often due to inadequate hygiene after contacting pets or areas contaminated with flea feces. The risk of human infection is low but possible if infected flea larvae are accidentally ingested.


Effects in Humans

Most of the time, tapeworm infections in humans cause no symptoms. When symptoms do occur, they are usually mild and non-specific. According to the Mayo Clinic, the most common symptom from tapeworm infection is mild abdominal pain and digestive issues such as nausea, diarrhea, and abdominal cramping.

Tapeworms absorb nutrients from the food you eat, which can sometimes lead to weight loss, increased appetite, or vitamin deficiencies over a long period of time. However, these symptoms are quite rare.

Some species of tapeworm have been known to cause more severe symptoms. For example, the pork tapeworm can form cysts in body tissues outside the digestive tract, which could potentially lead to organ damage or neurological issues if left untreated. But again, severe symptoms are very uncommon with most tapeworm species that infect cats and humans.

Overall, a tapeworm infection usually produces minimal to no symptoms in humans. Mild digestive upset may occur in some cases, but serious health effects are extremely rare (Mayo Clinic, 2022).

With proper diagnosis and treatment, tapeworm infections are not considered dangerous or life-threatening for humans.

Diagnosis in Humans

Diagnosing a tapeworm infection typically begins with a visual inspection of the stool. Doctors will look for telltale signs of infection like eggs, larvae, or segments of the worm. Stool samples are checked under a microscope to identify tapeworm eggs or proglottids.

Tapeworm eggs can appear clear, yellowish, or golden brown. Proglottids, which are egg-filled segments of the tapeworm’s body, look like small pieces of white rice. Seeing either eggs or proglottids in the stool is diagnostic of an intestinal tapeworm infection.

Doctors may also order blood work, MRI, CT scan, or ultrasound imaging to check for cysts or larvae in other parts of the body like the eyes, brain, or muscles. These tests can determine if the infection has spread beyond the intestines.

In some cases, an endoscopy or colonoscopy may be performed to view the intestinal lining and look for adult tapeworms. A biopsy may be taken of suspicious lesions.

Overall, a stool sample test is the most common way to diagnose a tapeworm infection. Detecting eggs or proglottids provides clear evidence that tapeworms are present and treatment is needed.

Treatment for Humans

The most common treatment for tapeworm infection in humans is the drug praziquantel, which is an oral medication. This medication is very effective at killing tapeworms. Praziquantel causes the tapeworm to dissolve within the intestines, allowing it to pass in the stool. The medication is taken as a single dose and works quickly, killing the adult tapeworms typically within hours.

According to the Mayo Clinic, taking praziquantel eliminates over 80% of tapeworms (source). Some people may need additional doses if the infection was severe. Side effects are generally mild, such as headache, dizziness, nausea, vomiting, and abdominal discomfort.

In some cases, other anti-parasitic medications may be prescribed, such as niclosamide or nitazoxanide. Albenza is another common anti-tapeworm medication. The doctor will determine the best medication and dosage regimen based on factors like the patient’s age, health status, and specifics of the infection.

In addition to medication, the doctor may recommend a cleansing diet along with treatment to help flush out the tapeworms. Hydration is also important. Any segments that pass after treatment should be collected and disposed of to prevent spread.

Medications like praziquantel are very effective at treating tapeworm infections in humans. When taken as directed under medical supervision, the infection can be eliminated quickly with generally mild side effects.


There are several ways to help prevent tapeworm transmission between cats and humans:

  • Regularly deworm cats for tapeworms. Many vets recommend deworming kittens starting at 2 weeks old and then every 2 weeks until 3 months old. Adult cats should be dewormed 1-4 times per year based on risk factors. Anthelmintic drugs like praziquantel are effective at killing tapeworms in cats. Some flea control products also contain praziquantel to treat tapeworms (1).
  • Control fleas on pets and in the home. Fleas ingest tapeworm eggs when feeding on rodents and spread them to cats. Vigilant flea control breaks this life cycle. Vacuuming and washing pet bedding regularly also helps remove flea eggs and developing larvae (2).
  • Practice good hygiene and handwashing. Thorough handwashing after gardening, cleaning the litter box, or other exposure to potential tapeworm eggs can prevent human ingestion and infection (3).

By keeping cats flea-free and dewormed, the risk of tapeworm infection passing between pets and humans is greatly reduced.

Risk Factors

Certain groups are at higher risk of infection from cat tapeworms than others. Children and immunocompromised individuals are particularly susceptible to tapeworm infections from cats.

Children are at increased risk for a few reasons. Their hygiene habits like handwashing may not be as thorough as adults, so there is a greater chance of accidentally ingesting tapeworm eggs if exposed. Children also spend more time playing on floors and grass where tapeworm segments may have been deposited. Additionally, children are more likely to put contaminated fingers or objects in their mouths compared to adults.

Those with weakened immune systems, such as people with HIV/AIDS, cancer patients undergoing chemotherapy, and organ transplant recipients taking immunosuppressant medications are also vulnerable. Their diminished immune function makes it harder for their bodies to detect and destroy tapeworm larvae before they migrate and develop into adult worms.

To reduce infection risks, parents should monitor young children closely and promote thorough handwashing. Immunocompromised individuals should take extra care around cats and avoid exposure to any potentially contaminated surfaces or soil. Controlling flea infestations on cats is also an important preventative measure for these higher risk groups.


In summary, while tapeworms in cats are quite common, transmission to humans is rare. The most common tapeworm species found in cats that can infect humans is Dipylidium caninum. This infection occurs when humans ingest infected fleas, either through poor hygiene or exposure to flea-infested areas. The infection generally causes mild symptoms like abdominal discomfort, nausea, diarrhea, and weight loss. Cases are easily treated with medication that kills the tapeworms. To prevent transmission, proper flea control on cats is essential, along with good hygiene practices like washing hands before meals. While tapeworms from cats can technically spread to humans, infections are uncommon and easily managed. With proper precautions, cat owners can rest assured knowing their furry companions pose minimal risks related to these parasites.

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