Gut Worms in Dogs - a Problem for Pets, and People

Posted by MyDogDoc on

Gut worms are a common problem in dogs, and can be spread to humans. So we recommend treating your dog regularly.

  • There are two main types of worms that affect dogs in the UK: roundworms and tapeworms

  • They both live in your dog’s guts (intestines)

  • you may not even know that your adult dog has them, but…….

…...roundworms can cause severe illness in puppies - and children

  • They spread in soil, poo, and in the case of tapeworms by fleas

  • Your vet can help you with a worm prevention plan.

What gut worms do dogs get?

There are two main types of worms that affect dogs in the UK:


Roundworms look like spaghetti and can grow up to 15cm long! They live in dogs’ - or other animals’ - guts (intestines). Here they take food from, and cause damage to, the gut. They produce tiny eggs which are passed in the poo and eaten by another animal (or human). The eggs are sticky, so can be spread by sticking to things like dog fur or even flies’ feet! Roundworm eggs are long-lived and can survive disinfection.

Roundworms can be very serious for puppies, as they can make them dehydrated, cause anaemia (lack of red blood cells), and in large numbers even cause a blockage in the guts.

Roundworms are spread…

  • directly by an animal eating the eggs. Humans can become infected this way - for example, flies landing on dog poo then on human food.

  • indirectly by a second animal, often a rat, eating the eggs. These hatch into baby worms (larvae) and move within the rat, making the rat ill. If a dog eats the rat, it can become infected.

  • From bitch to puppies by the worm larvae moving from the guts of a pregnant bitch to her womb and infecting her puppies, or to her breast tissue when she is feeding her pups and being passed to the pups in the milk.

  • Most human infections are picked up from gardens where a bitch and puppies, or foxes, have been.


Tapeworms affect dogs and other animals. They attach to the lining of the intestine. The worms are made from small segments that detach and pass in the dog’s poo. The segments look a bit like grains of rice, and can sometimes be seen crawling around your dog’s bottom! Each segment contains tapeworm eggs, which, if eaten by another animal, form a cyst inside that animal’s body. This can affect farm animals, like sheep, if they eat grass where dog poo has been. When a dog eats raw meat or offal (liver, kidneys, lungs) that includes the cyst and eggs, a new tapeworm grows inside the dog.

One common type of tapeworm in the UK is spread by fleas. Fleas eat eggs from dog poo and, while grooming, dogs eat the infected fleas.

Whip worms and thread worms

There are also whip worms and thread worms that can affect dogs, but they are rare in the UK. They are a concern if your dog travels with you to the EU however.

What are the symptoms of gut worms in dogs?

Dogs (and humans) can have worms in their gut without obvious symptoms, but if left untreated they cause illness. This is especially the case in puppies.

In dogs, signs include:

  • Dull coat

  • Itchy bottom (tapeworm)

  • Diarrhoea

  • Tiredness

  • Weight Loss

  • Puppies may also become bloated, and in really heavy infections worms can even cause a blockage in their intestines.

What are the risks to humans?

Although gut worm infections in humans are rare, there is a greater risk to children playing outside around dog poo.

The larvae of both round and tapeworms can move out of the gut in humans. This is called larval migration.

Tapeworm larvaec an form cysts in human organs, such as the liver, lungs, and even brain - ew! Of course this can stop that organ working properly and cause serious illness.

Roundworm larvae can move through organs, including the eyes, causing severe illness and, in some cases, blindness.

Some tapeworms can grow large and, in rare cases, cause a blockage in the intestines.

How can we try to prevent round worm and tapeworm infections?

Good hygiene:

  • Pick up your dog’s poo!

  • Try to keep your children’s play areas seperate from where your dog poos

  • Wash you hands - after playing with your dog, cleaning up after them, and before you eat

  • Treat your dog regularly with a wormer

  • You can get worming treatments from your vet, from a Suitably Qualified Person (SQP) and over the counter.

  • Some wormers require a prescription and your vet will need to have examined your dog in the last 12 months

  • The best wormer for your dog will depend on your lifestyle, how old your dog is, and what worms they are at risk of getting

If you are unsure which wormer your dog needs and how often to use it, the vets at MyDogDoc would be more than happy to help!

Dog Fleas Gastrointestinal disease Gut Health Intestines Prescription Preventative Care Round Worm Tapeworm Wormers Worms in Poo

← Older Post Newer Post →

MyDogDoc Online Dog Care Advice

First Aid – General Advice

Lets Chat Cushing’s Disease

Looking for more expert advice?

Why not download to MyDogDoc app for more expert content and to speak to our professional vet staff

Download the free app now:

App Store | Google Play

Custom HTML

Add your custom HTML here.