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Many Effective Options Available for Flea Control

Many Effective Options Available for Flea Control

(June 16, 1999)

Cats and dogs don't have to suffer the itch of fleas this summer.

With a little diligence by the human companions of canines and felines and the use of innovative new pharmaceutical products, the pesky, blood-sucking insects can be controlled, according to Nancy Hinkle, an extension veterinary entomologist at the Univer sity of California, Riverside.

Flea control products used on the animals themselves have become so effective that experts are no longer emphasizing treatment of the home and yard in addition to the animal. "This is a dramatic change in flea control that has happened in the last couple of years," said Hinkle. "We finally have on-animal products that are sufficiently effective to constitute the backbone of most flea suppression programs."

Cat fleas -- the species that most commonly afflicts dogs and cats -- are a problem throughout the U.S. during the summer, particularly in regions with high humidity. Areas of Southern California, the Gulf coast, the Atlantic coast south of Maryland and Hawaii experience year-round flea problems because of relatively high humidity and temperatures, conditions conducive to flea breeding. Under ideal conditions, 100 fleas living on a dog can produce a half million offspring in a month.

And, fleas can be more than an irritation. Some flea-sensitive pets, in addition to scratching constantly, develop flea allergy dermatitis resulting in open sores that often become infected. Fleas are also intermediate hosts of tapeworms, which can enter the digestive tract when a dog or cat grooms itself.

The best time to begin the war on fleas is before pets start scratching behind their ears or nibbling their stomachs, Hinkle said.

The simplest and least invasive treatment for pets is regular grooming with a flea comb, Hinkle said. Because the tines of the comb are closely spaced, fleas can be combed out with loose fur. The combs should be used dry, with the mat of fur removed peri odically by hand and dropped into a bucket of soapy water. The soapy water will drown fleas caught in the comb.

Over-the-counter products that contain the insecticide permethrin are often more economical han products prescribed by a veterinarian, but they must be used in strict accordance to the label directions, Hinkle said. Many such products can usually be use d safely on adult dogs, but may be lethal to puppies and cats, she said.

"If cats are not explicitly mentioned on the label, do not apply the product to cats," she said. "Similarly, check to see what the minimum age for application to dogs is; often a product that is safe for adult dogs is not safe for puppies."

Pharmaceutical products marketed as Advantage and Frontline work by attacking the nervous system of adult fleas. A small amount is applied on a dog or cat's skin between the shoulder blades with each application lasting from several weeks to three months . Advantage and Frontline are available only through veterinarians.

Also available only by prescription through a veterinarian is the product Program, which contains the insect growth regulator "lufenuron" that causes a developing flea's body wall to rupture. The product - administered in pill form to dogs and by food droplets or injection for cats - has proven to be highly effective and safe for animals, according to Hinkle.

The insect growth regulator (IGR) circulates in a pet's bloodstream and is transferred to the insects when fleas bite and feed upon a pet's blood. The product also sterilizes female fleas.

Other insect growth regulators that contain methoprene are available both over the counter and through veterinarians. These IGRs coat the pet's fur so that flea eggs are exposed to the chemical, thus killing the flea embryos within the eggs. Many such pr oducts include a pyrethrin insecticide to kill adult fleas.

Flea dips that use pyrethrin chemicals are effective at knocking down a serious infestation, Hinkle said. However, the dips do not kill all of the fleas and have no lasting effect. Hinkle suggests flea dips be performed by professional pet groomers who c an properly dispose of the chemical-laden wash water.

Hinkle said pet owners should discuss flea control options with their veterinarian to determine the safest and most effective treatment.

A comprehensive attack on fleas can also include treatment of the locations in which they breed.

Indoors, frequent carpet vacuuming and laundering of pets' bedding will go a long way toward removing the eggs that fleas lay in the carpet and the eggs that fall off of pets. It takes between 24 and 48 hours for eggs to hatch, so experts recommend vacu uming carpets every other day, Hinkle said.

Flea larvae, which become entwined in fibers deep within the carpet, are sometimes difficult to remove by vacuuming alone. But professional steam cleaning twice a year - in the spring and fall - may be useful for a persistent flea problem, according to Hinkle.

Washing pets' bedding once a week using hot water and detergent will kill any flea larvae present in sleeping pads or blankets, thus preventing fleas from reaching adulthood, she said.

Powdered borate products, which go by such commercial names as Fleabusters, Doctors One and Rx for Fleas, poison flea larvae. The products typically are dusted onto carpets and brushed in so the powder can reach larvae deep within the carpet.

Hinkle cautioned that the borate products are difficult to find because there are lingering questions about potential toxicity to mammals.

Options for outdoor control of fleas are numerous.

The two most common outdoor insecticides - diazinon and Dursban - are widely available and have been proven safe and effective, she said. Animals must be removed from the yard when these granular or liquid formulations are applied and watered into the la wn. These products need to be watered into the yard because flea larvae occupy the top quarter-inch of soil, she said.

Insect growth regulators (IGRs) that contain such compounds as methoprene and pyriproxyfen can be used where eggs and larvae are often deposited, Hinkle said. Eggs can drop off pets in areas where they nap, such as doormats and under favorite trees.

The insect growth regulators work by preventing immature fleas from becoming adults, by inhibiting either their growth or development of the body wall.

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