Flea Fact and Flea Fiction


Fleas are far more than a benign and gross annoyance, and the internet is filled with an abundance of misinformation and myths. Here are a few facts and some fiction regarding fleas.

Flea facts

  • Fleas are insects. They have six legs and three body parts.
  • Of the more than 2,200 known flea species and subspecies in North America, Ctenecphalides felis (the cat flea) is by far the most common flea to hitch a ride and a meal on dogs. Cat fleas also bite cats and will bite people, too.
  • The flea life cycle is complete within two to eight weeks (depending on the environment).
  • A single flea can lay up to 50 eggs daily and 2,000 eggs in a lifetime. So, as few as two female fleas can easily produce more than 2,000 “baby” fleas, and within a few months hundreds of thousands of fleas can result.
  • A flea egg can potentially hatch in a day, though several days (up to six days) is most common.
  • Mature flea larvae in the environment produce a cocoon, which they pupate and soon develop into adult fleas. Adults emerge in about one to two weeks, when they feel the vibrations, carbon dioxide, and heat from a suitable host.
  • Pre-emerged adult fleas (in their pupae) can survive up to 210 days in the cocoon, protected from most insecticides.
  • Want to kill adult fleas fast? Lower the indoor temperature to freezing, and take all the humidity out of the room. Fleas don’t like freezing temperatures or dry conditions.
  • Newly emerged fleas can only survive 3 to 12 days without a blood meal before they starve.
  • A flea can suck more blood from a host daily than a vampire bat.
  • Most fleas in the environment are not adult fleas hopping around, and it’s the fleas you don’t see that matter. Here’s the breakdown: 57 percent are eggs, 34 percent are larvae, 8 percent are pupae, and only about 1 percent are the adult biting fleas.
  • Your average flea can jump at least a foot, which is equivalent to a person jumping about a half a block
  • Fleas are intermediate hosts of Dipylidium caninun (tapeworm). A dog or cat may swallow an infected flea while self-grooming. Once the flea is digested by the dog or cat, the larval tapeworm is able to develop into an adult tapeworm. Tapeworm is potentially zoonotic, which means people may be susceptible, though this is unusual.
  • Domestic cats are reservoirs for Bartonella henselae (bartonellosis or cat scratch disease), which they receive from infected flea bites. Humans can get cat scratch fever from a bite or scratch from an infected cat. People can also get the disease if saliva from an infected cat gets into an open wound on the body or touches the whites of the eyes. Most cats with B. henselae infection show no signs of illness, but, on rare occasions, this disease can cause inflammation of the heart, making cats sick with labored breathing. B. henselae infection may also develop in the mouth, urinary system, or eyes.
  • Fleas are also vectors of hemotropic mycoplasmosis, rickettsiosis, plague, and tularemia, all of which are zoonotic and may sicken or even kill people.
  • Why do people in high-rises with indoor-only cats sometimes get fleas? Fleas can hitch a ride on human clothing, and even on protected dogs for a short time (but long enough to drop off into the carpet) and wait until the unprotected cat passes by. A flea can even drop off a pet in a common hallway and  pass through the crack under your door.
  • In order to control fleas, a product must eliminate over 90 percent. Otherwise, the flea reproduction exceeds the ability to control.
  • According to several studies, the reasons most common for pet owners to get fleas are:
    • They don’t purchase any products to prevent fleas
    • They purchase veterinary products without proven efficacy (products without scientific data to support they work)
    • They use “homemade” remedies, of course, without any scientific data, though there may be online support on certain websites
    • They do buy appropriate veterinary products that would work well, but forget to use them or use them incorrectly or inconsistently



Flea fiction

  • Brewer’s yeast prevents fleas. “This is totally illogical,” says Kansas State University College of Veterinary Medicine veterinary parasitologist Dr. Michael Dryden. “In fact, we use brewer’s yeast in labs to grow fleas.”
  • Cedar shavings prevent fleas. The good news is that cedar has some effect on fleas; the bad news is that cedar may also have a deleterious effect on your pet’s respiratory system. In any case, while cedar shavings may kill some fleas, not enough fleas will be eliminated to make a difference.
  • Garlic prevents fleas. It seems at least some varieties of garlic may deter some fleas if rubbed all over your pet. But, who wants to live with that pet? Feeding a pet garlic may have a minimal effect. Eating too much garlic can cause garlic toxicity in a dog or a cat.
  • Penny royal oil prevents fleas. Using this member of the mint family as a dip to deter fleas may actually be dangerous for your pet, because, when licked, it may potentially affect kidney and/or liver function.
  • Avon Skin So Soft prevents fleas. “It actually does seem to deter some fleas, but not enough fleas to prevent an eventual infestation,” Dryden says.
  • Chicken soup prevents fleas. Sadly, chicken soup doesn’t work for everything.

Fact or fiction: Who knows?

  • Zombies are not affected by flea bites.