Anyone who has ever battled fleas knows how difficult they are to eradicate. Once a home becomes infested, control can be difficult, time-consuming and expensive. A flea-infested dog or cat can introduce hundreds of new flea eggs into the home each day. By mid- to late summer, pet owners often find themselves fighting a losing battle against established flea populations that are enormous. In Southern California, where I practice, it is a year-round concern.
To effectively control fleas, it is necessary to understand their life cycle and habits. The best way to manage fleas is through prevention. By taking action before fleas are abundant, pet owners can avoid severe infestations later in the season. Preventive flea control has been made possible by new product innovations and insights into flea biology. We now know that adult fleas (the biting stage) spend virtually their entire life on the pet, not in the carpet. Eggs are laid on the fur and fall off into carpeting, beneath furniture cushions, and wherever else the pet lays, sleeps or spends time. After hatching, the eggs transform into larvae, pupae, and eventually adults to renew the cycle. Pet owners can break the cycle of flea development and prevent future generations by killing the eggs as they are laid on the pet, or by eliminating the egg-laying adults. The easiest way to do this is to take action before flea problems get out of control. Below is a quick summary of the most important aspects of the flea lifecycle.
Adult flea—lives on the host animal (dog or cat), where the female lays her eggs
Egg—flea eggs are laid on the host animal but fall off into the bedding, carpeting, and elsewhere in the animal’s environment. These pearly white eggs are barely visible to the naked eye and are usually impossible to find without a magnifying lens. Flea eggs hatch into larvae in 1–10 days, depending on the temperature and humidity; the warmer and more humid, the more rapidly the eggs hatch
Larva—flea larvae feed on organic material in the environment and on the droppings from adult fleas. They are sensitive to sunlight and to drying, so inside the house the larvae prefer deep carpet, bedding, and cracks in the floor boards. Outside the house, the larvae prefer shaded areas that have plenty of organic material (grass, leaves, etc.) or moist, sheltered soil. As the larvae feed on adult flea droppings, they are found in highest numbers in areas where flea-infested animals spend much of their time
Pupa—after 5–11 days, the larvae produce a fine cocoon in which they complete their development. During this stage of their life cycle, fleas are resistant to insecticides. In ideal conditions, adult fleas hatch from their cocoon in as little as 5 days, although fleas can survive in the pupated form for up to 5 months. Hatching is stimulated by vibration, physical pressure, heat, and carbon dioxide; in other words, the presence of a potential host animal.
Immediately after hatching from its cocoon, the adult flea seeks out a host animal. It must have a meal of blood within a few days in order to survive and produce eggs. Within 2 days of her first blood meal, the female flea begins producing eggs. Fleas can continue to produce eggs for up to 100 days. A single flea can produce thousands of eggs.
Fleas feeding on your dog can cause several problems. Most dogs will itch and scratch at the flea bite—in most dogs, the itching is mild and temporary, however, some dogs become allergic to flea saliva and develop severe itching, hair loss, and skin damage from scratching and biting at the site and the body in general. If left untreated, significant skin infections can develop. As fleas are an essential part of the tapeworm’s life cycle, dogs are commonly infested with tapeworms when they swallow fleas that contain the immature tapeworm stages. Finally, flea bite anemia can occur with severe flea infestations because of the significant blood loss associated with large numbers of fleas feeding on the host. This usually occurs only in young, sick, debilitated, or neglected animals. It is easy to tell when a dog is heavily infested with fleas, as you can see the fleas crawling over the dog’s skin and through the hair. If your dog has only a light infestation, you may not see any fleas unless you look for them. A common place to see fleas is on your dog’s belly and the inside of the thighs, where the hair is thin or the skin is bare. Another place to look is in the dense hair over your dog’s rump, especially near the base of the tail. Part the hair and inspect the skin for either fleas or flea dirt. Flea dirt is actually flea droppings. It looks like black grains of sand or cracked pepper on the dog’s skin. If you place a few particles of flea dirt on a white surface (e.g. a piece of paper) and wet them, you will see a reddish brown stain form. This is because the flea droppings contain digested blood from the flea’s blood meal. You may also notice tiny areas of dried blood on the dog’s bedding from moistened flea dirt that has since dried.
Going by the common precautionary statements on many readily available dog flea and tick treatment products, it sure seems that these products would be or could be harmful to us. So it may make you wonder what these products will do to your dog when you apply it to them. There are countless stories of dogs or cats that have suffered some ill effects from the use of these products which further add to the controversy as to whether it is indeed safe to use them on pets. That’s also precisely the reason why more dog owners are looking towards natural flea control for their dog. Unfortunately, natural remedies are universally unsuccessful in eradicating significant flea populations. They’re free of hormones and insecticides. They’re reasonably priced. They’re guaranteed. They’re safe. THEY’RE INEFFECTIVE AND A WASTE OF TIME AND MONEY. I’ve been a veterinarian for over thirty years and I’ve heard all the stories of how natural remedies such as garlic, tea tree oil, eucalyptus, fennel, rosemary, rue, wormwood, lemon grass, citronella, neem, lavender, yellow dock etc protect your dogs from fleas. I’ve dealt with numerous clients who convinced themselves that these products helped control their pet’s flea related problems and who were in total denial. I’ve seen the utilization of flea baths, flea dips, flea powder and flea collars result in toxic reactions or the death of pets because they were used without the guidance of a veterinarian’s advice. The most common mistake regarding these products is all too often the “more is better” approach that some people take when using flea products. More is NOT better when it comes to chemicals or medications! I remember going to The World’s Fair in NYC in 1964 and visiting the DuPont exhibit. Their slogan was “Better Living Through Chemistry.” Probably a bit of an over statement. Now, before you think I believe in the utilization of chemical warfare, since the availability of topical flea products such as Advantage, Frontline, Revolution, and Vectra, severe, relentless flea related problems have almost become a thing of the past.
Personally, I have not seen one animal get sick let alone die from the appropriate utilization of these products. I have, however, seen more patients die from flea infestation than from all of the above flea control products combined. Fleas cause skin disease and contribute to autoimmune disease in cats and dogs. They spread tapeworms and are vectors for infectious maladies ranging from cat scratch fever to bubonic plague.
Flea Control Recommendations
For the flea allergic patient, continuous excellent flea control is required to remain symptom free. Even very minimal exposure may be sufficient to perpetuate itching in a hypersensitive patient. In the past, veterinarians and pet owners always had to try to control fleas by treating the environment of the animal for the immature stages of the flea. This approach, although effective when properly instituted, is labor intensive and requires frequent repetitive applications. Also, some of the older products made for killing fleas on our pets do not kill fleas instantly or are not long lasting enough to really help flea allergy patients, because the female fleas survived long enough to lay a few eggs and perpetuate the life cycle.
Today’s Flea Control Products
Today, veterinarians have great flea control products that are highly efficacious, long lasting and very safe to choose from amongst. Many of these products treat more than just fleas so that there are products that can be utilized for any one of a number of situations depending upon your pet’s exposure risks. Several products are available which are convenient and effective.
Sentinel® (Lufenuron) from Novartis
These prescription drugs are available as a once a month flavored chewable (soy and pork) pill or oral liquid suspension to be given with a full meal. Female fleas that feed on pets treated with lufenuron produce sterile eggs. The product does not kill adult fleas. It is a very easy way to break the life cycle but pets remain fully susceptible to the emergence of any fleas from pupa already present in the environment. Therefore, 4 to 7 months may pass before the flea free state is reached. In order to stop the life cycle, every animal in the patient’s environment must receive lufenuron or another insect growth regulator.
This is a relatively new insect growth regulator that is extremely effective against flea eggs. It remains 100% effective for 150 days after a single spray application! It is presently available as a spray on and as a drip on in combination with permethrin for dogs and a spray with pyrethrins for cats and is included in the new product line, Vectra®. Environmental foggers and sprays are also being marketed and many professionals use this chemical for home treatments.
Advantage® (imidacloprid), K9 Advantix® (with permethrin), Advantage Multi® (with moxidectin) from Bayer
These products are available as topicals for either dogs or cats. Advantage Multi® is a prescription drug that also is a heartworm preventive. Advantage® seems to be very well tolerated by sensitive cats. It provides flea knockdown in about 8 hours. 100% killing can be maintained for at least two weeks. It is susceptible to wash off, therefore outdoor active dogs and dogs that swim or that must be bathed because of dermatitis must be re treated frequently. (Weekly re treatment is allowed with Advantage only®). Imidacloprid has no efficacy against ticks, but K-9Advantix®, with permethrin does. K9 Advantix is only labeled for once a month, and ONLY FOR DOGS.
Frontline® Spray, Frontline Plus® and Frontline Top Spot® (fipronil) from Merial
Fipronil is a broad spectrum insecticide available as a spray or a drip-on. Fipronil binds chemically to the hair and is absorbed through the hair follicle by the sebaceous glands. In spray formulation fipronil may kill fleas at 95% for up to 30 days after application on dogs and stands up to biweekly bathing. It is labeled for puppies and kittens of 8 weeks (10 weeks for Top Spot®). It is also affective against ticks. The major problem with the spray is the high volume of alcohol based product that must be applied. Many cats will show minor adverse reactions with this application technique. The product is labeled to be applied no more than once a month. Frontline Plus® contains the insect growth regulator, S-methoprene and so provides control of eggs and adult fleas.
Revolution® (selamectin) from Pfizer
This prescription drug is designed as a once-a-month heartworm preventive and flea preventive for dogs and cats as young as 6 weeks old. It also kills adult fleas and can be used to treat sarcoptic mange, ear mites and ticks. It also helps control roundworms and hookworms in cats. The product is placed on the skin at the back of the neck, but is absorbed into the body to have its effect when female fleas ingest it with a blood meal. Adult fleas will die slowly, but more importantly, female fleas stop egg production as soon as they are exposed. It is most useful as a preventive for flea infestation and in the presence of a flea problem in an allergic pet, but it is an excellent flea control product for cats.
Capstar® (nitenpyram) from Novartis
This is a prescription tablet for dogs and cats as young as 4 weeks of age. It offers extremely rapid and complete killing of adult fleas on the pets after administration. It is safe enough that the tablets may be used as needed, as often as once per day, whenever you see fleas on your pet. This is designed to be used in combination with an insect growth regulator to knock out fleas when these slower products are being used for long-term control. It can also be used when the pet has visited a flea-infested environment for rapid protection. When given every-other-day, it is a useful flea control for single cat households.
Comfortis ®for Dogs (spinosad) from Elanco Animal Health Division of Eli Lilly
This monthly prescription tablet for fleas represents a completely new class of drugs in flea control. It is available for use on puppies and dogs 14 weeks of age or older and is available in 5 different sized flavored (soy and pork) chewable tablets. It is meant to be used once a month and preliminary results show it will be very useful for flea allergic pets as it has a rapid kill rate.
Vectra 3-D for Dogs® (dinotefuran, permethrin, pyriproxifen) from Summit Vet Pharm
This product is a monthly topical application for flea, tick and mosquito control with an insect growth regulator. It provides long-lasting repellent, and is a fast acting adult flea killer that also provides control for the egg stage of the flea for at least 30 days.
Permethrin is added to provide tick control and as a repellant. Pyriproxifen (Nylar) is added for flea egg control (See above.) Water and shampooing lowers efficacy after 14 days. Do not use on cats (because of the high concentration of permethrin). This product is fast-acting and should be very useful for households with flea allergy patients.
Vectra for Cats® (dinotefuran, pyriproxifen) from Summit Vet Pharm
This product is not on market currently, but soon to be introduced.
As you can see, there are numerous products that are available to very effectively prevent and/or control your pet’s flea problem. These products differ in their ability to also control ticks, mosquitoes, heartworm disease, sarcoptic mange, ear mites, and internal parasites such as hookworms and roundworms. For these reasons, there is no one “best” product for every pet. Which one is best for you and your pet depends upon the region of the country in which you reside as this has a profound effect of your pet’s risk of exposure to these parasites. Similarly, it is important as to whether or not your pet spends significant amounts of time outdoors, goes to the dog park or doggie daycare, or is boarded frequently. In these situations, your pet is at greater risk for communicable parasitic problems. Speaking with your veterinarian and telling him or her what type of exposure risks your pet may have will enable you to decide which of these excellent products is most appropriate to not only control fleas, but to also control a variety of other parasitic issues.
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