I have seen entirely too many fleas over my 22 years in practice. I have also seen too many animals die from this entirely preventable cause. Most often, small kittens with their tiny bodies and equally tiny amount of blood. Just last month however, a beautiful, 11 year old cat was brought in, literally on the brink of death, due to blood loss and circulatory collapse from a severe flea infestation. We immediately flea treated him and, with the help of clinic cat, Rufus, gave him 50 ml of blood. He rallied to live while receiving intensive care. We did everything we could to save him. Ultimately he was too far gone and passed away three days later.
While it is mostly smaller animals, I have also seen a 70+ pound adult dog die from a severe flea infestation, merely 5 hours after arriving at the clinic before we could even get him transfused. In addition to blood loss from the parasites feeding on animals, fleas can transmit blood parasites that lead to life-threatening, hemolytic anemia, a condition caused by the immune system's reaction to the parasites and attempts to remove the compromised red blood cells from circulation.
I remember how difficult it used to be, 30 years ago, when we didn't have safe and reliable products. We had flea dips and shampoos that were sometimes safe, but were minimally effective in that they only killed what was on the animal at the time and didn't prevent future infestations. But, with the enhanced understanding of the flea life cycle and arthropod nervous system came extremely safe and effective treatments. We have had access to these products for over 20 years, yet I still see pets treated with safe but ineffective products (i.e. ALL flea collars other than Seresto) or, worse, dangerous products (i.e. pyrethrin-type pour on products). Flea control is not difficult if you know what products to use to prevent flea infestations or treat existing flea infestations (then preventing another!).
So, let's start at the beginning. How can you tell if your cat or dog (or any other mammal) is flea infested? Scratching and chewing can indicate ectoparasites as well as other skin maladies such as allergies, but if you find tiny scabs near the base of the tail and around the neck, fleas are likely the culprit. Lack of scabs does not rule out fleas, as these clinical signs occur after fleas have been present for an extended period of time, usually due to an allergic reaction. There are some telltale signs of a flea infestation - the presence of a flea or flea droppings (aka "flea dirt") give it away.
Flea dirt looks like actual dirt, or pepper, and can be seen on a table or white towel after ruffling up the fur a bit. It will also get stuck in a fine toothed flea comb. To be sure that it is flea dirt, place it on a moist, white paper towel. If it turns dark red, you've got fleas (remember they eat blood meals). Also, just one flea is significant. Cats are especially good at removing fleas from themselves by grooming and can consume dozens in just an hour (this is one of the main causes for tapeworms).
Now that you know you have fleas on your pet, you can assume that you have fleas in your house (unless the animal NEVER sets a paw inside and you have no way of carrying them in). Even with strictly indoor cats, fleas can make their way in. You will not rid the flea infestation on the animals without addressing the source of fleas. Adult fleas are only the tip of the iceberg. The VAST majority of fleas in the environment are actually in other stages of the life cycle.
Fleas reproduce by laying eggs on the host, we will call this host "Fluffy." Fluffy has the run of the house, jumps on the couches, sleeps in the bed, goes under the dining room table. Where do you think the flea eggs are? Yes indeed, Fluffy has acted as a little furry "salt shaker," shaking eggs everywhere she has traveled. These eggs will hatch and form into tiny worm-like larvae that eventually go into a sort of cocoon called pupae (plural for pupa). The adult fleas break out of pupae after they mature, but can remain in this protected state for a long time (up to 9 months!) until conditions are favorable for their survival. Things like vibrations, heat, and carbon dioxide (indicating a potential host to feed from) bring them out.
So, how to we treat 1) our pets and 2) the environment to get rid of the flea infestation? Let's start with the easy one - treating our pets. There are a plethora of flea products on the market that vary in their safety, efficacy, and cost. Being a shelter medicine veterinarian, I am very conscious of all of these factors and have treated tens of thousands of cats and dogs for fleas. We include flea treatment for every cat spayed/neutered (9,000 each year), so we want a product that is safe and effective as well as cost effective. While there are many different choices, we have used Bayer's "Advantage II" (with the active ingredient imidacloprid) for many years.
This product is applied topically to the "scruff" area of the cats and it stays just on the coat/skin without entering the bloodstream. Why do I care about this? First, I like that the product doesn't penetrate all of the body tissues. A product that stays just on the coat/skin really cannot cause any adverse reactions other than a temporary bald spot. Secondly, the fleas don't have to bite the animal to be affected. I would prefer not to get bitten by those critters and I'm sure our pets would agree.
People have asked me about products that supposedly kill fleas faster (like Capstar). I can tell you that we personally see fleas become neurologic only 30 minutes after applying the Advantage II. Neurologic fleas are on their way out. Dying. Why don't the cats also get neurologic and sick from Advantage (and Frontline, and other non-pyrethrin spot on products)? The fleas have receptors in their nervous system that mammals don't have. Imidacloprid binds to those receptors and causes spastic paralysis ONLY in arthropods such as fleas (and, as a bonus, lice).
This is what makes these products exceptionally safe. How safe? I have used Advantage on kittens with their eyes still closed (remember fleas can kill them!) up to cats in their senior years. Tens of thousands of cats over 20+ years. No adverse reactions other than a few cats with hair loss. Fleas are killed quickly and for 30 days. There is also an insect growth regulator that kills the flea eggs and larvae! Three out of the four life stages are addressed. Remember the pupae are in the environment with a whole army of replacements ready for action.
This is based on what I did when treating my mother's house years ago (she had a stray cat hanging out on her porch and her strictly indoor cats got fleas!).
- Put the pets in a room and keep them there until the carpet and other surfaces that are sprayed are dry. These products are very safe, but we don't want to expose the animals to the wet product.
- Vacuum the carpet (remember that vibrations bring out the fleas that are mature enough in pupae!). Be sure to pull out all of the furniture. You can lightly spray the Knockout under the couch and push it back while it is wet.
- Lightly spray carpets/bare floor, under furniture, under couch cushions, and everything that can't be put in the laundry. (These sprays don't require you to evacuate the room like bombs and, because you are spraying them, won't miss areas under furniture like bombs would). One can typically treats 2,000 square feet. You can apply it while standing and don't need to get down on the floor!
- After everything is dry, allow pets out of the room they were in, treat that room in the same manner, and wait until dry before letting them back in.
- Put everything that can be washed in the laundry. This includes blankets and pet beds.
- For best results, spray again in 3 weeks. This will get the remaining immature fleas that were protected in the pupae during the first spray.
- Continue applying Advantage II each month.
A note on other products - some good and others to avoid like the plague. While this is only concerning fleas, ticks are also a problem in some pets. The best product for cats, in my opinion, is the Seresto collar. The collar (the ONLY flea collar I will recommend) has Imidacloprid and ingredients that kill and repel ticks SAFELY. Frontline also kills fleas and ticks, but allows the ticks to attach. This is still a good product and would be my secondary recommendation for cats and dogs. Advantix is a safe product for dogs that will kill and repel ticks as well as fleas but WILL KILL CATS. Sorry to yell, but I've had patients die from this product even with intensive treatment.
The biggest thing to avoid in cats are pour on products with pyrethroids (pyrethrin, permethrin, etc.). This is a great example of natural not being equal to safe. Pyrethrins are derived from chrysanthemums and were some of the original (over 30 years ago) products that we had available. In a low concentration (i.e. shampoos) they probably will not harm a cat, but in the pour on products they most certainly can be deadly. The reason is that cats, unlike dogs, lack the enzyme to break down pyrethroids. It is toxic to them as it is the fleas. We just used a concentration that killed fleas but not the cat, back in the old days. There is NO REASON to use these products and they can cause twitching, seizures, and death. AVOID Hartz Bio spot and other pour ons with pyrethroids.
Also, flea collars are not likely to cause the death of the cat (unless they get hung up on them), but do absolutely nothing to kill or repel fleas (unless they are Serestos). We literally see fleas running all around them and on them. Dead fleas are not falling off the cat (as they are with Advantage). Do not use them. Beware counterfeit products also - I have seen fake Seresto collars that do not work. For those who have multi-cat households, Seresto collars are not going to be cost effective. Application of 0.5cc of Advantage II (NOT ADVANTIX) per cat once a month is the protocol we use at the rescue. It ends up being very cost effective at a couple of dollars per cat. Frontline (Fipronil) is also available in a generic form, saving money without sacrificing safety and efficacy.
Ultimately, prevention of a flea infestation is much easier than treating one. Start putting Advantage on your pets as soon as they come in to the household. Apply monthly. Keep them safe and keep your sanity!