How Can a Pet Get Parasites?

How can a dog get parasites.

There are many parasites that your pet may be susceptible to, which can be caught and spread through various means. Here is a list of some of the most common types of parasite that may afflict your pet.


These live in the gut and are distinguishable by their teeth and cutting plates, with the ability to grow between 5 and 16mm in length.

A bitch can pass them on to her puppies, and adult dogs can get become affected by ingesting larvae. It may be present on the fur, skin or in animal faeces, with foxes in particular carrying a potential risk.

Larvae can also enter the body through the skin, especially via the feet, and small animals that dogs or cats could eat can carry the parasite.


This parasite lives in the small intestine and survives by feeding on the contents of the gut.

The large white worm with a cylindrical body is spread when an animal eats infected eggs that may be found in the environment.

A lot of puppies are also born with roundworm, or contract it from their mothers through nursing. Additionally, eating an animal that is playing host to it is another way of becoming infected with it.


This type of worm is characterised by the whip-like appearance of its tail. They live in the intestine and feed on blood and tissue in the lining.

As with hookworms and roundworms, they are transmitted by consuming eggs. These may also be present in animal faeces, and on animal skin.


Their name is a reference to the worm’s thin ribbon or tape-like appearance, and they live in the small intestine. Their eggs are passed out of the body into the faeces of dogs or cats.

Fleas can carry tapeworms, so this type of parasite may be contracted if licked off the skin. They may also be spread in animal faeces, or via another animal host.


Although their name suggests otherwise, lungworms reside in the heart and can be deadly for dogs. The parasite is transmitted when animals eat slugs and snails, which can carry it. The microscopic larvae are passed out of the animal via the faeces.

Fox lungworm

Fox lungworm affects both dogs and foxes and lives in the airways of the lung, potentially growing to 14mm in length.

Foxes shed larvae into the environment, whilst slugs and snails can also harbour the parasite.


Although not currently present in the UK and Ireland, heartworm can present a problem when travelling overseas with pets.

It lives in the pulmonary arteries and the right side of the heart, and can be spread via mosquito bites.

Dirofilaria repens

This type of worm is passed on through mosquito bites. They are a potential threat overseas, but not currently present in the UK or Ireland.

They live in the subcutaneous zone under the skin, can grow up to 17cm long and travel in the bloodstream when in the larval stage.

Spirocerca lupi

Again this type of worm is not present in the UK, but can be a problem for pets travelling to South Africa and other areas around the world.

They live in the oesophagus and aorta, the main artery in the body, and are contracted when pets swallow small animals such as beetles or lizards that have it.


These minute arachnids live in long grass and vegetation, particularly in rural areas.

Dogs walking through it can find themselves the victims of ticks that attach to their skin and feed on their blood. Outdoor cats are also susceptible, depending on where they roam.

Ear mites

Ear mites are tiny arachnids that live on the surface of the ear. They are highly contagious, and can easily pass between animals via direct contact.


These ‘cigar-shaped’ mites live on the skin and can affect dogs and cats, although they are more commonly found in dogs.

The only time they can be caught is by the mother transferring them to her puppies, and they aren’t contagious after this stage. They will, however, live on the skin of an infected animal for the rest of their lives.

Sarcoptic Mange Mite

These highly contagious eight-legged mites infect their host with mange, and can be contracted through direct contact with an infected animal.

Notoedric Mange Mite

As with the sarcoptic mange mite, this type of parasite is also responsible for mange, and can be transmitted via direct contact with a cat that has them.

Biting lice

This small insect lives out the entirety of its life on the host animal, and can be transferred through direct contact.


These small wingless insects are able to jump 100 times their own height, and feed off blood.

Eggs laid on the animal fall off and spread into the environment, so the majority of the flea’s lifecycle is spent off the host. Fleas can be caught from infected animals, or areas they are present in. This is why treating the home after the discovery of an infestation is extremely important.

If you think your pet may have parasites, take them to the vet for treatment as soon as possible.

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