Fleas and how to prevent them

These pesky blood-sucking parasites are a year-round problem for our pets and they can be a real nuisance. They can really make your pet’s life miserable by causing symptoms ranging from minor irritation and scratching to hair loss, severe allergic reactions and anaemia (This is made even worse if they start biting the humans in the household as well!).

Fleas can be a huge problem for pet owners and once they are established in the home they can be quite difficult to get rid of, because of their complex life cycle. The adult fleas we see on our pets are only 5% of the problem; 95% of the flea life-cycle actually takes place in the carpets, floorboards and pet bedding in your home.

There are over 2000 species of fleas in the world, but thankfully only the cat flea (Ctenocephalides felis) and the dog flea (Ctenocephalides canis) are the main problems for our pets in the UK. We do however, tend to see more of the cat flea because despite the name, it is happy to infest dogs, ferrets and rabbits as well as cats.

A: Cat Flea B: Dog Flea

Flea Facts 

  • A female flea can lay around 20 eggs per day and up to 2000 eggs in her lifetime of 2-3 months!
  • A flea can survive around 100 days without a blood meal
  • The female flea can consume 15 times its own weight every day
  • A flea can jump approximately 100 times its length; that is around 7-8 inches vertically and 13 inches  horizontally! (equivalent to a human jumping 250 feet vertically and 450 feet horizontally)
  • Fleas are active all year round, especially since the vast majority of homes in the UK have central heating.

The Flea Life Cycle

  • The adult fleas live on and feed off the host animal – usually dogs and cats but we starting to see more rabbits and ferrets affected too.
  • The female flea begins laying eggs within 36-48 hours of her first blood meal. The flea eggs are not sticky so they drop off the animal into the home environment, such as carpets, bedding, floorboards and soil.
  • The flea larvae emerge from the eggs after 2-14 days (depending on the environmental conditions), and begin to feed off adult flea faeces and other organic debris found in the home. Flea larvae have 3 stages of growth and depending on the amount of food present and environmental conditions this stage lasts around 7-14 days (longer in some cases).
  • The larvae spin a silk cocoon and pupate; whilst in the cocoon the flea is at is most resilient and is resistant to insecticides.
  • The adult flea can emerge from its cocoon as early as 3-5 days or it can stay in the cocoon for up to a year, just waiting for the right conditions. Warm temperatures, vibrations and carbon dioxide emitted from passing pets and people will trigger them to hatch. Once hatched, they use their well developed back legs to get around and jump onto passing animals.

Problems Caused By Fleas

  • Scratching and biting. Fleas are irritating and cause most animals to scratch as they run through their coats (I bet you are feeling itchy right now, just reading this!)
  • Hair loss. Caused by scratching or over grooming
  • Skin infections. Caused by scratching or self trauma (biting)
  • Flea allergy dermatitis (FAD). Some animals are hypersensitive to flea saliva and suffer an allergic reaction when bitten. It can take only one flea bite to cause problems for these animals.
  • Anaemia. Fleas feed on blood and a heavy infestation can have a big impact on very young, elderly or ill animals
  • Tapeworms. Flea larvae can become infected with tapeworm eggs. When pet’s groom themselves they can ingest infected fleas and become host to this parasite. If your pet has fleas you should also make sure your pet is treated for worms
  • Myxomatosis. This is a serious disease in rabbits which can be spread by fleas and other biting insects.

How To Identify Fleas On Your Pet

  • Adult fleas are only a 1.5-3 mm in length and can be tricky to spot if there are only a couple causing problems on your pet. Gently part the hair of your pet’s coat to look for fleas.
  • The best way to tell if your pet has fleas is by checking for flea dirt (flea poop). Wipe a damp piece of cotton wool through your pet’s coat, going against the direction of the hair. This will hopefully pick up some flea dirt if it is present. Because flea dirt consists mostly of blood, once it is transferred onto the moist cotton wool, it dissolves and turns a lighter shade of red.
  • Alternatively use a flea or fine toothed comb to brush through your pet’s coat and then transfer the brushings onto a piece of damp kitchen paper.

If there are only a few adult fleas present you may not find any evidence of flea dirt in your pet’s coat.

Risk To Humans


Although humans cannot be permanent hosts for cat and dog fleas, it will not stop them biting us if the opportunity presents itself and there are no preferred hosts around. Some people can have a bad reaction to these bites, which causes the area to swell and become painful and irritated.

Preventing Fleas Is Far Easier Than Dealing With An Established Infestation

The degree to which you need to control fleas will vary depending on the individual pet’s lifestyle and the home environment. You might think that a pet kept entirely indoors would be at no risk of catching fleas, but don’t forget that it only takes a visit from one untreated animal, or a flea or flea egg hitching a lift with you, to trigger an infestation in your home, so even housebound pets may require flea control. Pets that routinely go outdoors will likely come into contact with fleas from time to time, and will require regular treatment.

Remember that only 5% of the flea problem is actually on your pet, the rest takes place in your home!

        1. Use a prescription flea product regularly on your pet

  • Most flea treatments are recommended to be given every 4-6 weeks, depending on the type but some injections for cats and Prescription flea collars can last for 6 – 8 months. You may find you need to use them less often as it will depend how much contact your pet may get with fleas.
  • There are many different flea products available for your pet including spot-on liquids, tablets, injections and collars. Some products will kill fleas as they jump onto your pet, some after the fleas feed on your pet and others don’t actually kill the adult flea but act like contraceptives to prevent flea eggs from developing. Speak to a veterinary nurse who can advise you on which type of product will work best for your pet.
  • Your pet should be weighed regularly to ensure the correct dose of treatment is being given each time.
  • Flea treatments are also available for rabbits and ferrets, so please ask at your veterinary practice for advice on suitable products for these smaller pets. It is recommended that if you live in an area where myxomatosis is prevalent, that even vaccinated rabbits should be treated regularly to prevent flea infestations. Pet ferrets generally only have problems with only cat fleas, however, if they are working ferrets they can also pick up fleas from other species.
  • Always make sure the flea product is suitable for your pet i.e. it is for the species and weight of your pet. Read the data sheet carefully as not all products are suitable for all species of animal.
  • NEVER use a flea product containing Permethrin on a cat
  • Be careful when using ‘home remedies’ to treat fleas, because the vast majority either do not work at all or will only affect adult fleas on the pet and not the other life stages in the environment and some may even be harmful to your pet. For example there is no scientific evidence that feeding your pet garlic will keep fleas away, there is however, plenty of evidence that giving too much garlic can be seriously harmful to your pet and may lead to stomach upsets, nausea and severe anaemia!

        2. Use a veterinary recommended household flea spray

  • This will prevent the flea eggs from developing in the home environment.
  • Some of these sprays will provide protection for up to a year.
  • Don’t forget to spray the car if you have one.
  • Household flea spray can be highly toxic to birds and fish, so make sure bird cages are removed and fish tanks are covered before you spray the room they are kept in.
  • Never use it on your animals!

Why We Recommend Using Prescription Flea And Household Treatments Rather than Non-Prescription / Over The Counter Flea Treatments

  • The Vet or Nurse can weigh and assess your pet and recommend a safe and effective product based on his or her individual requirements.
  • Some flea treatments are HIGHLY TOXIC to cats. We see cases of avoidable poisonings every year because well-meaning owners have misread a label, been sold the wrong product, or given an incorrect dosage.The prescription products recommended by your vet have been thoroughly tested and we know them to be not only effective but safe too.
  • Some over the counter products and ‘natural’ remedies contain ingredients that may not be as effective in the face of a flea infestation and in many cases, there has been no controlled research studies to prove that these products actually do what they claim to do. There is no evidence that garlic (or brewer’s yeast, for that matter) will control fleas on pets (although some people think it will).  It is also important to note that garlic can be toxic to pets.
  • If you want to try to  control fleas “naturally,” wash your pet’s bedding and vacuum pet areas daily to remove any eggs and developing fleas. Use a flea comb to catch adult fleas on your pet (you will need to do this every day) – put the adult fleas into a bowl of warm water, then pour down the drain when you have finished grooming.  It is very difficult to prevent fleas this way as you are unlikely to be able to break the life-cycle quick enough to prevent more eggs being laid.

It is worth remembering that you do not need to buy the prescription treatment from your veterinary practice if you don’t want to, you can ask your vet for a flea treatment prescription and buy the product online or from a pharmacy.

If you would prefer to use a non-prescription or ‘natural’ flea treatment for your pet, you can still check with a veterinary nurse regarding dosage and safety if you would like too.

NEVER use a dog flea product containing Permethrin on a cat. Dog flea products are highly toxic to cats and can cause neurological damage, seizures and even death

Kill the flea not the cat

If you would like any more information or advice regarding fleas or flea products please contact us on 01189 574488