How to Prevent and Treat Worms in Dogs: The Vet’s Guide

dogs with worms

One of the issues that vets frequently have to remind their clients about is the need to ensure their pet dogs are regularly wormed using an effective worming product at the correct dosage. Despite this, some dog owners are still unaware of the potential threat posed by intestinal worms to the health not only of their pet but also to human health.

What are intestinal worms?

These are parasites which live in the gut of an infested animal. The most common ones, and the ones which are most likely to be seen in the UK, are tapeworms, roundworms, hookworms and whipworms.

Of these only two of them are able to be seen with the naked eye – tapeworms and roundworms. Despite the name, roundworms are actually not round but are long and thin in appearance.

How do dogs get worms?

Dogs can become infected in differing ways depending on the type of worm and depending on the habits of the dog. By far the most common cause of worm infestation is through fleas; when a dog grooms himself as a means of relieving the itching and irritation that fleas can cause he can easily ingest the fleas. The type of worm which is most commonly passed on through fleas is the tapeworm. Check your dogs’ fur and skin regularly for the telltale gritty black droppings that indicate a flea infestation and treat them immediately.

If your dog is a scavenger he can easily pick up the eggs of roundworms, hookworms and whipworms from contaminated soil, either directly or by for example playing with a toy or eating food that has been left on a piece of ground where faeces have been deposited either by the dog itself or by other animals. This is one of the reasons why it is so important to clear up your dog’s mess straight away rather than leave it on the ground where it can pose a health hazard to animals and humans alike.

How to use a snuffle mat by Ruffle ...
How to use a snuffle mat by Ruffle Snuffle

Another way your dog can pick up the eggs of roundworms, hookworms, tapeworms and whipworms is by eating the carcasses of dead mice, birds or rabbits which are infected with worm larvae. This is possible because some worm eggs can lay dormant for a period of months or years.

Puppies are generally born already infected with roundworms and sometimes hookworms through their mother either through the placenta or her milk. It is absolutely vital that you follow your vet’s advice on worming puppies.

Hookworms can occasionally be picked up by a dog simply walking on contaminated soil because this particular parasite can infiltrate the dog’s feet.

How do I know my dog has worms?

It is not often that you can tell your dog has worms simply by looking however there are exceptions. A severe roundworm infestation can result in entire worms being excreted in the faeces or vomit. Tapeworm segments look like grains of rice and you can sometimes see these in the dog’s excrement or around the anus. In many cases there are very few other symptoms but some to look for include:

  • Diarrhoea and vomiting
  • Lethargy
  • Loss of condition of the coat
  • Loss of appetite and/or dehydration
  • Swollen abdomen or ‘pot belly’ especially in young puppies
  • Coughing or retching
  • ‘Scooting’ along the ground
  • Excessive cleaning and nibbling around the area of the bottom

In very severe cases there could be pneumonia or a blocked intestine. Puppies are always prone to worm infestations but older dogs or those with underlying health issues can also be vulnerable to more severe consequences.

Are people at risk from worms?

Aside from the sheer unpleasantness of a worm infestation there is a risk to human health. Children, pregnant women and elderly people in particular are at risk from Toxocariasis, an infection passed on through roundworm eggs which can be contracted from contaminated food or soil, from touching an infected dog’s coat or from clearing up contaminated faeces and failing to thoroughly wash hands. Some studies have indicated that public gardens, parks and play areas show the presence of worm eggs in the soil.

Very rarely, tapeworm eggs could be present in contaminated meat but this is very rare in the UK.

It is possible but very rare for humans to catch hookworms or whipworms from dogs; similarly tapeworm infestations have been seen in humans but this is unusual and to catch it from a dog you would have to inadvertently ingest an infected flea.

In most cases symptoms of a worm infection in humans will be negligible but occasionally there could be a fever, headaches, stomach cramps or a cough. In very cases there could be more severe symptoms as the infection begins to affect the liver, lungs, eyes or brain.

Types of intestinal worms in dogs

Toxocara Canis, or roundworm, is by far the most common type of worm which affects domestic dogs. These white, spaghetti-like organisms can measure up to 15cm in length and bunch tightly together in the digestive system and when they are excreted. Their direct life cycle means that they have no need of a secondary or intermediate host but rather can transfer from environment to animal, or from animal to animal. 

The three types of roundworm are ascarids, hookworms and whipworms.

Within the genus, the only types of worm which are not zoonotic, i.e. that does not transfer from animal to human, is the whipworm (Trichuris vulpis) and one of the ascarids (Toxocaris leonine, the dog and cat roundworm).

Tapeworms are more flat and segmented in appearance and these do need an intermediate host to complete their life cycle. The flea tapeworm and the dog/fox tapeworm (incubated by ruminants, rodents and pigs) are both zoonotic. 

The importance of de-worming your dog

It cannot be stressed highly enough that the way to avoid worm infestation in your dog and subsequently any risk to people is to make sure you administer a wormer on a regular basis and de-worm immediately when necessary. Most dogs will come into contact with fleas and worms at some point in their lives and this is nothing to be ashamed of but it does have to be dealt with promptly.

De-worming products are very efficient at killing worms however they are not a long-term solution and dogs can easily become re-infected particularly if they are allowed to frequent contaminated sites or if their faeces are not cleaned away properly. Quarterly worming treatments are recommended by vets but if your dog is one that regularly comes into contact with wildlife, birds or cats then a more frequent worming treatment programme will be necessary. Other instances where a more frequent treatment is advisable include:

  • Where there are children, pregnant women or elderly people a dog should be wormed monthly
  • Weaned puppies should be wormed monthly up to 6 months of age
  • Where a dog has a heavy flea infestation he should be wormed and treated specifically for tapeworm.

Your vet will assess a variety of factors in order to formulate the correct worming treatment for your dog. He/she will look at the age and health of the dog, the living arrangements of the dog – whether he lives out or in, whether the dog is a hunter or scavenger, whether there are other animals in the home and whether there are children or pregnant women in the home.

If you take your dog abroad be aware that it is compulsory to have him treated for tapeworm before returning to the UK. This is because of a risk to human health from some Echinococcus tapeworms not found in the UK.

Treatments for worms

There are a number of ways you can administer a de-worming treatment to your dog at home. These include tablets, pastes, granules, suspensions and liquid solutions so however fussy your dog is about taking medicines there is always at least one method that is suitable. One of the most popular worming treatments is Veloxa, made by Frontline and in a palatable beef flavour, which kills all of the most common intestinal worms.  Below is a list of the active ingredients and associated spectrum in worming treatments.

Praziquantel  for Tapeworm Dipylidium/Taenia/Echinococcus

Febantel + pyrantel  for Roundworm Ascarid/Hookworm/Whipworm

Febendazole  for Roundworm as above

Nitroscanate  for Roundworm Ascarid/Hookworm + Tapeworm Dipylidium/Taenia and limited use for Tapeworm Echinococcus

Piperazine citrate for Roundworm Ascarid only

How to stay safe

There are a few simple precautions that vets advise dog owners to take in order to minimise the risk of worm infestations within the family and these are:

  • Always wash hands thoroughly after handling pets or their faeces
  • Always wear gloves to clear up faeces and clear up immediately
  • De-worm your dog regularly using the correct wormer and dosage
  • Teach children the importance of hygiene around animals
  • Wash all fruit and vegetables before eating
  • Wear gloves when gardening
  • Cover children’s sandpits and play areas when not in use
  • Avoid giving unprocessed, raw meat to your dog.

This subject may be a focus point you don’t want to learn about, but the importance of the subject is vital for both yourself and your pets health.