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Fleas in cats and dogs

Most cat and dog owners over the summer months will notice that their pets begin to scratch and itch. When asked about flea treatments, many will reply - my cat/dog has no fleas. On closer examination, there will be tiny black specks throughout the animal's coat which is a clear indication that there are fleas present.

These black specks or "flea dirt" are actually flea faeces - fleas are blood feeders. they bite the dog or cat to feed on their blood. The blood, once digested through the intestinal system of the flea, comes out as little black dots.

So why do some animals scratch while others are totally unaffected? Many dogs and cats are actually allergic to the flea bites and will become itchy soon after being bitten. Only a few bites are needed to start the itch/bite cycle and often you may not even see the fleas that start the problem. However, once the animal starts to scratch, he aggravates the skin and it becomes more itchy, he scratches more and a vicious cycle begins so that there is hair loss and inflamed skin and eventually a very irritated pet!

How do we treat the problem? In severe cases we need to put the animal on medication that will help relieve the itching. However it is preferable that we do not get to that stage in the first place. This can be achieved by regular and frequent flea treatment. There are many types of flea treatments available from rinses to shampoos, to sprays or tablets. each has it's advantages and disadvantages and there is a large difference in prices too. The following pages examine some of the products available at this clinic.

Never say that your pet has no fleas! In most cases if your pet is scratching and chewing, especially over the summer months, there is a high chance that it is due to fleas even though you may not see any. It is important to be regular with your flea treatment and this will help keep the fleas under control.

Facts about fleas 


  • Most common and successful parasite of dogs and cats.
  • Difficult to control without a planned approach.
  • Most common cause of allergic skin problems.
  • Some animals are allergic to flea saliva and show skin problems despite no apparent evidence of fleas.
  • Fleas come from an infested environment, not animals.
  • One flea infested 'hot spot' area, not treated, may be enough to cause major problems.
  • Treat all animals in the household, and areas where they sleep.
  • Maintenance important to avoid reinfestation from external sources.

Adult fleas

  • Once hatched, they must feed, so they actively seek a host.
  • Female lays 5-20 eggs at a time and 400-500 during her lifetime.
  • They leave dark grit on the host (digested blood) as food for the young.
  • Most of the life cycle is spent away from the host.
  • The entire life cycle 3 weeks - to months, depending on temperature and humidity.
  • Can jump long distances and readily attack themselves to animals moving through infested environments.

Flea eggs

  • Laid on the host and roll off into the environment.
  • Hatch in 1-10 days, depending on temperature and humidity.


  • Move down and away from light and traffic areas.
  • Live under furniture, in carpets/cracks/soil and especially near where your pet lies and sleeps.
  • This stage lasts between 5-11 days.
  • Heat and drying will kill them.


  • Difficult to control.
  • May live several centimetres below the soil, carpets etc where they are protected.
  • If warm and moist conditions prevail, pupae will emerge in 5 days and peak at 8-9 days.
  • If protected from drying, pupae can survive for up to 140 days in the environment.

Pre-emerged adults

  • They can hatch in less than one second.
  • All fleas reach this stage then hatch when stimulated, for example vibration, which results in "plagues" after you return from holidays.

Flea control methods

Vacuum, clean and groom

  • Removes some fleas, eggs and grit.
  • Allows better chemical penetration, therefore you can use less of the product.
  • Dispose of vacuum dust in sealed bag.
  • Ensure coat is not matted as this protects the fleas.

Wash bedding weekly

  • Wash all bedding and hang out to dry, sunshine is effective and free.
  • Avoid thick padded cushions which absorb and protect fleas. Outside: treat sheltered moist spots.
  • Fleas will die if exposed to sunlight and are in a dry environment.


  • Read all labels carefully.
  • Do not use 2 or more products at once without veterinary advice.


  • Kills adult fleas only.
  • Usually only effective for 2-3days so needs frequent reapplication.
  • Usually safe for animals and bedding.


  • Mostly kill adults only.
  • Vary in strength and toxicity.
  • Usually only effective for 2-3 days so need frequent application.


  • Can be useful.
  • May control growing stages of fleas for up to 6 weeks.
  • Vary in effectiveness and price considerably.

Fogger bombs

  • Vacate premises during and 2 hours after use.
  • Kills build up of fleas and controls breeding.
  • Move furniture to expose places where young fleas hide.
  • Cover food, fish tanks and clear plastic eg stereo covers with newspaper.
  • Vacuum first.
  • Turn off all pilot lights eg gas heater, and electrical appliances including refrigerators as bombs are flammable.

Frontline top-spot or spay

  • A monthly topical spot on for dogs and cats or insecticidal spray which lasts for 3 months in dogs and 2 months in cats, the volume required is dependent on the size of the animal.
  • Also controls paralysis tick for up to 3 weeks.
  • Can be used in pregnant and lactating bitches, pups and kittens from 3 months of age.
  • Waterproof, even for weekly bathing.


  • Topical spot on flea adulticide.
  • Monthly application.
  • Bathing animal between each application lowers the duration of efficiency.
  • Safe on pregnant or lactating animals and can be used on puppies or kittens.


  • Provides fast short term relief from fleas. Fleas start to die within 30 minutes of administration and all fleas are dead within 7 hours.
  • One tablet lasts 24 hours.
  • Safe in pregnant, lactating animals, pups and kittens from 4 weeks of age.
  • Use for rapid relief from fleas.
  • Can be used in conjunction with other flea controls to kill persistent adult fleas when required.
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