Fleas: Our Ravenous Roommates --- by Lee Wetty --- Muhlenberg College Class of 2016

If I were to tell someone that most likely every day of their lives they encountered an insect whose close relative was responsible for the death of an estimated 25 million people in the 14th century, they would be shocked and rightfully terrified. That’s right! Bubonic Plague, one of the leading causes of the Black Death, which ravaged much of Europe, was spread by the bites of fleas! Don’t be alarmed however, the specific flea, the Oriental rat flea, (Xenopsylla cheopis), which was the primary carrier of the bacteria (Yersinia pestis) that caused the Bubonic plague is not commonly found in the United States. Students of Allentown’s very own Sheridan Elementary school, which recently suffered a flea infestation, know from first hand experience however that there are definitely fleas here in the United States, so let’s get to know these unwelcomed pests.

In the United States, 66.9% of households own a cat or dog. Every day, we come in contact with our pets and share our homes and even our beds with them. This puts us at a huge risk of encountering a flea infestation at some point in our life. So which species of fleas should we be concerned about?  Of the over 2000 species that have been identified across the world, the only one Americans and pet owners should be worried about is Ctenocephalides felis, better known as the Cat flea. Now you may be reading this and saying this guys a quack! I live in the U.S. and own a dog and it gets fleas. Why are we just worrying about cats getting fleas? In fact, there actually is a species of flea known as the Dog flea (Ctenocephalides canis).  However, this flea is found mostly in Europe. The Cat flea rules the U.S. and although it has a sweet tooth, or shall I say a sweet proboscis for felines, it won’t think twice before snacking on your pet dog as well. Unfortunately for us, humans are also on the menu and can serve as a quick blood meal. Fortunately, Cat fleas will never set up shop and infest us because we don’t have enough of the hairy habitat they like to call home. For the avid entomologists out there who want to examine the differences between Ctenocephalides felis and Ctenocephalides canis in their collection, Dog fleas have an anteriorly rounded head and rear tibias with eight bristle-bearing notches compared to the Cat flea, which has an elongated head, and six bristle-bearing notches.

Cat fleas, as well as all fleas, are members of the order Siphonoptera, as in “I want to siphon your blood.” (Insert vampire voice) For this task they utilize their sawing and sucking mouthparts, which enable them to consume their hosts blood. If you’ve ever had a thick milkshake, you know the struggle of attempting to suck your delicious beverage through the straw. Fleas aren’t a fan of this either so they utilize a small amount of blood-thinner that is injected with the saliva, to permit easy slurping of their meal. They are very small, about as wide as a matchstick, and light brown to mahogany in color. An innovative adaptation bestowed upon them by evolution is a lateral flattened body enabling them to weave in and out of your hairs like an Olympic skier on the slalom course. And if you’ve thought you had a clingy boyfriend or girlfriend in the past, be happy he or she weren’t a flea, since they are covered in bristles and combs that help them hang onto their hosts. Although they may appear slightly disadvantaged by their lack of wings, fleas greatly make up for this with the use of powerful hind legs that propel them through the hair and fur of their hosts, as well aid in jumping onto their next meal.

Cat fleas have also developed reproductive methods adapted to their environment. Unique in the flea world, adults remain on their host while feeding, mating, and laying eggs. In addition, larvae pupate into the adult form in silk cocoons and are stimulated to emerge by warm temperatures and mechanical vibrations, such as the activity of a pet or humans. This is why a quick search of the internet will produce many stories of people who have recently moved into a house or apartment and find its immediately infested with fleas. The adults that remained dormant were soon awakened by the activity of the new houseguests.

My family has actually had two run-ins with fleas. Once when I was a child, we had a cat that loved to spend its days in the warm attic, which soon became the dwelling place of a family of fleas. My frantic parents like many others rushed to invest in an insecticide bomb. Although it worked in removing the fleas, my mother swears that the cough I developed soon after was liked to the harsh chemicals. So, several years later, my family, now proud owners of two cats, had its second encounter with fleas. My parents always used Frontline Plus on our cats, but one spring, our defensive strategy failed. Whenever walking in the sunroom of our house with a Berber carpet (where our cats loved to lay), a storm of fleas would jump up and climb into our socks or leg hair. It got so bad that taking a lint roller and rolling it over the surface of the carpet where you stood would pick up tons of them. Now a firm opponent of insecticide bombs, my family turned toward more natural methods. We rented a carpet steamer and purchased some boric acid powder. Repeated treatments soon cleared up the mess and we were free of fleas again.

In addition to the annoyance of being bitten by fleas and having them in your home, Cat fleas pose a health risk due to their ability to transmit several diseases. As mentioned above, Rat fleas are the main carriers of plague bacteria Yersinia pestis. Although less common, cat fleas can also transfer this bacterium from infected animals to humans. In fact the United States ranks 11th in plague cases worldwide with 57 cases in the past decade. Cat fleas are also carriers of two types of rickettsia pathogens, Murine typhus (Rickettsia typhi) and Cat flea rickattsiosis (Rickettsia felis). The latter is of increasing interest due to its recent discovery. If there are any Ted Nugent fans out there you know which disease I’m going to talk about next, Cat scratch fever of course! Although Ted wasn’t referring to the disease caused by the bacterium Bartonella henselae, rather he was using the 1970’s street slang for the disease Syphilis. Cat scratch fever is a real illness that can be transmitted from infected flea droppings to humans after a scratch or bite is inflicted. Fleas have also can carry a tapeworm known as Dipylidium caninum, which may be transmitted to humans when an immature flea containing the parasite is swallowed. The best way to protect yourself and home is to engage in proper methods to combat fleas on our pets and in our homes.

Now that you know all about fleas, you probably want to know the best way to keep them out of your life, and in the unfortunate event that you have fallen victim to an infestation of fleas, how to reclaim your homestead. First lets talk defense. The best way to combat the introduction of fleas to your home is to vacuum regularly. Recent research shows that vacuuming actually kills fleas in all stages of their lives. Also make sure to regularly clean pet bedding. Keep your yard clear of leaves and long grass where larvae can avoid light and survive outdoors. There is even an invertebrate ally you can use as a weapon against fleas in your yard! The nematode Heterorhabditis bacteriophora can per purchased at many garden stores and sprayed onto a lawn to help combat the chance of fleas spreading outside your home.

Now if you do find your home overrun by fleas, the first things most of you will do is go out and buy as many chemical foggers “bug bombs” as possible. Now PAUSE! And REWIND! I highly recommend against this tactic! Bug bombs contain powerful and potentially dangerous pesticides and if not implemented correctly can live up to their name and actually explode. The EPA has an entire webpage dedicated to safety precautions when using foggers. A much safer and most likely more effective and long lasting approach is to employ the use of diatomaceous earth and boric acid. Diatomaceous earth (food grade) and Boric Acid both work by damaging their exoskeleton causing them to dry out. I do recommend that you try these methods first but if your fleas still persist turn it over to a professional exterminator who is trained in using heavier weaponry.

In addition to protecting your home, may pet owners including my family for many years have turned to chemical flea and tick products that are applied directly to the animal. Although widely used and approved by the EPA, studies show that they may have adverse and potentially harmful effects on both the pets and owners. It is up to you to interpret the studies and decide what is best for your pets. There are also many natural remedies available that attempt to provide the same protection from fleas without the strong chemicals.

Hopefully with this new knowledge of fleas and their environments you can better understand your enemy and carry out a successful plan of attack.

Fleas: Our Ravenous Roommates by Lee Wetty is licensed under a Creative Commons Attribution 4.0 International License.