by Dixie Farley

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

Mary scratches her 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 given by her owners at the beach, the house unfortunately is not.

During the weeks before Mary’s vacation, fleas feeding and breeding on Mary’s pets deposited unborn offspring all over. 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.

Common household fleas don't usually transmit diseases to pets and people. The tiny insects are mainly "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 liquid one-spot topical treatments.

AMERICAN FLEAS
While there are more than 200 species of fleas in the U.S., 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 a warm breeding ground.

The flea life cycle has four stages: egg, larva, pupa, and adult. Female fleas lay as many as 50 eggs a day, starting a life cycle that can be completed in as little as three weeks. 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 "hibernating" can extend the flea life cycle and 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, beginning the cycle all over again.

FLEA BITE ILLNESSES AND SYMPTOMS
• Anemia: May appear in sickly, old or young pets. Symptoms are pale gums, weakness and lethargy.

• Tapeworms: A flea can sometimes transmit tapeworms to your pet. Symptoms of a pet with tapeworms may include irritability, erratic appetite, a shaggy or mottled coat, mild diarrhea, sudden weight loss or seizures.

• Plague: Rodent fleas have been known to transmit the plague to cats. Though this is rare, it is possible. Symptoms may include fever, swollen lymph nodes, mouth sores, swollen tongue, coughing and pneumonia.

Keep in mind also that some pets are extremely allergic to flea bites. In these pets, fleas may cause a rash, inflammation, and/or hair loss. In response, cats may compulsively groom themselves more than normal.

Washing your pet's bedding regularly and vacuuming frequently may help to 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.

TICKS
A tick has harpoon-like barbs in its mouth that attach to a host for feeding. Crablike legs and a sticky secretion help hold the tick to its host. When attempting to remove a tick, 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. Egg, larva, nymph, and adult. 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, this happens more than once. Finally 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 to feed on blood 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.

TICK RELATED ILLNESSES AND SYMPTOMS
• Babesiosis: lethargy, appetite loss, weakness, pale gums

• Ehrlichiosis: high fever, aching muscles

• Lyme disease: lameness, swollen joints, fever, poor appetite, fatigue, and vomiting (it is possible however for infected animals show no symptoms)

• Tick paralysis: (Occurs only with dogs) gradual paralysis, seen first as an unsteady gait from uncoordinated back legs (not all dogs develop paralysis).
In 1992, the USDA licensed a vaccine to prevent Lyme disease in dogs (there is no vaccine for cats).

According to the 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."

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 the 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. Also, some products should not be used together or in conjunction with other medicines.

With cats, use only products labeled for cats. Cats are generally more sensitive than dogs. Dogs groom, but cats groom more, so they would ingest more of a topical product. They are also smaller in size which may make them react differently to a medication just as a human child would be more severely affected by a medication than an adult.

Hundreds of pesticides and repellents are approved or licensed to control fleas and ticks on cats and dogs or in their environment. To select the proper product for your pet's individual needs, talk to your veterinarian, says Larkins. "It's a personal choice between you and your vet about the best product to use and how to treat the animal, as well as the environment."

USE OF FLEA AND TICK PRODUCTS
• Read the entire label before use and follow directions exactly. If you don't understand something, ask your veterinarian.
• If you are treating a cat, use only products that are specifically labeled for cats. Products for dogs or other animals may not help or in some cases make your cat ill.
• Store any products away from food and out of the reach of children.

PREVENTING TICK-BORNE DISEASES
If your dog is outside regularly, ask the veterinarian about the Lyme disease vaccine. (There is no vaccine for cats.) Watch for itching, pain, appetite loss, lethargy, fever, swollen joints, or lameness. If you suspect a tick-borne disease, see the veterinarian immediately. With early diagnosis, antibiotics generally work.

The Lyme Disease Foundation, suggests:
• Apply tick-killing pesticides to your pets.
• Treat your pet's environment with tick-killing pesticides.
• Mow grass regularly.
• If possible, avoid allowing your pet in grassy, wooded or beach areas, unless you take appropriate precautions. While in areas of tick exposure, examine your pet closely for ticks on a daily basis, especially around the head and inside the ears.
• Remove ticks immediately. This is important because it can take hours for an infected tick to transmit disease. Using fine-point tweezers, grasp the tick where the mouth parts are embedded in the skin and pull gently. Make sure you've cleaned your hands, the bite site, and the tweezers with disinfectant.
• Place the tick in a small container, like a pill vial. Label the container with the date, your pet's name, the type of animal, and your name, address, and phone number. Call your veterinarian about having the tick analyzed for type and possible diseases it may transmit.
• Never remove a tick with your fingers, as the squeezing may further inject infectious material.
• Never try to burn a tick off or to smother it with petroleum jelly or nail polish. These methods are ineffective and may injure your pet.

In addition, you can take these steps to help protect yourself when in wooded areas and grasslands:
• Wear long-sleeved shirts tight at the wrists, long pants tight at the ankles and tucked in socks, and shoes covering the whole foot.
• Wear light-colored clothes that show ticks easily.
• On clothing, use a repellent containing permethrin. Do not apply it to clothing while it is being worn, and allow the clothing to thoroughly dry before wearing.
• On skin, use a repellent containing DEET. But don't overdo it. Too much bug spray can cause breathing difficulty, especially in children.

HUMAN PROBLEMS ASSOCIATED WITH FLEAS AND TICKS
Lyme disease is by far the most often reported tick-borne disease in humans in the United States, with 23,000 reported cases in 2002. Symptoms include fatigue, chills and fever, headache, muscle and joint pain, swollen lymph nodes, and a red, circular skin rash.

The next most prevalent disease from ticks is Rocky Mountain spotted fever, characterized by fever, headache, rash, and nausea or vomiting. It affects more than 500 people each year, according to the national Centers for Disease Control and Prevention.

CDC received reports of 415 cases of human monocytotropic ehrlichiosis, a disease also transmitted by ticks, since it was identified in 1986. It is similar to Rocky Mountain spotted fever, but usually without the rash. In 1994, scientists identified another similar disease, human granulocytic ehrlichiosis, or HGE. About 170 cases have been reported.

The organism that causes the tick-borne disease babesiosis infects red blood cells, which burst and die, resulting in hemolytic anemia. Patients develop a malaria-like fever, chills, sweats, muscle aches, nausea, and vomiting; those with no spleen are at particular risk of developing severe disease. The reported incidence of babesiosis is about one-tenth that of Lyme disease, or even less, according to Sam Telford, Ph.D., a lecturer on tropical public health with the Harvard School of Public Health.

Lyme disease, HGE, and babesiosis are all transmitted by the deer tick. Ticks have been found to have any two of those disease-causing organisms. "I believe it's only a matter of time before we find a tick with all three," Telford says. The lone star tick transmits human monocytotropic ehrlichiosis.

Many exposed people never develop the diseases. Roughly 5 percent of the coastal Massachusetts' population has antibodies against babesiosis, Telford says. "We believe it's about the same for ehrlichiosis. For Lyme disease, it's maybe three times that."

Fleas or an infected animal can transmit bubonic plague. Seven cases, including one death, were reported to CDC in 1995, in Arizona, California, New Mexico, and Oregon. Another 13 cases, also including one death, were reported in 1994, in Arizona, California, Colorado, New Mexico, and Utah.

Early diagnosis and treatment give humans the best chance of recovery from these and other flea- or tick-transmitted diseases.

This article has been modified from it's original version to include updated statistics, spelling corrections and for the rewording of some items. The original version can be found here at the FDA's website:

http://www.fda.gov/fdac/features/696_flea.html

Dixie Farley is a staff writer for FDA Consumer.