What are the most common worms in cats?
The most common types of intestinal worms found in cats are roundworms, tapeworms, and hookworms:
Roundworms are perhaps the most widespread intestinal parasite in cats, with 25% to 75% of cats infected according to Cornell University’s College of Veterinary Medicine (https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/gastrointestinal-parasites-cats). The main species are Toxocara cati and Toxascaris leonina. Roundworms live in the small intestine and can cause a pot-bellied appearance in kittens.
Tapeworms like Dipylidium caninum attach themselves to the intestinal wall and shed segments that are passed in the feces and look like rice grains. Tapeworms are transmitted when a cat ingests an infected flea.
Hookworms such as Ancylostoma tubaeforme bite into the intestinal wall and suck blood and can cause iron deficiency anemia. Cats get infected by ingesting larvae from contaminated soil.
Heartworms like Dirofilaria immitis are transmitted through the bite of infected mosquitoes. They migrate to the heart and pulmonary arteries where they mature into worms up to 12 inches long, potentially causing severe heart and lung disease.
How do cats get infected with worms?
Cats can become infected with intestinal worms, like roundworms and hookworms, by ingesting worm eggs or larvae from the environment, prey, or their mother’s milk. These worm eggs and larvae are microscopic, so they can be easily ingested by cats as they groom themselves and explore their surroundings with their mouth. Roundworm eggs can survive in the soil for years.
Another way cats acquire worm infections is through intermediate hosts like birds, rodents, and fleas. Tapeworm infection happens when a cat ingests an infected flea while grooming. The flea releases the tapeworm larvae into the cat’s digestive system where they develop into adult tapeworms.
Mosquito bites can transmit dog heartworm larvae into a cat’s bloodstream. Once inside the body, the larvae migrate to the heart and pulmonary arteries where they mature into adult heartworms in around 6-7 months. So an infected mosquito bite can lead to heartworm disease in cats.
Kittens can also get infected with roundworms through their mother’s milk if the mother cat has a roundworm infection. So proper deworming of the mother and kittens is important to prevent this roundworm transmission.
What are the symptoms of worm infections in cats?
Some of the most common symptoms of worm infections in cats include:
- Diarrhea – Worms can irritate the gastrointestinal tract and cause diarrhea. Both roundworms and tapeworms can cause diarrhea in cats.
- Vomiting – Roundworms, hookworms, and tapeworms can all lead to vomiting as they irritate the digestive tract.
- Weight loss – Worms rob the cat of nutrients, which can lead to weight loss and malnutrition over time. This is most noticeable with large roundworm infections.
- Dull coat – The coat may become dull and thin due to nutritional deficiencies caused by worms.
- Coughing – Lungworm infections can cause coughing episodes as the worms migrate through and irritate the respiratory tract.
- Fatigue – Heartworm infections can lead to fatigue and lethargy as the heart has to work harder to compensate.
However, some cats may show no obvious symptoms at all, especially in mild infections. The only way to diagnose a worm infection is through a veterinary fecal examination.
How are worm infections diagnosed in cats?
Worm infections in cats are often diagnosed through a fecal examination. Veterinarians will take a stool sample from the cat and examine it under a microscope for parasite eggs. This allows them to identify the type of worm the cat is infected with based on the appearance and size of the eggs.
According to PetMD, a fecal flotation test is commonly used to check for worm eggs. In this test the stool sample is mixed with a solution that causes the eggs to float to the top for easier viewing.
Some types of worms like heartworm are diagnosed through a blood test rather than a fecal exam. The blood is checked for antigens or proteins from the adult heartworms. This allows veterinarians to detect whether heartworm larvae are present and determine the level of infection.
In addition to lab tests, your veterinarian may ask about any symptoms you have observed in your cat. Symptoms like vomiting, diarrhea, weight loss or a dull coat can point to a possible worm infection. Your vet will combine this information with the test results to make a diagnosis.
How are worm infections treated in cats?
The most common treatment for worm infections in cats is deworming medication. There are several effective dewormers available including tablets, chewables, topicals, and injectables. According to the ASPCA, some common deworming medications include:
- Pyrantel pamoate (removes roundworms and hookworms)
- Fenbendazole (removes roundworms, hookworms, and whipworms)
- Praziquantel (removes tapeworms)
- Milbemycin oxime (removes roundworms, hookworms, and whipworms)
- Ivermectin (removes roundworms)
The specific medication, dosage, and duration will depend on the type of worm infection. Kittens and puppies often undergo routine deworming as part of their vaccination schedule.
Treating heartworm infections in cats is more complex than treating intestinal worms. According to the American Heartworm Society, heartworm preventatives are recommended year-round for cats in heartworm endemic areas. Treatment options for an active heartworm infection may include surgical removal of worms, medication, cage rest, and supportive care https://www.heartwormsociety.org/pet-owner-resources/feline-heartworm.
Can humans get worms from cats?
Yes, some types of worms that commonly infect cats can also be transmitted to humans. This is especially a concern for young children who may come into close contact with cats. Some of the most notable worm species that can spread from cats to humans include:
Toxocara cati and Toxocara leonina – These roundworm species can cause toxocariasis in humans, which often leads to vision loss and other serious symptoms. Humans can ingest Toxocara eggs that have been shed in an infected cat’s feces. The CDC estimates 14% of Americans have been infected with Toxocara at some point. [1]
Ancylostoma tubaeforme – This feline hookworm can occasionally cause cutaneous larva migrans or “creeping eruption” in humans who come into contact with infective larvae. This leads to intense itching and serpiginous skin lesions. [2]
Thus, while petting or playing with a cat infected with worms does not guarantee human transmission, there are risks especially for kids with frequent exposure. Practicing good hygiene like washing hands after handling cats can help reduce infection risk.
What is the risk from petting a cat with worms?
The risk of catching worms from simply petting, kissing, or holding an infected cat is actually quite low. Intestinal worms like roundworms and hookworms are mainly transmitted through ingestion of microscopic eggs shed in the feces of infected cats (CDC, 2022). Therefore, there is little risk of transmission just from petting or touching an infected cat’s fur.
However, there may be a greater risk of exposure if a person comes into contact with areas contaminated by an infected cat’s feces. The eggs can sometimes be found on a cat’s rear end, paws, fur, bedding, litter box, toys, food bowls, and other surfaces they have access to. If eggs get transferred to a person’s hands and ingested through poor hygiene, this can potentially lead to infection.
The main ways to avoid exposure are picking up all feces promptly, keeping cats indoors, washing hands after handling cats, and preventing cats from accessing areas where feces may be ingested. But overall, simply petting or holding a cat with worms poses little risk of transmission (YourPetandYou, 2022). The greater concern is accidental ingestion of microscopic worm eggs shed in the feces.
So while intestinal worms in cats are common, the risk of transmission from casual contact like petting is low. Focus should be on controlling infections in cats and preventing exposure to feces. With some basic hygiene and care, worms in cats do not have to pose a significant risk to humans.
How can worm infections be prevented in cats?
There are a few key ways to help prevent worm infections in cats:
Deworming kittens and regular deworming for adult cats is important. Kittens should be dewormed starting at 2-3 weeks of age, then every 2 weeks until 3 months old, then monthly until 6 months old. Adult cats should be dewormed at least 2-4 times per year and preferably year round if they go outdoors and hunt. Common dewormers include pyrantel pamoate, fenbendazole, praziquantel, moxidectin, and ivermectin. Consult your veterinarian for the best deworming schedule and products for your cat. See https://www.ingleside.com/services/cats/blog/cat-deworming-info-you-need-avoid-potentially-fatal-condition and https://www.dailypaws.com/cats-kittens/health-care/feline-parasites/worms-in-cats-what-to-do-and-how-to-avoid-them
Year-round heartworm prevention is also important. Heartworm preventatives for cats contain ingredients that also prevent common intestinal worms like roundworms and hookworms. They should be given per label directions, usually monthly. Some heartworm prevention options include ivermectin, milbemycin oxime, moxidectin, and selamectin. Consult your veterinarian for the best heartworm prevention product for your cat.
What precautions can people take around infected cats?
People can take some simple precautions when around cats infected with worms to reduce the risk of infection:
Proper hygiene is important. Be sure to wash hands thoroughly with soap and water after touching or petting an infected cat. Avoid touching your face or eating before washing up.
Clean the litter box daily, wearing gloves, to remove feces which could contain worm eggs. Properly dispose of the waste and disinfect the box.
Control fleas and mosquitoes in your home and on your cats. Fleas can spread tapeworms and mosquitoes can transmit heartworms to cats. Use monthly topical flea/tick prevention medications prescribed by your veterinarian.
Take infected cats to the veterinarian for diagnosis and prescription deworming medication to kill the worms. Follow their advice on containment and cleaning to prevent reinfection.
Pregnant women should take extra care around infected cats, avoiding litter box duties. The toxoplasmosis parasite can infect humans and pose risks to an unborn baby.1
In general, healthy adults are at low risk of getting worms from infected cats with proper hygiene. But people with weakened immune systems should avoid exposure until the cat has been dewormed.
When to seek veterinary care for worms?
If you suspect your cat has a worm infection, it’s important to seek veterinary care for proper diagnosis and treatment. Some signs that indicate veterinary care is needed include:
Diarrhea and vomiting lasting more than 24 hours – Persistent diarrhea and vomiting can indicate a heavy worm burden that needs medical treatment. Significant diarrhea and vomiting can also lead to dehydration, which is dangerous for cats.
Lethargy, weight loss, poor coat – Worm infections can cause fatigue, weight loss, and a poor, dull haircoat as they rob the cat of nutrition. These signs warrant a vet visit for diagnosis.
Prior to deworming if infection is suspected – It’s best to have your vet confirm the presence of an intestinal worm infection through a fecal test before deworming. This allows them to provide the proper deworming medication and dosage.
Bringing a fresh fecal sample to the vet can allow them to identify any worm eggs under the microscope. Diagnostic testing prior to treatment helps ensure the proper wormer is used and the full course is given to fully eliminate the worms.