External Parasites

Pesky Parasites

Parasites can be a pain for pets as well as for people around them. Not only can they cause skin and digestive problems but there are also some parasites out there which can be fatal. We’re going to focus on how to spot a parasite problem and parasite prevention for your pets.

External parasites

External parasites or ectoparasites is a term we use for anything living outside of your pet’s body. This can include mites, lice, ticks, fleas as well as flying insects. There are many ways to treat and prevent these parasites. Treatments can vary on how you give them, how often they are needed, how long the treatment lasts and the cover over different parasites for your pet. It is well worth discussing with your vet what the best option is for your individual pet’s needs.


  • Fleas – Fleas are external parasites that live in your pet’s coat and bite your pet’s skin. They are normally brown and 1-2mm long. They can jump and a single flea can lay up to 50 eggs a day. There are different types of fleas depending on their host species but they’re not always that picky. Often it is the cat flea that jumps onto our dogs and we can be bitten by fleas too. You may see the fleas, their droppings through your pet’s coat, small red areas which are the bites or evidence of scratching/itching done by your pet in response to the bites. The good news is flea treatment normally covers all of the different types of fleas.
  • Mites – Mites are microscopic parasites that live on your pet’s skin. They come in two types – burrowing and surface mites.

Scabies or sarcoptic mange is caused by a burrowing mite which can cause intense itching and is highly contagious. Normally we see scabs, self-trauma from pets itching and hair loss. Another burrowing mite is called Demodex which affects hair follicles and causes hair loss. This parasite lives on animals without causing problems most of the time. However if an animal is unwell or is weaker (e.g. growing or getting old) then the mites can get out of hand and cause hair loss, itching, redness and thickening of the skin.

Cheyletiella is a surface mite and is often known as walking dandruff. This mite can affects multiple species including rabbits and guinea pigs. You may see scurf and dandruff building up or the hair may fall out. Another common surface mite is the ear mite which is also known as Otodectes. These mites can be seen as small white dots moving round in the pet’s ear canal and cause excessive wax build up.

  • Lice – Lice are visible without a microscope and can cause intense itchiness for your pet. They don’t move very quickly and are transmitted via direct contact with another infected animal or through brushes, combs or bedding. There are two types of lice – a sucking louse and a biting louse and they have adapted features depending on how they feed. Animals with a louse infestation will often have a dry, rough hair coat.
  • Ticks –Ticks are common in the UK, especially in the Spring and Summer. It is normally the sheep tick or the hedgehog tick which affect our pets. Ticks are commonly found in shrubbery, long grasses or low lying branches. Female ticks can lay up to 2000 eggs which are only 0.7mm long but develop into adult ticks the following year. These attach to their host and then can fall off after they have fed from the animal’s blood. This normally takes around 1 week. Ticks are easily found once they have had a feed and are grey in appearance. Usually they are found on the lower abdomen, legs or head areas from when they’ve been picked up but can be anywhere on the pet.

Whilst ticks are easily treated and can be removed with special tick removal hooks, they can transmit more serious diseases. Lyme’s Disease, Ehrlichiosis and Babesiosis are all passed on by ticks. Lyme’s disease can cause flu like symptoms with a bull’s eye mark on around the site of the tick bite. Ehrlichia and Babesia both affect the blood cells. If you find ticks on your pet, it is always worth getting them checked over by your vet to ensure correct removal of the tick and that there are no ongoing problems.


  • Flying Insects – Flying insects in the UK may cause annoyance to our pets but it is when travelling abroad that our pets are more at risk from these creatures. In some European countries sandflies and mosquitoes will pass on serious disease such as Leishmaniasis and Heartworm. In the UK we only see these diseases in imported dogs but if you are planning on travelling with your pet abroad always discuss preventative treatments well in advance for your pet.

Bees/wasps can still cause problems for our animals with stings and sometimes this can result in severe swellings. If you suspect your pet has been stung it is best to phone your vet for advice and they may advise a consultation and medication to be administered. Always remember fly prevention treatments in rabbits and regularly handling and checks in all small animals. Flystrike is still sadly relatively common and the best prevention of this disease is achieved by frequent checking along with an appropriate insecticidal treatment.

General Advice for External Parasites

  • Ensure your pet is covered with an appropriate ectoparasite treatment and that there are no lapses in treatment cover.
  • Discuss with your vet about the ectoparasite treatments available. It may be that combined treatments or longer acting preparations may be more suitable. Treatments may come as a tablet, liquid for topical application or sprays. Always remember to treat the environment too if that is needed.
  • Don’t give up. If you struggle to apply or give the ectoparasite treatment then speak to your vet clinic. Most practices run nurse clinics which can help with application of these products and give hints or tips on how to give these at home.
  • NEVER give any or apply any permethrin containing products to a cat or animals in close proximity to cats. These are highly toxic to cats and so must be avoided in this species.
  • Don’t forget our small animals – regular checking and handling is the best way to pick up if there are any problems.
  • If you’re planning on going out of the UK with your pet speak to your vet as soon as possible. They will advise of the ectoparasite treatment required along with vaccinations, potential blood tests and any other medications required.


We hope you have found this information useful. Next week we focus on internal parasites for your pets.

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