Shih Tzu - Fighting Fleas and Ticks

Back from vacationing at the beach, Fido and Kitty sniff out familiar haunts around the yard. Meanwhile, their owner, Mary, plops down on the family room carpet with a month's mail.

Mary scratches an ankle, then the other one, then a leg. Then she looks down and sees why she's scratching: Fleas!

Although Fido and Kitty are flea-free after dog and cat pesticide dips at the beach, the house is not. During the weeks before vacation, fleas feeding and breeding on the pets deposited unborn offspring all over the homestead. And during the vacation, fleas at various life stages evolved, nourished by dried-blood flea excrement, "flea dirt," in the carpet and elsewhere. The result: A population explosion of fleas ravenous for fresh blood.

The scenario is fictional. But it depicts this fact: Left uncontrolled, bloodsucking pests can infest not just your cat or dog, but your entire house--and you!

Common household fleas don't usually transmit diseases to pets and people. The tiny insects are mainly "just a nuisance," says Marcia Larkins, D.V.M., chief of the companion and wildlife drugs branch in the Food and Drug Administration's Center for Veterinary Medicine. "They generally cause a lot of itching and scratching. They may also cause some discomfort due to possible allergic flea bite dermatitis."

Ticks, those other dreaded bloodsuckers, pose greater risk, annually giving pets and thousands of people illnesses such as Lyme disease.

Fortunately, a wide array of pest control products for pets are available: foggers, sprays, dips, powders, dusts, collars, oral liquids and tablets, and even a liquid one-spot topical treatment. There are new oral products that interrupt the flea's life cycle, a Lyme disease vaccine for dogs, and a pesticide product that mimics mouse nesting material to reduce ticks outdoors.

FDA shares regulation of these products with the Environmental Protection Agency and the U.S. Department of Agriculture. If a pest-control product for pets is given by mouth, injected, or absorbed through the skin, FDA regulates it. Otherwise, EPA does. USDA licenses products that treat or prevent animal illness caused by pests. States sometimes add licensing requirements.

American Fleas

While there are more than 200 species of fleas in this country, the main troublemaker for pets is the cat flea. Happy to feed on anyone in the household--cat, dog or human--these wingless insects will most likely choose a pet, whose fur provides warm camouflage for their breeding ground.

The flea life cycle, illustrated in a has four stages: eggs, larvae, pupae, and adults. Female fleas lay as many as 50 eggs a day, starting a life cycle that can be completed in as little as three weeks, depending on temperature and humidity. The eggs hatch into larvae, which feed on "flea dirt," excrement of partially digested blood. Larvae grow and molt twice, then spin cocoons, where they grow to pupae and then adults. The adult remains in the cocoon until vibrations indicate a host is nearby. This waiting can extend the life cycle. It also explains why large numbers of fleas often are seen when an empty building is reoccupied. Six-legged adults emerge and attach to a host to feed and breed, beginnning the cycle all over again.

Even when fleas elude detection on a pet, their black poppyseed-like excrement gives them away.

The main problem with fleas--itching--is due not only to their bites, but also to their crawling over the skin.

Other flea bite problems and their symptoms include: anemia in young, older or ill pets--pale gums, weakness, lethargy transmission of tapeworm to pets--irritability, erratic appetite, shaggy coat, mild diarrhea, weight loss, seizures transmission by rodent fleas of plague to cats--fever, swollen lymph nodes, mouth sores, swollen tongue, cough, pneumonia.

Also, some pets are extremely allergic to flea bites. In these pets, fleas may cause a rash, inflammation, and hair loss. In response, cats may compulsively over groom.

Preparations made from antigens extracted from fleas may help, says David Espeseth, D.V.M., deputy director of USDA's Division of Veterinary Biologics. USDA has licensed several.

"If a pet shows a reaction in a skin test," Espeseth says, "that antigen may be effective in treating the animal against that sensitivity. When allergic animals don't react in the skin, this may mean you don't have the right antigen."

FDA has approved new types of prescription flea-control products:

Proban (cythioate), first oral insecticide for dogs--A liquid or tablet, Proban is given once every three days or twice a week. Several weeks' treatment may be needed if fleas reinfest the dog.

Pro-Spot (fenthion), first topically absorbed insecticide for dogs--A liquid, Pro-Spot is applied to one spot between the dog's shoulder blades no more than once every two weeks. Treatment length depends on the rate of flea infestation.

Program (lufenuron), first oral insect growth regulator (IGR) for dogs--A tablet, Program is given once a month with a full meal. The IGR interrupts the flea life cycle: Upon biting the pet, the female flea ingests the IGR, which deposits in her eggs to stop them from developing.

Program (lufenuron suspension), first oral IGR for cats--A liquid, Program is given once a month, mixed with food. Cats must be at least 6 weeks old.

Washing the pet's bedding regularly and vacuuming frequently also helps keep the flea population down. The vacuum bag should be changed after vacuuming and the used one burned, if possible, to prevent it from serving as a flea incubator. Cats who don't go outside have the least risk of getting fleas.

Tenacious Ticks

A tick has a one-piece body. The harpoon-like barbs of its mouth attach to a host for feeding. Crablike legs and a sticky secretion help hold the tick to the host. When attempting to remove a tick, to prevent the mouth part from coming off and remaining embedded in the skin, grasp the mouth close to the skin with tweezers and pull gently.

Ticks are not insects like fleas, but arachnids like mites, spiders and scorpions. They have a four-stage life cycle, eggs, larvae, nymphs, and adults. Adult females of some species lay about 100 eggs at a time. Others lay 3,000 to 6,000 eggs per batch. Six-legged larvae hatch from the eggs. After at least one blood meal, the larvae molt into eight-legged nymphs--in some species, more than once. Final nymphs molt into adult males or females, also with eight legs. Depending on its species, a tick may take less than a year or up to several years to go through its four-stage life cycle. While ticks need a blood meal at each stage after hatching, some species can survive years without feeding. The United States has about 200 tick species. Habitats include woods, beach grass, lawns, forests, and even urban areas.

Ticks may carry various infectious organisms that can transmit diseases to cats and dogs, including the following (listed with possible symptoms):

babesiosis--lethargy, appetite loss, weakness, pale gums

ehrlichiosis--high fever, muscle aches

Lyme disease--lameness, swollen joints, fever, poor appetite, fatigue, and vomiting (some infected animals show no symptoms) tick paralysis in dogs--gradual paralysis, seen first as an unsteady gait from uncoordinated back legs (some infected dogs don't develop paralysis).

In June 1992, USDA licensed a vaccine to prevent Lyme disease in dogs. This followed a conditional license in 1990.

According to USDA's Espeseth, "There were early concerns about disease related to abnormal immune responses. But we've never seen this. Nor have we seen such responses with extensive safety testing prior to the final licensing."

In most cases, immunity lasts at least five or six months, Espeseth says. "The recommendations are for dogs actively in the field, subject to exposure. For dogs in apartments or those that very seldom get out or reside in regions where Lyme disease isn't prevalent, it's probably not worthwhile."

To reduce the population of deer ticks, which transmit Lyme and other diseases and often attach to the deer mouse, EPA has licensed a product named Damminix. It consists of tubes stuffed with cotton balls treated with the pesticide permethrin.

"The cotton balls mimic the nesting material for the deer mouse," says George La Rocca, a product manager in EPA's Office of Pesticide Programs. The label, he says, directs users to place the tubes containing the cotton balls in outdoor areas inhabited by mice, such as brush-covered and wooded areas. "It kills and repels ticks on the mice. It's not meant to eradicate Lyme disease, but to reduce its incidence."

Debugging

To protect pets from the discomfort and illness caused by fleas and ticks, it's important to rid the pets of the pests. It's also important to treat a pet's environment to prevent or reduce the incidence of reinfestation, says FDA's Larkins.

Products to control these pests are not risk-free, however. Approved or registered products must warn users about the risks the product poses and give directions for safest use. Proban's label, for example, warns that the product is not for use in greyhounds, who are sensitive to the insecticide it contains, an organic phosphate. Also, some products should not be used together or when a pet is taking certain medicines.

Larkins advises, "Follow directions for use very carefully, even with over-the-counter products. If you don't understand the directions or have questions, talk to your veterinarian."

EPA product manager Rick Keigwin agrees. As pesticides are intended to kill pests, they generally are inherently toxic, he says. "Some products pose some risks, but they also offer significant benefits. We balance the risks with the benefits."

La Rocca adds that with cats, use only products labeled for cats. "Cats are more sensitive than dogs in general," he says. "It also has to do with their size--just like children are more sensitive than adults--and their grooming habits. Dogs groom, but cats groom more, so they would ingest more of a topical product." Virtually hundreds of pesticides and repellents are approved or licensed to control fleas and ticks on cats and dogs or in their environment.

To select proper products for your pet's individual needs, talk to your veterinarian, says Larkins. "It's a personal choice between you and your veterinarian about the best product to use and how to treat the animal, as well as the environment."

Improving Safety

Pesticides and repellents to protect cats and dogs from fleas and ticks have risks as well as benefits. Concerned over recent reports of adverse effects from such products, the Environmental Protection Agency, in cooperation with industry, has developed guidance for labeling changes to promote proper use.

The effort, coordinated by EPA policy analyst Janet Whitehurst, began early in 1994, when she learned that in just 18 months, EPA had received 853 reports of adverse effects, including 148 animal deaths and 58 reports of illness in humans. Most reports involved cats, which are more sensitive than dogs.

Improved labels would:

Direct users to read the entire label before each use.

Clearly state the animal for which the product is registered and the minimum age for safe use.

Caution users to consult a veterinarian before treating certain animals, such as those that are ill or pregnant (unless safety is known).

Warn about adverse reactions and interactions with medicines or other chemicals.

Advise users to wash their hands after use.

Clearly state limitations for reapplication.

Give a phone number to call about proper use and emergencies.

Include first-aid information.

Using Flea and Tick Products

Read the entire label before use. If you don't understand something, ask your veterinarian.

Follow directions exactly, using latex gloves if possible. Then wash your hands.

On cats, use only products labeled for cats.

Store products away from food and out of children's reach.