Welcoming a new kitten into the family is an exciting time. But you may be surprised to know that your kitten doesn’t need to have ever set a paw outside to be bringing along worms with them.

Roundworm – Toxocara cati 

The roundworm Toxocara cati is extremely common in kittens. The adult worms live in the cat’s gut and lay microscopic eggs which are passed in the cat’s stool. The eggs can survive a long time in the environment, for example in soil. Consequently, other cats become infected by inadvertently eating these eggs.

Once ingested, the eggs hatch into baby worms (called larvae), which burrow their way out of the stomach and migrate around the body, eventually ending up in the gut. Here the larvae grow into adult worms, lay their own eggs, and so the life cycle continues. In a pregnant cat, the larvae migrate to the mammary glands and make their way into her milk. This ensures they are passed on to her kittens when they feed.

Toxocara cati eggs are only able to mature into adult worms inside cats. The eggs can be ingested by other animals, such as mice. Instead of ending up as adults in the gut, the larvae set up home in other organs as they migrate around the body. If the animal is eventually eaten by a cat, the larvae can then continue developing and turn into adults.

How do I know if my kitten has roundworm?

As Toxocara cati is passed onto kittens through Mum’s milk, we can presume that all kittens come ready infected. Symptoms of infection may include poor appetite, a pot belly, gastrointestinal upset (including vomiting up large numbers of adult worms – which can be 10 cm long!), and stunted growth. Some kittens may not show obvious symptoms, but this doesn’t mean that they’re not infected.

Does Toxocara pose any risk to me and my family?

Toxocara cati can also infect people, causing much more serious symptoms than those seen in cats. The larvae aren’t able to grow into adults in humans, but cause damage as they migrate around the body. You may have heard of ocular larval migrans, a serious condition caused by larvae migrating in the eye that can result in permanent blindness. Such conditions are particularly common in young children as they’re much more likely to accidentally ingest eggs from the environment – sandpits are often a popular cat latrine – and they tend to put their fingers and other objects in their mouths. Green-fingered adults are also at an increased risk of infection via ingestion of infected soil under their fingernails. 

How do I reduce the risk to my family and my kitten?

The good news is that kittens can easily be treated for Toxocara cati. There are a wide range of products available, and your vet can help you to choose what’s best for your pet. You may find a tablet easiest to administer. Alternatively, you may prefer a liquid spot on treatment to apply to the skin. Your vet or veterinary nurse will be able to show you how to administer the treatment, or even do it for you. It’s recommended that kittens are treated for Toxocara cati every two weeks until they’re three months old, then monthly until six months. This is to ensure each new lifecycle of the parasite is killed as the adults emerge. 

Eggs passed in your kitten or cat’s stool aren’t a danger straight away. It takes at least two weeks of incubation in the environment for eggs to become infective. This means that regularly cleaning the litter tray, so eggs don’t get the chance to become infective, is an important step in breaking the lifecycle. General hygiene measures such as washing hands after handling the kitten are also important, as eggs from the stool can become attached to the fur. Ensure fruit and vegetables are washed before eating as they can become contaminated whilst growing. Encourage children to wash their hands after playing outdoors, especially before eating.

Tapeworm – Dipylidium caninum

Another common parasite of kittens is the tapeworm Dipylidium caninum (despite the name, it infects felines as well as canines). The larvae of this tapeworm can live inside fleas. Cats often ingest fleas whilst grooming. This is the reason you don’t necessarily see adult fleas on an infested cat, but allows the tapeworm to set up infection inside them. Although Dipylidium caninum may not cause your kitten serious health problems, these worms certainly have the gross factor!

The adults can grow half a metre long inside the gut and their offspring, passed from the anus, are visible to the naked eye (about the size of a grain of rice) and can move! Flea infestation is common in kittens. So if your kitten has fleas, they will need to be treated for tapeworm as well as roundworm. Plus treatment to get rid of the fleas!

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It is important to note that dog flea treatments should never be used on cats. Some contain an ingredient called permethrin which is extremely toxic to cats; your veterinary practice can help you select a treatment that’s feline-friendly. 

Worm control in older cats

Once your kitten is six months of age, you and your vet can work together to come up with a parasite prevention protocol that fits your cat’s lifestyle. Prolific mousers may need to be treated more frequently than indoor adults. They’re at an increased risk of ingesting prey infected with Toxocara. There are many prescription medications available that treat multiple parasites all in one go. For example, fleas, ticks and roundworm, reducing the need for multiple products. 

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