cat sitting in covered litter box

How Do Cats Get Worms?


This article is written by Pet Circle veterinarian, Dr Brittany Ward BVSc

If you're a cat owner, chances are you've wondered how susceptible your cat or kitten is to worms. Whether your cat loves to roam the great outdoors or prefers the cozy corners of your home, the threat of worm infection is real and can pose a variety of health issues.

The consequences range from mild digestive disturbances to severe complications like anaemia, vomiting, and even sudden death in extreme cases. With various types of worms such as roundworms, tapeworms, and hookworms, it's essential to understand the different ways your cat could get infected to effectively safeguard their health.

In this article we demystify the subject by exploring the common ways cats get worms so you'll be better equipped to protect your cat from uncomfortable and potentially dangerous worm infestations.


  1. Types Of Common Intestinal Worms
  2. How Do Cats Get Roundworms?
  3. How Do Cats Get Hookworms?
  4. How Do Cats Get Tapeworms?
  5. What Are The Common Sources of Infection?
  6. Signs of Worm Infection
  7. Prevention and Treatment of Worms
  8. Frequently Asked Questions
  9. Types Of Common Intestinal Worms

    There are three main types of intestinal worms that affect cats:
    • Roundworms
    • Hookworms
    • Tapeworms

    How Do Cats Get Roundworms?

    roundworm under microscope

    Roundworms can use a few different routes to infect your cat:
    • Ingesting worms eggs from the faeces of an infected cat or environment
    • Ingesting a prey animal, suggest as rodents, that have ingested the eggs
    • Nursing from an infected queen (mother cat) - particularly in kittens

    How Do Cats Get Hookworms?

    There are multiple ways that hookworms can infect cats:
    • Consuming larvae from the faeces of an infected cat
    • Consuming a prey animal containing infective larvae in their tissues
    • Via larval penetration of the cat's skin
    • Nursing from an infected mother cat (typically in kittens)

    How Do Cats Get Tapeworms?

    There are three different tapeworms that can affect cats; Flea Tapeworm, the Cat Tapeworm and the Zipper Worm. The method of infection is dependent on the species of tapeworm involved.

    Tapeworms use an intermediate host as part of their life cycle. In order to become infected with tapeworms, your cat must consume the intermediate host.

    What Intermediate Hosts Could Your Cat Consume?
    Flea Tapeworm - As its name suggests, the Flea Tapeworm uses the flea as its intermediate host. Cats can become infected by eating infected adult fleas. This usually occurs during grooming.
    Cat Tapeworm - Taenia Taeniaeformis relies on rodents and small mammals as the intermediate host, meaning cats can become infected by eating contaminated rats, mice or hares.
    Zipper Worm - Cats can become infected with the Zipper Worm via the two intermediate hosts. They may accidentally eat the first intermediate host, Copepods, while drinking contaminated water and become infected with larval cysts. Or, they could become infected with adult worms after eating raw meat from the second intermediate host, small reptiles, frogs, birds or mammals.

    What Are The Common Sources of Infection?

    dog and cat snuggling on grass

    You may be wondering, how can cats get worms if they don't eat faeces? This is where vectors come into play. A vector is anything that can transmit a pathogen, including parasites. A vector most commonly refers to an organism, such as ticks or mosquitoes. Inanimate objects that may assist in transmission can be called passive vectors or fomites. The most common source of parasite infection for cats is vectors.

    So what are the common vectors and how do you avoid them?

    Via Faeces

    Worm eggs are shed in faeces, and faeces are the primary source of the worm larvae that can infect our pets, however, your cat doesn't need to be eating faeces directly to become infected. Faeces can contaminate many common sources of infection.

    The most common method of faecal based infection is by drinking contaminated water or grooming their coat which could contain faeces or contaminated soil. Eating grass that has been contaminated with faecal matter, could also be another potential source of infection.

    Provide fresh water, such as from a water fountain, that is separated from toileting areas and you can offer clean, potted cat grass as a safer alternative.

    Via Soil

    Soil is easily contaminated by faeces and can spread worms to your cat. Contaminated soil can cling to your cat's fur where it is picked up during grooming and may be consumed while eating off the ground or chewing on grass. Hookworm larvae in the soil can also penetrate through your cats skin, commonly on the feet, and migrate through their tissues. These eggs and larvae can survive in the soil for weeks and sometimes even years.

    Via Fleas

    Fleas are an essential vector for the Flea Tapeworm. Cats become infected after eating fleas containing larval cysts. The most common method of flea ingestion in cats is during grooming. A flea infection can amplify this risk by making your cat itchy and more likely to groom or bite at themselves. Fleas can also persist in the environment or survive on other animals, meaning ongoing prevention is a key method of controlling the Flea Tapeworm.

    Via Hunting and Diet

    A common vector for parasites, particularly those affecting cats, is prey animals, such as rodents, hares, birds and reptiles. Not only do some species of tapeworm rely on these species for their life cycle, but larval roundworms or hookworms may also be present in these species. This means cats that like to hunt these small prey, most commonly outdoor cats, are at an increased risk of intestinal worm infection. However, if your indoor-only cat finds and hunts mice or lizards inside the home, they are also at an increased risk.

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    Via Mother's Milk

    Kitten worming should be started from 2 weeks of age. The reason for this is because their mother's milk is a potential source of roundworm and hookworm infection. Larval stages of roundworms and hookworms may migrate through the body and form cysts in the tissues. They become reactivated during pregnancy and migrate to the mammary tissue, infecting kittens as they drink. Maintaining regular worming prevention during pregnancy is important for protecting kittens.

    Via Cross-Species Transmission

    Multi-cat households have an increased risk of worm infections, especially if one of the cats has outdoor access as they can spread the worms to other cats. What about multi-pet households though?

    Other animals in the house can be a source of intestinal worms for your cat. Dogs particularly, share many common intestinal worms with cats and can also be a source of fleas. Dogs, who often have access to the outdoors, can pick up fleas, bring contaminated soil into the house, carry infected faeces on their coat/paws or may be harbouring a silent worm infection. To ensure complete control of worms, all pets in the household should be on regular prevention.

    Signs Of Worm Infection

    Common Symptoms of Intestinal Worms:
    • Diarrhoea (Sometimes with Blood)
    • Worms or Worm segments in stools or around anus
    • Vomiting
    • Weight loss
    • Distended "Pot Belly" abdomen
    • Weakness
    • Illthrift
    • Unkempt, dull coat
    • Anaemia
    • No signs at all - many cats will not show signs of infection

    Prevention and Treatment of Worms

    image of nexgard spectra for cats packages

    Did you know that Nexgard Spectra for Cats covers all of the parasites of concern in Australia? This monthly spot-on provides protection against fleas, ticks, mites, heartworm, lungworm, intestinal worms and tapeworms.

    The treatment of worms in cats requires the use of a dewormer. The active ingredients used in our preventative medications are dewormers and predominantly work by killing any worms or larvae that your cat has picked up since their last treatment. For this reason, regular use of a worming treatment is recommended to prevent your cat harbouring a worm infestation.

    Tapeworms are the exception to the rule. Tapeworm treatment, particularly the Zipperworm, requires a higher dose of the effective active ingredient (Praziquantel) than is contained in preventatives. Pets with large worm burdens may also require higher worming doses or more frequent doses. Sometimes these may be administered via injection.

    If you notice worms in your cat's vomit or faeces, it is recommended to collect the worm and take it to your vet for identification. A sample of the faeces will also be helpful as worm eggs are passed in the faeces and can be identified by a faecal float test.

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    Frequently Asked Questions

    Can Indoor Cats Get Worms?

    All cats are at risk of intestinal worms, including indoor-only cats. While their risk is reduced, indoor-only cats can be exposed to contaminated soil that we humans might bring into the house on clothing and shoes. Small prey can access our homes, exposing indoor-only cats to worms and our dogs can also bring in fleas or worm eggs/larvae. If an indoor-only and outdoor cat live in the same house then the outdoor cat becomes a source of infection.

    Are Some Cats More Susceptible to Worms Than Others?

    Cats with outdoor access are more likely to be exposed to infected faeces or vectors, particularly contaminated environments as they are exploring. Even if your cat doesn't leave your yard, strays, neighbourhood cats or other animals can access the area and contribute to contamination.

    Small prey animals are a potential source of infection for all intestinal worms. This means cats prone to hunting these small types of prey, including rodents, hares, birds, earthworms, cockroaches and reptiles, are at an increased risk of getting worms.

    Similarly, cats on a raw food diet have a higher chance of exposure to worm larvae and cysts in the meat.

    Younger and older animals have weakened immune systems, which can make them susceptible to pathogens, including to intestinal worms. These cats are more likely to experience severe illness following worm infections. Kittens also have additional routes of exposure through their mothers milk and can quickly outgrow their worming dose, leaving them vulnerable to infection.

    Can Humans Get Worms From Cats?

    Yes. Humans can get worms from cats. Tapeworms in particular can cause severe illness in humans if they form larval cysts in tissues throughout the body, including nervous system tissue, the brain, liver and lungs. Adult tapeworms may also develop if a flea is accidentally ingested or from eating raw meat.

    Roundworms can infect people when the eggs are ingested, often from a contaminated environment. Hookworms are more likely to affect people when larvae penetrate the skin and migrate through the tissues under the skin.

    Children are at the greatest risk for getting worms from cats as they are more likely to eat contaminated soil or walk around barefoot.

    Can Cats Get Worms From Mice?

    Yes. Mice and rats can potential be a source of roundworms, hookworms and tapeworms if they are consumed by cats. Rodents may consume roundworm eggs in faeces, becoming a source of contamination for cats. Hookworm larvae may migrate through their tissues or get into their tissues following ingestion, and then infect your cat. They can also harbour Tapeworm larvae, which may be then ingested by cats, the definitive host.

    Can Cats Get Worms From Raw Meat?

    Other species of mammals can also harbour worm larvae, including chickens, sheep, cattle, goats and even kangaroos. Tapeworms particularly form cysts inside the tissues of these animals, which can then be consumed by cats to develop into adult worms. Outdoor cats, particularly those in rural areas, may have access to the offal or carcasses of these infected species. The most common source, however, is a raw meat diet. Cats on a raw food diet are at an increased risk of intestinal worms, especially tapeworms. The larvae found in the raw meat can be inactivated by cooking the meat.

    Can Cats Get Worms From Eating Flies?

    The flies themselves will not be affected by worms or carry larvae in their bodies. However, flies often come into contact with faeces. A fly that has come into contact with faeces from a shedding cat may pick up eggs on their body and transport them. If that fly is then consumed while carrying infective eggs, they may become a source of worm infection.

    Further Reading

    Want to read more? Check out our other articles:

    Ringworm in Cats

    Can Indoor Cats Get Fleas?

    Can You Flush Cat Litter?

    Causes of Diarrhoea in Cats

    What is the Best Flea and Tick Treatment For Cats?

    Your Cat's Digestive System Explained

    How To Pill A Cat

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