The flea has a life cycle typical of other insects: the egg hatches into a larva, which later becomes a pupa (cocoon) and, eventually, an adult flea. Flea infestation can develop rapidly in your pet’s home: in just four weeks, a single pair of mature fleas can produce more than SIX THOUSAND eggs, larvae, and adult fleas! Most of a flea’s life cycle takes place off the pet in the house and yard. In fact, the adult fleas that you see on your pet account for only 1% of the total flea population in the home. Thus, for every flea found on your pet there are MANY, MANY more eggs and immature fleas in the carpet and yard which are less visible, yet serve as a constant source of reinfestation.
FLEA ALLERGY DERMATITIS
When a flea bites your pet for a blood meal, the flea’s saliva is secreted into the skin. If your pet is allergic to the flea’s saliva, itching may result. The chewing, scratching, and “hot spots” of flea allergy dermatitis usually occur on the hind limbs, abdomen, and rump/tail areas, but can occur on any part of the body. In cats, the neck is also commonly involved and tiny, crusty bumps can often be felt under the hair coat. The finding of fleas, flea feces (“flea dirt”), or tapeworms (which are carried by fleas) in the pet’s feces confirms the presence of flea infestation. In a very sensitive pet, the bite of a single flea can cause itching that lasts for several days; therefore, fleas will not always be easily found on a pet that is suffering from flea allergy dermatitis.
TREATMENT OF FLEA ALLERGY DERMATITIS
An animal cannot be cured of its allergy to flea bites. Cortisone drugs (tablets or injections) are effective at reducing itching and self-inflicted skin damage, but their long-term use can sometimes cause adverse side effects. Their use is best restricted to a short-term or intermittent basis, such as when flea control efforts are just getting started or during a severe itching flare up. The most important part of the treatment for flea allergy dermatitis is the elimination of fleas from the pet’s home so that exposure to flea bites does not occur. For flea control efforts to be effective, both the pets and the premises must be treated.
Scientific studies have shown that products such as garlic pills, brewer’s yeast, B-vitamins, battery-powered ultrasonic flea collars, and extracts of pennyroyal and eucalyptus are ineffective in repelling fleas from pets.
HOW TO TREAT YOUR PETS FOR FLEAS
Killing the adult fleas that are currently on your pet is helpful for both short-term and long-term flea control. The immediate removal of these fleas provides quick relief to the flea-allergic pet. Also, by killing fleas within 24 hours of their arrival on the pet (i.e., before they can lay eggs), the production of future generations of fleas in the pet’s home are prevented. Bathing your pet with a flea shampoo will kill the fleas currently present as well as remove dirt and flea feces. The oral medication nitenpyram (Capstar®) will kill fleas on your pet for about 24 hours after administration. Also, available for dogs is the oral medication spinosad (Comfortis™, Trifexis™†) which will kill fleas for a month. After bathing, the use of a residual-action product should be used to kill new fleas as they jump on your pet from the environment. Several options are available for residual treatment. The preferred residual items to use are either “spot-on” products and/or oral spinosad. Effective spot-on products currently available are:
|*Denotes that this product is also effective against ticks. |
†Denotes that this produce is also effective at preventing heartworm infection.
These products are preferred over dips because of their ease of application, quick onset of action (within 24 hours), residual effectiveness (up to or at least one full month), and safety.
HOW TO TREAT YOUR PET’S HOME FOR FLEAS
Most flea-infested homes can be successfully treated by the use of an IGR (insect growth regulator) or IDI (insect development inhibitor). These agents provide long-term flea control by either inhibiting the development of flea larvae (IGRs) or flea eggs (IDIs) in the house and yard. These products are available as an indoor premise spray, a collar worn by the pet, or as a once-a-month oral medication (e.g., lufenuron (Program™)). Also, of the topical spot-on products mentioned above, Frontline Plus® contains the IGR methoprene and Vectra 3D™, Vectra™ For Cats & Kittens, and Vectra™ For Cats contain the IGR pyriproxyfen. If your pet is severely allergic to fleas or your home has a particularly high level of flea infestation, then additional measures should be taken to treat the premises. These measures usually consist of the application of insecticides. Preparing the premises first (vacuuming and steam cleaning carpets, mopping floors, washing the pet’s bedding, raking leaves, and mowing the lawn) will improve the effectiveness of the insecticides whether applied yourself or by an exterminator. Flea larvae are found in the highest numbers in places where your pets spend most of their time (such as feeding and sleeping areas) and in dark, shaded areas (such as under bushes and furniture) because the larvae hide from light. It is very important, therefore, to spray these particular types of areas and not just fog the middle of the room and spray the open lawn. If you elect to treat the premises yourself, be sure the indoor insecticide you use also contains the IGR methoprene (Precor®). Treatment of the premises should be repeated 7 to 10 days later and then as needed. Additional measures that can be taken include physically excluding animals (pets and wildlife) from crawlspaces under homes and porches, routinely vacuuming and steam cleaning carpets, flea-catching light traps, and the outdoor use of flea larvae-eating nematode worms (Interrupt®). In most situations, the combined use of Program® with a flea adulticide (i.e., either one of the aforementioned topical spot-on products or orally-administered Comfortis™) for two to three months should be effective. In more severe infestations, the premise treatment outlined above is also required. After this initial treatment phase, preventive maintenance may consist of either just Program® orally once a month or an adulticide (Comfortis™ or a topical spot-on product) once a month. An important point to remember is that if just ONE pet in the home has fleas, then ALL pets in the home have fleas, and for any flea product to be effective, ALL pets in the home must be treated at the same time.