Fleas and other Uninvited Visitors

By E.G.D.McCarrison BVMS MRCVS



No matter how careful and pampered your cat is, it is almost certain that at some stage your beloved pet will pick up some fleas. Does this matter? Well, apart from the discomfort to your cat, these tiny creatures can easily get onto you and cause some very irritating itchy spots. We also know that many cats develop moderate to severe allergic reactions to the flea bite which can lead on to significant skin problems, including hair loss and infection.

It should also be remembered that fleas can carry various diseases. These include bacterial diseases which may affect the heart but the most common is a microscopic parasite which gets into red blood cells and destroys them – causing an anaemia. Fleas also carry the eggs of tapeworms which go on to live in the gut of your cat……see: www.feline-friends.org.uk/topics/worms-in-cats/

This is therefore one of those situations where prevention is not only better but also much easier than the cure.

A Flea’s Life Cycle

Let’s have a look at the life cycle of the flea, because this makes it clear why continuous prevention is always the best policy.

The first and most important fact is that only about 5% of the flea population are adults so even if you only see one flea on your cat there are potentially many more in the environment – in other words your cat’s bedding and around your house.

An adult female flea can lay up to 200 eggs in her lifetime and these eggs fall off your pet onto the bedding, furniture and carpets. After a short time (which can vary from a few days to several weeks) these eggs hatch and larvae emerge. The larvae eat debris found in the carpet and soft furnishing, and after about 2 weeks they turn into pupae. Pupae are very much like caterpillars which pupate – ready to change into butterflies. These pupae (which are pretty immune to chemicals) will only hatch – allowing the next generation of adults to emerge – when the conditions are right.

These conditions include a warm environment, or if a house has been vacant for a little while, such as during a holiday, any vibrations of footsteps on your return will encourage the eggs – hidden in your carpets – to hatch and can produce a sudden explosion of adults.

This why, when you collect your pet from the cattery, it appears that they have come back with fleas whereas it may well be that there was a reservoir of fleas in your home just waiting for the right conditions and this can be anything from a few days to over a year.

Prevention and Control

Okay, so knowing the above, how can we prevent or control the fleas so they are not a problem?

Killing adult fleas once they are found is obviously the first step that owners will want to do, so what is available?

1. Shampoos – Not suitable for cats, and are not very effective anyway.

2. Flea collars – Some can be effective but there is a huge variation in effectiveness and great care needs to be taken NOT to use dog flea collars containing Permethrin for cats. These can be fatal for cats.

3. Flea Powders and Sprays – Again there is a great variation in these products, and they are not considered suitable for cats. Most cats hate the noise of a spray anyway !!!

4. Injections – There is an injection available from your vet but be aware this does not kill the adult flea and will only prevents any eggs it lays from hatching. Although these work well they have to be used as part of a much wider control programme.

5. Tablets – These can be highly effective and yet again there are several different tablets available – but most are only for dogs. They are also ‘prescription only’ so please check with your vet. Administering to cats can also be problematic.

6. Topical spot on – In my opinion these are by far the easiest and most effective way of dealing with adult fleas. Most cats will tolerate the application of these products and an added advantage is that many of them are also effective against other parasites such as ear mites and roundworms. You must remember however that there is now a vast range of these products, all with differing chemicals, and not all are equal in effectiveness. It is best to get advice from your vet before using these.


If we consider however that up to 95% of the flea population are not on your pet but in the environment then, to be effective, we also have to treat the house as well.

Controlling the environment involves washing the bedding, regular daily vacuuming and using household sprays. Most of these sprays will protect the environment for up to 12 months but do not use them near fish as most are highly toxic to them.

Also, do not think that fleas are not a problem in the winter months. Our lovely centrally heated homes are ideal for fleas to breed right throughout the year.

Now, would it not have been easier to stop that first flea ever getting near your cat? In my opinion regular monthly application of a good effective flea spot on is by far the best course of action.


Other uninvited Visitors

I now move on to the various other visitors that can live on or in your cat’s skin. I will start with those that are more common than others, and work down to the occasional and less likely.


Mites are not insects but are related to spiders. They are usually microscopic although there are some just visible to the naked eye. They tend to be contagious and require close contact to spread from one cat to another or by contaminated grooming equipment. There are several different types of mites as listed below:

Ear Mites

These are surface-dwelling mites that live on the wax deep in the ear canal and are the commonest and least worrying type of mite. They are very irritating to your cat and will cause him/her to shake their head and scratch at their ears, sometimes causing quite a lot of damage to the skin on and around the ear flap.

Fortunately, if they are spotted early, it is relatively easy to treat ear mites with ear drops, or sometimes by applying a spot-on to the cat’s skin which will eliminate the mites very quickly. It is important when you get a new kitten that you check their ears very carefully because they will often pick these up while suckling their mother.

Harvest Mites

These are another skin irritant that are, as the name suggests, a seasonal problem.  Seen mainly in late Summer or Autumn these mites are usually found around the ears and head. They bite the skin and feed on the tissue fluid leading to reddening and crusting of the skin. Topical flea spot-ons are usually effective although sometimes steroids and antibiotics are required if a secondary infection occurs.

Cheyetiella Mites

Also called walking dandruff – these live on the surface skin scales leading to a lot of dandruff and an itchy area. If you look very closely these mites are just about visible to the naked eye and tend to be in patches rather than widespread.

Mange mites

Relatively uncommon in cats, there are 2 different types: Demodectic and Sarcoptic. Demodectic mites live in the hair follicles causing itchiness, scales and irritation and occur mainly around the ears and feet.  Sarcoptic mites burrow down into the skin and is sometimes called ‘fox mange’ since they tend to be the commonest source for your cat. It is important to know that this type is contagious to humans, so take care when handling your cat during treatment. Both types require skin scrapings to be taken for a diagnosis and effective treatment can only be provided by your veterinary surgeon.


These again are not insects but related to spiders. They have 8 legs and a body that increases in size and darkens as they feed. When they first attach, they are small and grey in colour, but as they feed they enlarge and can get to about the size of a pea. They are collected by your cat when they are out exploring especially in long grass or undergrowth. The ticks hang on to the vegetation and grab onto the fur of passing animals. This is much more common in the Summer or Autumn months.

They are blood suckers and will often only stay on the body for a few days before falling off to hibernate till next year – when they will feed again. They are usually found around the head area but can be anywhere. The most important thing to know about ticks is that they can carry several diseases – including Lyme disease (which can be very debilitating)  and they will quite happily attach to humans as well as animals. So if you get flu like symptoms after having a tick attach to you, seek medical attention.

There are small tools available to remove ticks which can be bought in pet shops or pharmacists but if you are not confident in their use it is best to take your cat to the vets. The area where the tick was attached can become infected if any parts of the tick remain in the skin. There are specific skin preparations designed to deter the ticks attaching to your cat’s skin and these can be used alongside your usual flea preventions.


Infestation of lice in cats is not at all common. All lice are what is called host specific so cat lice have to live on cats but if you are handling a cat with lice, you may still get bitten by them, and get small itchy spots. They usually will cause your cat to itch causing broken hairs and sometimes secondary damage to the skin by the cat scratching and licking. If you look very closely at the fur, you may see their tiny translucent eggs stuck to the side of hairs.

Topical flea products will kill the adult lice but not the eggs (until they hatch), so multiple treatments may be needed. It would also be advisable to get rid of any bedding to ensure eradication.

This may have sounded like a long list of nightmares for your cat (and may have made your skin crawl), but rest assured that most cases are easily treated and preventative care will reduce the likelihood of any of these pests being a problem to either you or your cat.

"In my experience, cats and beds seem to be a natural combination."

Louis J Camuti, Doctor of Veterinary Medicine.