Quick A to Z of common external parasites in cats

Common external parasites of cats

Fleas

Fleas are the most common type of external parasite of the cat, and the most common type of flea found on both cats and dogs is the cat flea (Ctenocephalides felis). Fleas are small wingless insects that live on the coats of cats, and they can live for up to 2 years!

Female fleas take a blood meal from the cat (bite them), and then lay their eggs - which can be up to 50 eggs per day! The eggs fall off the cats’ coat and remain in the environment (the home) until they hatch and become larvae which can be as little as 2 days.

The larvae feed off the flea dirt (which is flea poop) and remain in bedding, carpets and cracks in the flooring where they lodge themselves deep down as they dislike light and they can lay dormant for up to 2 years, only reactivating in response to vibrations, temperature and the presence of carbon dioxide which all indicate a person or animal is nearby to jump onto once hatching.

Signs of fleas include scratching, finding flea dirt in their coat or where they sleep and seeing live fleas. Fleas can also transmit one species of tapeworm to cats, so you may see signs of tapeworm on top of the faeces or crawling around your cat's bottom.

Ticks

Ticks are 8 legged parasites which attach themselves to a host to feed on blood via a bite through the skin, and are most commonly found in long grass and woodlands.

They can bite many mammals such as humans, domestic pets like cats and dogs and many wildlife species such as deer or hedgehogs.

Unfed ticks are very small, but engorged ticks swell up and are easily recognisable as a grey lump around the size of a pea. Ticks can transmit diseases to cats including Lyme disease or babesia.

Ticks once fed are fairly easy to spot on your pet and they usually attach around their head / neck and limbs. They can be removed using a special tick remover which encourages the complete removal of the tick including the mouth parts. Do not grab the body and squeeze the tick, as you risk injecting the tick contents back into the skin of the cat and they must be removed carefully with a twisting motion to not leave the mouthparts behind.

Harvest Mites

Harvest mites is the name given to the larval stage of the adult mite called Trombicula autumnalis. The larval stage of this mite can live on humans, cats, other mammals and birds. Only the larval stage causes parasitic infection. The larvae feed on tissue fluid and cause intense skin irritation. They are orange in colour and just about visible to the naked eye.

The larvae are present in long grasses and vegetation in the dry summer months and await the presence of a warm cat body to pass through. They swarm onto the cat and congregate on areas where there is thin hair coverage such as the ears and above the eyes. When the larvae feed on the cat, they inject a fluid to break down the cells. This fluid can cause severe irritation to the skin resulting in dermatitis.

Ear mites

Ear mites are quite common in young cats and kittens. The most common ear mite to affect cats is called Otodectes Cynotis, and they are just barely visible as tiny white dots to the naked eye. These mites live inside the cat's ear canal and feed on wax and debris. They cause a lot of irritation and inflammation of the ear canal. They are passed on through close contact with infected cats but can also be acquired from the environment. They are common in kittens when the mother cat has ear mites. Signs include scratching at the ears, crusty discharge in the ear, head shaking and red painful ears (all these signs can also indicate an ear infection).

Mange mites

The mange mite that can affect cats is called Notoedres cati. It is a type of sarcoptic mange that causes incredibly itchy skin and crusting. They generally affect the ears and face, but if not treated will spread to the rest of the body. These mites can also spread to humans and other animals, but luckily infection with this mite is quite rare in the UK.

Lice

The only cat louse present in the UK is called Felicola subrostratus, which is a type of chewing louse (as opposed to a sucking louse). They spend their entire lives on the cat and can only survive in the environment for a few hours. Lice infestations are quite rare in cats in the UK, but signs to look for include visible “nits” in their fur or visible adult lice, itching and patchy hair loss.

Flystrike (Myiasis / maggots)

Not very common fortunately but still something to be aware of in cats. If your cat has an open wound / urine scalding / soiling of the fur, this can attract the interest of flies more commonly in the summer months during warm weather. Flies will lay their eggs on the cat's fur or in their wounds and the eggs appear as small flecks or grains on the fur. The eggs then progress to the larval stage which is maggots. Maggots can cause a lot of tissue damage and urgent treatment is required in cases of flystrike - it can be life threatening.

Many of these parasites can be prevented with appropriate measures, and what treatments are used are dependent on your cat's risk factors and lifestyle. Remember it's important to check your cat regularly for signs of external parasites as no product is 100% effective, particularly tick prevention.

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This article was written by Amy Everden RVN, CSQP, ISFM CertFN. Amy is a registered veterinary nurse (RVN) who has worked in a variety of first opinion and 24 hour veterinary hospitals. In 2019 she completed her certificate in Feline Nursing with distinction.