Lesson 1: Why Fleas Are Bad


There are over 1900 flea species in the world.  We are concerned with only one: Ctenocephalides felis, the cat flea.  This is the flea that we find on our pets (cats, dogs, rabbits, and other species) in 99.9% of cases and in order to understand how to control the damage caused by this tiny little animal, you should learn all you can about it.

What Kind of Damage Can Fleas Cause?

It would be a grave mistake to think of the flea as simply a nuisance.  A heavy flea burden is lethal, especially to smaller or younger animals. The cat flea is not at all selective about its host and has been known to kill dairy calves through heavy infestation.  Conditions brought about via flea infestation include:

  • Flea Allergic Dermatitis
    (remember, fleas do not make animals itchy unless there a flea bite allergy)
  • Flea Anemia
  • Feline Infectious Anemia
    (a life-threatening blood parasite carried by fleas)
  • Cat Scratch Fever
    (does not make the cat sick but the infected cat can make a person sick)
  • Common Tapeworm infection
    (not harmful but cosmetically unappealing)

Remember that most pet owners have no idea that fleas can kill.

This is so important that we will say it again: Most pet owners have no idea that fleas can kill.  On some level, it is obvious that fleas are blood-sucking insects but most people never put it together in their mind that enough fleas can cause a slow but still life-threatening blood loss.  This is especially a problem for elderly cats allowed to go outside .  These animals do not groom well and are often debilitated by other diseases. The last thing a geriatric pet needs to worry about is a lethal flea infestation and it is especially important that these animals be well protected.

Also consider that in about 90% of cases where the owner tells us the pet does not have fleas, we find obvious fleas when the animal is flea combed.  Despite the TV commercials, the educational pamphlets, the very common nature of the parasite, there are still some very large awareness problems in the public and a multitude of misconceptions.

Flea Myths You Will Hear:

  • My pet cannot have fleas because he lives entirely indoors.

    (Fleas thrive especially well in the well-regulated temperatures of the home.)

  • My pet cannot have fleas because if there were any fleas they would be biting (insert name of someone in the family reportedly sensitive to flea bites). Since this person is not being bitten, there must not be any fleas.

    (Despite Ctenocephalides felis’  ability to feed of a wide variety of hosts, this flea definitely prefers not to feed on human blood unless absolutely necessary.  A newly emerged adult flea is very hungry and may well take a blood meal from the first warm body it finds.  An adult flea knocked off its normal host will also be very desparate to find a new host and may feed on the nearest warm body it can find. In general, adult fleas regard human blood as a last choice and humans tend not to be bitten unless flea population numbers are high.)

  • We do not have fleas because we have only hard wood floors.

    (Fleas love to develop in the cracks between the boards of hard wood floors.)

  • My pet cannot have fleas because I would see them.

    (One cannot expect to see fleas as many animals are especially adept at licking them away. Sometimes all we see is the characteristic skin disease.)

Always remember when taking a flea control history to ask what product is being used and WHEN IT WAS LAST USED.  Many people will happily tell you they use Advantage® or Frontline® when, in fact, they have not used their product in many months.  When we ask someone what product they are using, we take for granted that we mean what product they are using right now. After a client tells you what flea product they are using, always follow up by asking when did they use it last?

Illustration of the point:  During an on-line consultation, a dog owner described lower back itching and dermatitis but did not believe the problem could be flea-related. What flea control product do you have?, I asked. They replied that they had Frontline. Frontline should be a pretty effective product so we went on to consider some possible causes other than fleas but at every turn it seemed that nothing was more likely than flea bite allergy. “How often are you using your Frontline?” I asked. “Oh, we’ve never used it,” they replied. “We just have it.” The moral of this story is to always asked what flea product is being USED and to let people know they need not ever see an actual flea to have a flea problem.

Your job is to educate pet owners as only through education will they will become successful in managing their flea situation.

Last updated: August 31, 2002