Worms In Cats: Types, Treatment, and Prevention Tips
Wed, April 21, 2021

Worms In Cats: Types, Treatment, and Prevention Tips


Cats infected with worms do not show signs of infection, but they can cause your cat to vomit and lose weight. This was explained by International Cat Care, a resource on feline health. Your cat can suffer from diarrhea and even fail to thrive due to worms. Irritation around the anus can also occur.

“It’s more unusual to have a cat not exposed to them,” said Dr. Cathy Lund of City Kitty, as quoted by Pet MD, a vet authored and approved website. Alarmingly, some worms can even infect humans, causing serious human disease on rare occasions. Fortunately, it’s possible to get rid of worms without panicking.

Fecal Survey of Parasites In Free-Roaming Cats (2018)

Yoko Nagamori and colleagues of Science Direct, a medical and scientific journal portal, collected about 1 g to 5 g of feces from 846 free-roaming cats either from cage traps (when available), or rectally using disposable fecal loops in Northeastern Oklahoma. The samples were examined by centrifugal fecal flotation tests with 33% zinc sulfate solution.

Nagamori and colleagues found that 541 or 63.9% of samples contained at least one parasite and 211 (24.9%) samples contained multiple parasites. Toxocara cati was the most prevalent parasite detected by the researchers (44.6%; 277/846). 13.4% or 113 of 846 cats had Alaria, making it the second most prevalent parasite. 

This was followed by Ancylostoma (11.2%; 95/846), Cystoisospora (9.7%; 82/846), taeniids (7.7%; 65/846), Dipylidium caninum (4.5%; 38/846), Physaloptera (2.2%; 19/846), Eucoleus aerophilus (1.4%; 12/846), Giardia (1.2%; 10/846), and a small (10–12 μm) Toxoplasma-like oocyst (0.1%; 1/846). A few ectoparasite species like Demodex gatoi (0.5%; 4/846) and Cheyletiella (0.1%; 1/846), were also detected.

417 of 846 (49.3%) cats were male and 429 (63.4%) were female. 269 male cats (64.5%) and 272 females cats (63.4%) were positive for at least one parasite. In both males and females, the most commonly detected parasites were T. cati, Alaria, Ancylostoma, Cystoisospora, taeniids, D. caninum, and Physaloptera.

Age was also determined and recorded, with 161 cats (19%) aged 3-5 months, 297 cats (35.1%) aged 6-12 months, and 388 cats (45.9%) aged over 12 months. In the 3-5-month old group, 122 cats (75.8%) were infected by at least one parasite. 186 cats (62.6%) in the 6–12mo and 233 cats (60.1%) in the 12mo and above groups were infected by at least one parasite.

The most prevalent parasites were T. cati (63.4% prevalence in cats 3-5 months versus 40.1% in 6-12 months versus 40.7% >12 months), Alaria (19.9% versus 16.2% versus 9%), Cystoisospora (18% versus 9.1% versus 6.7%), Ancylostoma (9.9% versus 13.1% versus 10.3%), taeniids (5% versus 7.1% versus 9.5%), and D. caninum (4.3% versus 3.7% versus 5.2%).

Nagamori and colleagues concluded that parasite infections are more prevalent in free-roaming felines than in owned cats. Infections were more prevalent in cats between three and five months of age. T. cati and Alaria were the most commonly detected parasites, which can cause zoonotic diseases. Yearly monitoring and application of broad-spectrum endoparasite and ectoparasite control should be done for owned cats that often share the same territories as their free-roaming counterparts.

What Are the Most Common Worms That Infect Cats?

1.     Roundworms

As a common intestinal parasite, intestinal roundworms can be present in cats of all ages across the globe. The most common ones are T. cati and Toxascaris leonine. Eggs from roundworms are passed through the droppings and can survive in the environment for several years. 

Your cat may get infected if it ingests eggs directly from a contaminated environment. Another animal may eat the eggs— which acts as “intermediate hosts”— passing on the infection to your cat if it preys and eats the animal.

2.     Hookworms

Your cat may be infected by ingesting eggs from the environment, from consuming an infected intermediate host, or by the larvae in the environment burrowing through its skin. The most common hookworms in cats are Ancylostoma tubaeforme, and Uncinaria stenocephala, though other species occur in other countries.

3.    Tapeworms

Tapeworms require an intermediate host to eat the eggs from the environment and your cat will be infected if it eats the intermediate host. This is how tapeworms complete their life cycle. The most common tapeworms around the world are Dipylidium caninum and Taenia taeniaeformis.

Immature fleas ingest the eggs of the Dipylidium caninum and it is passed on to your pet when it swallows an infected flea during grooming. On the other hand, Taenia taeniaeformis is transmitted when your cat eats small rodents that have consumed the worm’s eggs from the environment.

How Are Worms Treated and Diagnosed?

A physical exam or an examination of a stool sample under a microscope can aid in the diagnosis of worms. Sending a stool sample to a lab for complete testing might also be done by your veterinarian. Blood tests might be performed to get a complete picture of your cat’s health.

If worms are detected, medications can be prescribed and administered orally at intervals. This depends on the type of worm, degree of infestation, and results of follow-up fecal examinations. Your pet will perform another fecal exam to ensure that the worms have been eliminated.

Be warned that re-infestation is not uncommon, especially if you live in a multi-cat household or own cats that go outside, said Dr. Bruce Kornreich, associate director of the Feline Health Center at the Cornell University College of Veterinary Medicine.

How Can I Prevent My Cat From Being Infected?

Kittens are more susceptible to intestinal infection since their immune systems are not as developed. “Because [kittens] are growing, they can’t afford to lose nutrition or the electrolytes to diarrhea,” he said. What do pet parents like you need to do? “The biggest thing is to be proactive, getting a fecal exam and physical exam and being fastidious with the litter box. Clean and change it frequently,” Kornreich emphasized. It is strongly recommended to adhere to a year-round regiment of flea prevention, either through oral does, topical applications or collars. 

Try to keep your cats indoors, where they cannot prey or eat infected rodents or small animals. Since some worms can migrate to your skin or eyes, “Clean up feces quickly, wash your hands and wear gloves when cleaning the litter box,” Kornreich recommended. Use gloves when gardening as outdoor cats tend to leave their droppings in your garden.

Exercise caution when handling infected cats and litter boxes, as some species of worms can migrate to the human body. Be sure to have your cat diagnosed and treated with worms as soon as possible. Avoid using home remedies to treat worms and only administer medications prescribed by your veterinarian.