Understanding Fleas Better

Posted on May 11th, 2016


Over the years, fleas have really become a major problem for people and particularly animals.

Controlling their spread has become of major importance not only for the irritation they cause, but also for the diseases they may spread.

This article is designed to help you understand the life cycle of the flea and how to better handle its demise.

I did not realize that there are more than 2000 flea species that have been identified throughout the world, and they all belong to the order, Siphonaptera.

A flea is a type of wingless insect that lives on the blood of birds and mammals and must suck the blood as a nutrient, in order to remain alive.

For the sake of this article, it will speak primarily about fleas, as they effect dogs and cats.

The dog flea genus and species is Cterocephalides canis.

The cat flea genus and species is Cterocephalides felis.

For your own information, the dog fleas is brown and much larger than the smaller, darker cat flea.

NOTE: This information only becomes important when you are trying to determine the source of the flea infestation.


The flea goes through four different changes called metamorphosis which includes the egg, larva, pupas and the adult.

It interesting to note that there is a difference in distribution of these various changes.

50% = eggs

35% = larva

10% = pupas

5% = adults.

I order for the flea to go through all these stages, there must be a host for the flea to suck blood from.

This appears to become more of a problem for us, because what we trying to visualize normally, is the adult flea, which is only 5% of the different forms of the flea that are present.


The eggs are produce in batches of 20 and remain as eggs from 2 to 20 days, before becoming larva.

These eggs normally are found where the pet sleeps, which also includes your pet sleeping with you.


The larva must eat to remain alive, and they normally eat vegetable matter, feces and dead insects.

Since the larva are blind, they prefer to habitat dark places, like cracks, crevices and under you or your pets, bedding.


The pupas usually exist for 2 to 3 weeks before they become adult fleas.

NOTE: Fleas tend to rest during the winter in a larval or pupa state. They can be stimulated to become adults with certain stimuli like vibrations, sounds, heat and carbon dioxide.


Did you know the life span of a flea can be from one to many years, if the right conditions exist?

A female flea can produce up to 50,000 flea eggs during her life time!

NOTE; Most of the fleas different metamorphic forms will be present where the host, dog or cat, sleeps or where the pet spends most of their time.

Wikipedia reported on a very interesting fact that may explain to me, why certain dogs and cats, with endocrine immune imbalances and nutritional deficiencies, seem to be more prone to flea infestations. This may also explain why a pet owner with more than one dog or cat, may have only one animal with chronic flea infestation and why all the other animals, seem to be flea free.

What Wikipedia has reported, that we find so interesting, is the following;

Adult female rabbit fleas, Spilopsyllus cuniculi, can detect changing levels of cortisol and corticosteroids in the rabbit’s bloodstream. This triggers sexual maturation in the fleas and cause them to produce eggs”.

I think what is really happening, is when the rabbit goes in to heat, and the estrogen levels increase, the fleas are attracted to the animals, in order to lay their eggs.

This is a natural cycle.

This would definitely explain why certain dogs and cats in one family that has other pets, have fleas, while the others do not have fleas, unless there is an overall flea build up.

Any dog or cat that has my endocrine immune imbalance that causes elevated amounts of adrenal estrogen, will be attractive to fleas.

This also may be the reason why most allergies of the skin of dogs and cats, are thought to be a flea allergy dermatitis, even though the owner of the pet is unable, to find fleas.

What we find also very interesting, is the fact that once the endocrine imbalance has been identified in these animals and corrected, which in turn corrects their immune regulation, these dogs and cats no longer show signs of a flea allergy dermatitis and no longer have fleas.

What is not recognized yet, is the fact that the endocrine system regulates the immune system, and when there is an imbalance, it will attract fleas and may enhance the flea’s ability to produce eggs.

Unfortunately, many chemical flea repellents can alter the cortisol levels in dogs and cats, including other hormonal alterations, and may be the reason that continued use of one chemical repellent, no longer works. For further information on this subject, please go to the article entitled. Chemical Insect Repellents on this website.



  1. Itching
  2. Swelling
  3. Inflammation
  4. Scratching
  5. Self-biting
  6. Red bumps from where the bite occurred
  7. Flea allergy dermatitis



  1. Murine and endemic typhus in humans
  2. Bubonic plague from rodents for humans
  3. Yersia in humans
  4. Rickettsia typhus in humans
  5. Rickettsia felis (cat flea typhus)
  6. Bartonella henselae in humans
  1. VIRUS
  1. Myxomatosis
  1. HELMINTHES INFESTATION (Tape worms) in dogs cats and humans
  1. Trypanosomes (protozoans)



  1. Chemical flea control products.

Please read my article for both you and your veterinarian on Chemical Insect Repellents on this website, and then decide which chemical will be the safest for you to use on your pet.

NOTE: Yeast and garlic usually does not work well in pets, because the yeast and garlic ends up in the sweat of humans and makes them less palatable to insects. Normally, dogs and cats only sweat between their toes and this why garlic and yeast normally does not work well as a flea or insect repellent.

In the old days, our clothes were stored in cedar closets, which repelled insects.

Of interest, there is a flea spray that contains cedar that really helps.

It is called EVOLV and can be found at www.wondercide.com.

Evolve can not only be safely sprayed on your pet, but can also be sprayed where they sleep, without staining the material.

  1. Flea shampoos

There are many flea shampoo products available and if you are trying a product that you have not used before, it would be best to mark with felt pen, a small circle on the skin of the abdomen of your pet, and then, apply only a small amount of the shampoo to the skin in the circle. Leave the shampoo sample there for 30 minutes and then wash it off.

If there is no inflammation of the skin with in the circle, the shampoo may not irritate your pet’s skin but it unfortunately, it may not kill fleas either.

NOTE: Over the years I have recommended the use of Head and Shoulders with Conditioner, which not only kills fleas, but gets rid of dandruff and puts lanoline back into skin and hair coat.

Because the Head and shoulders contains a conditioner, it can be used daily, but there usually is rarely a need, to do so.

  1. Check with your veterinarian and local garden supply for the safest and best chemical insect repellent to use.
  2. NOTE: often it is best to spray the yard early in the morning with the chemical insect repellant and in 1 to 2 hours, water the yard, to help force the remaining chemical deep into the roots of the grass or soil, in order to help stop any unnecessary exposure for your pet. This procedure will have to be repeated three times at a ten day, to insure that the flea eggs to do hatch, and keep infesting the yard with fleas.
  1. Chemical insecticide foggers may be used, but all foods must be placed in a safe place where no exposure can take place. Also the entire family must vacate the premise for a given period of time.
  2. Applying desiccating powders to the rugs to kill the larva and pupas. Allow the added desiccating powder to remain in the carpeting for at least two hours before removing the powder with a vacuum.

1) Borax

2) Diatomaceous earth

3) Table salt

C) Carefully placing a lighted lamp over a bowel of water at night, which contains a detergent, will cause the fleas to go to the light and drown. Please remember to place this lighted trap, where your pet cannot get to it.

D) Vacuuming can be very effective, however it is usually necessary, to place a small piece of cotton or cloth, with insecticide on it, in the vacuum bag, to stop the fleas from jumping back out of the vacuum bag.

E) Dehumidifying and air conditioning, along with vacuuming, will interrupt the flea’s life cycle.

It has been discovered, that in order for fleas to flourish, they need to live in a temperature between 70 and 90 degrees Fahrenheit.

Hopefully this article will give you a better understanding of what you should know about fleas in general, while helping you avoid the many problems they may cause, including flea allergy dermatitis.


Dr. AL Plechner