Veterinarians often hear from their clients that the flea medicine they use doesn’t seem to work any more. Maybe the fleas have become resistant to the medicine, or a new type of super flea has evolved in our area, or this year’s weather is somehow making the flea problem worse than previous years.

Practicing in Southern California for twenty-five years, I can tell you fleas are bad every single year. There is very little to no resistance to most flea products. There are no super fleas evolving and it gets hot every summer.

Then why do we get complaints from pet owners that the fleas are eating their pets alive even after giving the flea control medicines? There are four main reasons it seems this way.

First, pet owners may not be giving the medicine to all of their pets every month all year round. This is the number one reason for a stubborn flea infestation. Fleas don’t go away in the winter in Southern California. They just slow down a little. Skipping monthly treatment allows the fleas to produce eggs that eventually molt into cocoons in the environment. These cocoons wait until the weather is warm to hatch. Since each flea will produce 500 eggs, even one or two fleas per month during the winter can result in thousands of hatching fleas in June and July.

Second, the environment is not being treated. While treating the pet directly to kill the adult flea is absolutely crucial, the adult flea that lives on your pet only comprises about 5% of the entire flea population. Most of the flea life cycle is in the yard and house. Eggs, maggots and cocoons comprise 95% of the population and they are unseen for the most part. Vacuuming only gets a small percent up from carpet or cracks in wood floors. Ask your veterinarian for safe and effective products to kill the eggs and maggot stages. The cocoons, unfortunately, are nearly impossible to kill and can survive at least 350 days in almost any weather.

Third, our perception and expectation of what flea products actually do differs from reality. 25 years ago, it was not uncommon for me to have a few dogs and cats die from flea anemia blood loss every summer. The pets that died were often young puppies or kittens or ill older pets. But one case that stands out was an adult middle age healthy Dalmatian that presented for weakness and lethargy. He was about 60 pounds, covered in fleas. He collapsed and died as the owner walked him into the exam room. His body temperature was low and his gums were pale white. We took a blood sample and found his PCV, packed cell volume, was less than 10%. A normal red blood cell percent would be around 40%. (PCV is a measurement of the percent of red blood cells compared to the rest of the blood volume). All that was available to kill fleas back then was flea shampoo and sprays that contained toxic pyrethrin compounds. They would kill fleas but were short acting and could make the pets sick if used too frequently. Today we have several medicines that are extremely safe and very effective. But if the medicine is only given when you see a flea, you are missing literally thousands of cocoons that have been allowed to build up over the year that will eventually hatch and jump on your pet.

Lastly, online products may be counterfeit, outdated or were stored at too high a temperature. Several of the drug companies that produce flea control medicine only sell to authorized outlets. Many online companies do not get their supply directly from the manufacturer, but instead rely on what is known as the grey market. Grey market products do not have a pedigree or paper trail, showing who handled the product or where it came from. We are told by the manufacturers that most of the flea medicine begins to degrade if stored at temperatures above 85 degrees. So if the medicine sat in a truck in Las Vegas on its way from Florida, then there is a good chance the medicine may not work as well as intended. Always demand flea medicine be dispensed in its original packaging and that all serial numbers and expiration dates match. Call the manufacturer directly if they don’t.

Hope this helps, and as always, contact us at 562.439.4228 for the best advise on flea control for your particular situation.

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