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Flea Control for Cats



Overview
Diagnosis of Flea Infestation
The Flea's Life Cycle
Flea Control
Newer Products
Environmental Control
Re-emergence of Fleas

Overview
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Successful flea control has two aspects. Fleas must be controlled on your cat, and fleas must be controlled in your cat's environment. Since cats and dogs share the same fleas, the presence of a dog in your cat's environment can make flea control much more difficult.

Diagnosis of Flea Infestation
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When a cat is heavily infested with fleas, it is easy to find them. If the numbers are small, it is best to quickly turn your cat over and look on his or her belly. If you do not find them there, look on the back just in front of the tail (tailbone or 'rump' area). Be sure to part the hair and look at the level of the skin. When the number of fleas is very small, look for "flea dirt." Flea dirt is digested blood left behind by the fleas. Flea dirt is actually fecal matter from the flea. Finding flea dirt is a sure indication that fleas are present or have been present recently.

Flea dirt looks like pepper. It varies from tiny black dots to tubular structures about 1/32? (1/2 mm) long. If you are in doubt of its identification, put the suspected material on a light colored tabletop or counter top. Add one or two drops of water, and wait about 30 seconds. If it is flea dirt, the water will turn reddish brown as the blood residue goes into solution. Another trick is to put some of the material on a white paper towel and then wet the paper towel with water. A red stain will become apparent if you gently wipe the material across the surface of the paper towel.

The Flea's Life Cycle
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To appreciate the complex issue of flea control, it is helpful to have an understanding about the flea's life cycle.

Although the human eye is generally able to see the adult flea, there are actually 4 stages of the life cycle. The adult flea constitutes only about 5% of the entire flea population if you take into account all four stages of the life cycle. Flea eggs are pearly white and about 1/32? (1/2 mm) in length. They are too small to see without magnification. Fleas lay their eggs on the cat, but the eggs do not stick to the cat's hair. Instead, they fall off into the cat's environment. The eggs make up 50% of the flea population. They hatch into larvae in 1 to 10 days, depending on temperature and humidity. High humidity and temperature favor rapid hatching.

Flea larvae are slender and about 1/8 - 1/4? (2 to 5 mm) in length. They feed on organic debris found in their environment and on adult flea feces, which is essential for successful development. They avoid direct sunlight and actively move deep into carpet fibers or under organic debris (grass, branches, leaves, or soil.) They live for 5 to 11 days before becoming a pupa.

Moisture is essential for their survival; flea larvae are killed by drying. Therefore, it is unlikely that they survive outdoors in shade-free areas. Outdoor larval development occurs only where the ground is shaded and moist and where flea-infested pets spend a significant amount of time. This allows flea feces to be deposited in the environment. In an indoor environment, larvae survive best in the protected environment of carpet or in cracks between hardwood floors. They also thrive in humid climates.

Following complete development, the mature larvae produce a silk-like cocoon in which the next step of development, the pupa, resides. The cocoon is sticky, so it quickly becomes coated with debris from the environment. This serves to camouflage it. In warm, humid conditions, pupae become adult fleas in 5-10 days. However, the adults do not emerge from the cocoon unless stimulated by physical pressure, carbon dioxide, or heat.

Pre-emerged adult fleas can survive up to 140 days within the cocoon. During this time, they are resistant to insecticides applied to their environment. Because of this, adult fleas may continue to emerge into the environment for up to 3 weeks following insecticide application.

When the adult flea emerges from its cocoon, it immediately seeks a host because it must have a blood meal within a few days to survive. It is attracted to people and pets by body heat, movement, and exhaled carbon dioxide. It seeks light, which means that it migrates to the surface of the carpet so that it can encounter a passing host. Following the first blood meal, female fleas begin egg production within 36 to 48 hours. Egg production can continue for as long as 100 days, which means that a single flea can produce thousands of eggs.

This entire life cycle (adult flea -> egg -> larvae -> pupa -> adult) can be completed in 14-28 days with the proper temperature and humidity conditions. This adds to the problem of flea control.

If untreated, the female flea will continue to take blood for several weeks. During that time, she will consume about 15 times her body weight in blood. Although the male fleas do not take as much blood, they, too, contribute to significant blood loss. This can lead to the cat having an insufficient number of red blood cells, which is known as anemia. In young or debilitated cats, the anemia may be severe enough to cause death.

Contrary to popular belief, most cats have rather limited itching due to fleabites. However, some cats become allergic to the saliva in the flea's mouth. When these cats are bitten, intense itching occurs, causing the cat to scratch and chew on its skin.

Flea Control
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Successful flea control must rid the cat of fleas and it must rid the cat's environment of fleas. In fact, environmental control is as important as treatment of the cat. If your cat remains indoors and you do not have other pets that come in from the outside, environmental control is relatively easy, especially with the advent of the new topical products (see below). However, the cat that goes outdoors or stays outdoors presents a somewhat greater challenge and a few fleas may occasionally be seen indoors.

Elimination of fleas from your cat's environment is important for many reasons. Fleas can cause intense itchiness in some cats, and anemia in others. Fleas also are carriers for tapeworms, as well as a number of other bacteria and blood parasites, all of which can result in health problems for the affected cat. In addition, fleas are important in the transmission of a number of diseases to people, including Bartonella (cat scratch fever), plague, etc.

Many of the older insecticides (which had been the mainstay of flea control for years) have limited effectiveness against fleas because they are only effective for a few hours after application on the cat. Also, these are primarily geared to kill adult fleas. Flea powders, sprays, and shampoos will kill the fleas present on your cat at the time of application. However, most of these products have little or no residual effects, so the fleas that return to your cat from his environment are not affected. Thus, your cat may be covered with fleas within a day after having a flea bath or being sprayed or powdered.

However, more effective products (oral, topical, and collar) are now available.

Flea Products
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Topical treatments that are applied to the nape of the neck. These include Revolution*, Frontline Top Spot*, Advantage* and others. All are safe and very effective. They are effective for about a month after application.

Capstar* is a pill that is given by mouth and will cause all the fleas on the cat to die with in about 6 hours. It is usually combined with one of the above products to eliminate fleas and prevent reinfestation.

Please be aware that all "spot-on" treatments are not the same! Spot-on treatments purchased at pet supply or grocery stores may contain a completely different medication as compared to the medications in the products available through veterinarians. In general, these over-the-counter spot on treatments are less effective (may only kill 40-60% of the fleas), last for shorter amounts of time (usually about a week), and can be more toxic, especially to cats. Never apply a canine spot-on treatment to a cat.

Also beware when purchasing flea products from an online store that you first validate that that store is a reliable source of quality product. (Unfortunately, some online pharmacies have been found to be fronts for businesses breaking federal, state and even international laws).  Visit the following sites regarding internet pharmacies for assistance in this area:

www.fda.gov/AnimalVeterinary/resourcesforyou/animalhealthliteracy/ucm203000.htm

www.fda.gov/ForConsumers/ConsumerUpdates/ucm227350.htm

www.nabp.net/programs/accreditation/vet-vipps/

Environmental Control
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The newer topical products do not require the aggressive environmental control that is necessary if only dips, sprays, or collars are used. This is one reason that they have become so popular with pet owners. Please consult with us about the requirements for your specific situation.

When environmental flea control is indicated, it must be directed at your house and your yard.

House: Vacuuming can be a very effective tool. Vacuuming can initially pick up flea eggs, larvae, and adults. The pupae, however, cannot simply be vacuumed up because they are tightly adhered to the carpet fibers via their cocoons. To remedy this, we recommend vacuuming once, wait an hour and vacuum again. Pupae will come out of their cocoons because of the vibration caused by the first vacuuming and can then be sucked up in the second vacuuming. Always empty the canister or throw out the bag after vacuuming.

We also recommend thorough vacuuming/cleaning of all hardwood or tile floors (fleas and their eggs can "hide out"along the grout or crevices in these floors). We also recommend using vacuum attachments along all baseboards in the home, as well as on sofas, chairs, carpeted cat trees, etc. (Use the attachments underneath the cushions on the sofa, too). Any bedding (pet, human) should be laundered in hot water. If these aggressive home management measures are done every couple of weeks for 2-3 cycles, and all cat and dogs in the home have been treated appropriately, often no further in-home flea control (such as the use of pesticides, which many of us prefer to avoid) is necessary. This is especially true in the population of cats that we see at Cat Hospital of Chicago, the majority of whom spend little, if any, time outside, in whom flea prevention is appropriately practiced, and who live in a city that experiences cold winters (fleas can't survive outside when the temperature falls below freezing).

In situations where the flea problem is especially severe, however, you can use room sprays or foggers or a professional exterminator may be called to treat your house. These foggers and sprays are very effective for adult fleas, but they will not kill adults that are still in their cocoon. Sprays may work better because they can be directed under furniture and into other flea-infested areas, whereas foggers will miss some of these areas, treating tabletops and other areas that are less of a problem. You should purchase a fogger or a spray that kills the adult fleas and inhibits development of the eggs and larvae. In climates with extended warm temperatures and high humidity, it may be necessary to treat two or three times with a thirty-day residual product before all stages of the fleas are removed from the house. The second treatment is most effective if it is done 2-4 weeks after the first.

Yard: A professional exterminator may also do yard control with various insecticides or you may use some yourself. Be sure that any insecticide that you use has a thirty-day residual. This keeps you from having to spray every week. In climates with extended warm temperatures and high humidity, it will often be necessary to treat monthly during the warm months of the year. You should use a thirty-day residual product each time. Your veterinarian is able to help you choose the most effective product for your situation.

Re-emergence of Fleas
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As mention previously, pre-emerged adult fleas can survive up to 140 days within the cocoon. This is significant when your pets are gone from home for extended periods of time. During the time that the house is quiet and empty, pre-emerged adults remain in their cocoon. Even if the house was treated with an insecticide, their cocoon protects them. When people and pets return to the house, adults emerge from their cocoons and immediately begin to seek a blood meal. They jump on cats, dogs, and even people. Although it may appear that a cat just returned from boarding brought fleas to your home, it is also very possible that a sudden emergence of adult fleas may account for the fleas present. If large numbers of fleas are seen, they are almost certainly newly hatched fleas and have not been brought home with the pet.



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