Parasite Prevention

Parasites can pose serious health risks not just to pets, but to people too

Parasites can pose serious health risks not just to pets, but to people too. It is vital to treat your pets regularly for parasites. Speak to us to help decide what parasite prevention plan is best for your pet.

  • How does my pet become exposed to worms?
  • My pet seems healthy and I haven’t noticed any worms in my pet’s faeces, do they still need treating
  • How do worms affect people?
  • What are the parasites I need to consider treating dogs and cats for in the UK?
  • Roundworm
  • Tapeworm
  • Lungworm
  • Fleas
  • Ticks
  • What are the options for treatment?
  • I am planning on taking my pet outside the UK. Are there any other parasites I need to think about?
  • What about exotic pets such as rabbits and tortoises?

How does my pet become exposed to worms?

There are many ways pets can be exposed to worms. Some can be passed in faeces which can then be spread in the environment and even carried into your house on your shoes.

Infestation from other types of worms can occur from eating slugs, snails or fleas.

My pet seems healthy and I haven’t noticed any worms in my pet’s faeces, do they still need treating

Cats and dogs can look healthy, even when they have worms. Often only the eggs will be passed in the faeces. These would only be visible under a microscope.

Different worms pose different risks but some can cause serious illness or even result in the death of a pet. These symptoms can come on quickly and by the time the signs are severe can be very hard to treat.

How do worms affect people?

Some worms can pass from pets to people through grooming, stroking or the environment. Rare cases can lead to serious conditions such as blindness or seizures.

Children, the elderly and those with reduced immune systems are most at risk but people of any age can be affected.

What are the parasites I need to consider treating dogs and cats for in the UK?

There are many parasites which can affect your dogs and cats. Some of the more common ones which require routine preventative treatment are discussed below.

Others not discussed and which may need treatment include mites such as: 

  • Sarcoptes and Demodex
  • Lice
  • Hookworm
  • Whipworm
  • Protozoa such as giardia

other types of lungworm than Angiostrongylus vasorum, e.g.: 

  • Crenosoma vulpis and Oslerus osleri in dogs
  • Aelurostrongylus abstrusus in cats


Roundworms are large white worms, with cylindrical bodies. The adult roundworm lives in the small intestine and feeds on gut contents.

Pets can contract roundworm by swallowing infected eggs from the environment. Puppies can be born infected with roundworms which have passed across the placenta. Kittens and puppies can also become infected via their mother’s milk. If your pet likes hunting, they can also be infected by eating prey.

Often there are no outward signs of infection but symptoms can include a pot belly, poor coat, diarrhoea and poor growth.

Disease is not common in humans, however when it does occur it can be serious because larvae can migrate within body tissues and they can reach the eye which can cause blindness. As a result we recommend monthly treatment for roundworms especially if there are children in the family or your pet goes outside regularly.


Tapeworm look like long, flat ribbons or tapes, divided into segments. The adult tapeworm live in the small intestine. Once mature the tapeworm releases segments (they look like rice grains) containing eggs. These pass out in the faeces.

Cats and dogs contract tapeworm by eating an intermediate host which has tapeworm larvae living inside it. Intermediate hosts include fleas, which can be ingested while grooming and small mammals which can be ingested if your pet hunts or finds a dead one.

If your pet has a tapeworm infection, you may see the segments in the faeces or around your pet’s bottom. However you may not realise, as cats and dogs infected with adult forms of the tapeworm often show no symptoms. If symptoms do occur they can include diarrhoea and irritation around the pet’s bottom from the segments.

We recommend 3 monthly treatment for tapeworms, however, animals may need tapeworm treatment more often if they frequently hunt or scavenge or your pet has contracted fleas.


Lungworm (Angiostrongylus vasorum) is a risk to dogs. It does not infect cats. The adult worms live in the heart and pulmonary arteries and so won’t be seen in the faeces. The larvae, which are passed out in faeces, can only be seen with a microscope.

Dogs can become infected with this life-threatening parasite by swallowing intermediate hosts. The intermediate hosts of lungworm are slugs, snails and frogs. Even if dogs don’t eat slugs and snails on purpose (which some do!) they can accidently by chewing grass or sticks, drinking from outdoor water bowls, or playing with toys outside. Symptoms can include coughing, tiring easily, weight loss, poor appetite, vomiting, diarrhoea, bleeding and seizures. Lungworm can be fatal.

Lungworm cases have now been confirmed in our area so we recommend monthly treatment with a lungworm preventative product.


Fleas are small, wingless insects. 95% of the flea population is in the environment as eggs, larvae and pupae. Adult fleas live on the animal and feed on blood. They lay their eggs on the animal which then fall into the environment where they hatch into larvae. The larvae then pupate before emerging as an adult flea which jumps on to your pet to feed. Environmental stages can survive for many months. It is, therefore, important in infestations to treat environmental stages as well treating the adults on the pet for many months to fully control the infestation.

Fleas can cause irritation through their bites and saliva. In some cases severe skin infections and intense itching can be seen if the pet is allergic to the flea saliva. This is called Flea Allergic Dermatitis. A very heavy infestation particularly in small animals i.e. kittens and puppies can lead to anaemia. Fleas can also be responsible for the transmission of viral and bacterial disease. In a heavy infestation, fleas may also bite people.

We recommend monthly treatment against fleas. Regular prevention rather than just treating when your pet gets fleas will stop environmental stages building up in your home.


Ixodes ricinus is the most common tick in the UK. They are most commonly found in rural areas but recent studies have showed a surprisingly high level in urban areas too. They lie in vegetation and attach to dogs or cats as they brush past.

They can cause reactions at the site of attachment and may even cause anaemia if there is a severe infestation in a young animal. In the UK, they can transmit diseases such as Lymes Disease.

Serious, life-threatening diseases such as Babesiosis and Ehrlichioisis can be transmitted to pets travelling abroad, therefore regular tick treatment for travelling pets is especially important. Recently there have been isolated cases of Babesiosis in dogs in the UK that have not travelled abroad.

What are the options for treatment?

There are lots of different parasite prevention products on the market and unfortunately there is no one product that treats all of the parasites. We recommend speaking to us to discuss the most appropriate program to protect your pet and your family. This will be based on their lifestyle. There are also many different formulations from oral medications, “spot-ons” and collars and we can discuss what combination you might find easiest.

We recommend caution in using over the counter products as some are not as effective as licensed products and also it can be confusing working out if your pet is fully protected. For example some worming products will say they cover lungworm when they mean Oslerus osleri and not the potentially fatal Angiostrongylus vasorum.

I am planning on taking my pet outside the UK. Are there any other parasites I need to think about?

We are very fortunate in the UK not to have some of the nastier parasites or the diseases they can transmit, that are found in other parts of the world.

If you are travelling with your pet, we would recommend seeking veterinary advice to discuss preventative care before you go.

What about exotic pets such as rabbits and tortoises?

Exotic pets can get several types of parasites and there are so many species of exotic pets that it is not possible to discuss all of them here, however, in these species there can be risks associated with certain parasite treatments. As a result the benefits of treatment need to be weighed against the risk of infection.

Speak to the exotics team for the recommendations for your species. Often faecal testing will be recommended prior to treatment.

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