How it works

You can read or listen to our modules. There is a play button in each heading so you can listen while you read. Or you can listen to the whole module in one go or download it as a podcast. You'll find a play and download button for the whole module at the bottom of this page. At the end of the module you there is a quiz. You will have to hit the play button on the quiz video and enter your name and email address before you start.

At the end of the module you will:

  • know the key parasites against which dogs in the UK need protection
  • understand why parasite protection needs to be tailored to the specific animal
  • know what questions to ask the dog's owner to ensure the dog gets appropriate parasite cover


Several types of parasite can affect dogs in the UK. The main aims of a parasite control programme and use of parasiticide drugs (flea and tick, and worming products) are to control the parasites that can be transmitted to humans and those that cause or transmit significant disease in dogs. In the UK, these are:

  • fleas
  • roundworm (Toxocara canis)
  • ticks
  • tapeworm  
  • lungworm (Angiostrongylus vasorum

While practical measures (like picking up poo and washing hands) are highly important in controlling diseases caused by parasites, the use of parasiticide medicines also plays an important role in controlling these parasites. The level or type of parasite protection needed is not the same for all dogs. 

Parasite protection needs to match the needs of the individual dog:

  • To ensure the dog gets protection against the parasites its likely encounter
  • To ensure the dog gets the correct level of roundworm protection 
  • To avoid giving the dog unnecessary medicines
  • To ensure that the type of parasiticide product is best suited to the dog and its owner, so it is more likely to be used and be effective. 

All dogs need protection against fleas and roundworm. 

Many dogs carry roundworm (Toxocara canis) and have the potential to shed it in their faeces. This is a threat to human health because roundworm can be transmitted to humans and cause potentially serious disease. It's difficult to know if a dog carries roundworm and so all dogs should be wormed at least every 3 months with a product that is effective against roundworm. But some dogs should be wormed every month. These are:

  • dogs that catch prey, because this makes them more likely to be infected with roundworm.
  • dogs that live in a family in which there are children under the age of 5 years, or a person who has a weak immune system because of a drug treatment or a disease. These people are more susceptible to being infected with roundworm.

Cat fleas (the type of flea that usually infests dogs) are present all over the UK. Even indoor pets can be affected by fleas carried into the home on clothing or other materials. Although fleas are more common in the warmer months, it may be possible for fleas or flea larvae to survive all year round because of warm winters or central heating. As it can take at least 3 months to get rid of an established flea infestation in the house, prevention of fleas is usually preferable to cure and veterinary parasite specialists recommend that all dogs should have routine year-round protection against fleas.

As well as basic protection against roundworm and fleas, some dogs will also need protection against one or more of the other three main parasites - ticks, tapeworm and lungworm (Angiostrongylus vasorum).  Press the play button below to listen to an interview with vet and parasite specialist Ian Wright, President of ESCCAP UK & Ireland, who explains why parasite protection is necessary and which parasites pet owners should be concerned about.


The following five questions will help determine the level of roundworm protection needed, the need for protection against the other main parasites, and help determine the most suitable form of product. 

Q1: Is your dog in regular contact with young children, or a person with a condition or on medication that suppresses the immune system? These people are more susceptible to roundworm infection and so monthly rather than 3-monthly roundworm treatment is recommended to ensure roundworm is suppressed in the dog.

Q2: Have you ever found a tick on your dog? A history of tick attachment strongly suggests that the dog's lifestyle exposes it to ticks. Dogs walked in environments likely to contain ticks (e.g. long grass in areas near cows, sheep or deer) are at risk. Regular use of a product containing a drug that kills or repels ticks is recommended.

Q3: Does your dog eat raw food, including offal, or catch prey? These dogs are more likely to pick up tapeworm or roundworm and so regular treatment with a drug that controls tapeworm is recommended as well as monthly roundworm protection.

Q4: Does your dog eat slugs, snails or grass? The dog might be at risk of the lungworm Angiostrongylus vasorum infection. This also depends on whether the infection is present in the local area. Drugs to prevent this lungworm are only available from a vet, and so the dog owner should be referred to a vet for advice.

Q5: Do you bath your dog, or does it swim, or does your dog have an allergic skin disease or react to products applied to the skin? A tablet formulation might be more suitable than a spot-on, or a water-resistant collar might be an option.


You can listen to a complete podcast of the module below by pressing play or use the download link on the right hand side of the player to download the podcast to your mobile device.

Test yourself

To do the CPD quiz and receive your certificate, you will have to hit the play button on the player below and enter your name and email address before you start.


Committee for medicinal products for veterinary use, 2008. Guideline for the testing and evaluations of the efficacy of antiparasitic substances for the treatment and prevention of tick and flea infestation in dogs and cats. European Medicines Agency.

European Scientific Council Companion Animal Parasites. Control of ectoparasiticides in dogs. ESCCAP Guideline 03 Third edition, September 2015.

European Scientific Council Companion Animal Parasites.. Worm control in dogs and cats. ESCCAP Guideline 01 second edition, September 2010.

Epe C. Intestinal nematodes: biology and control. Vet Clin North Am Small Anim Pract 2009, 39:1091-1107. 4.

Traversa D. Pet roundworms and hookworms: a continued need for global worming. Parasites Vectors 2012; 5: 91. 5.

Wright I, Wolfe A. Prevalence of zoonotic nematode species in dogs in Lancashire. Vet Rec 2007; 161: 790.