Animal & Veterinary
TAKING THE BITE OUT OF FLEAS AND TICKS
FDA Veterinarian Newsletter September/October 2001 Volume XVI, No V
Fleas are truly devoted to their work. In one day, a single flea can bite your cat or dog more than 400 times. During that same day, the flea can consume more than its body weight of your pet's blood. And before it's through, a female flea can lay hundreds of eggs on your pet, ensuring that its work will be carried on by generations to come.
Flea bites may be merely a nuisance to some pets, but to others, they can be dangerous. They can cause flea allergy dermatitis—an allergic reaction to proteins in flea saliva. A pet's constant scratching to rid itself of fleas can cause permanent hair loss and other skin problems. A pet can get a tapeworm if it eats a flea that has one. And flea feasts on your pet's blood can lead to anemia and, in rare cases, death.
But fleas are not your pet's only nemesis. Tick bites can give your pet such infections as Lyme disease, ehrlichiosis, and Rocky Mountain spotted fever. And ticks can give those same infections to you.
The good news is fleas and ticks are getting easier to control. "In the last five years, flea products have greatly improved," says Ann Stohlman, V.M.D., a veterinarian at the Food and Drug Administration's Center for Veterinary Medicine. Some flea prevention treatments also help kill ticks.
In years past, veterinarians recommended getting rid of fleas by simultaneously "bombing" the house with insecticide, spraying the yard, and dipping the dog or cat, says Stohlman. Today, treating only the pet often takes care of the problem. "But if there is a severe flea infestation or if the problem persists, you may still need to treat the pet's environment," she says.
Types of Flea and Tick Products
Hundreds of pesticides, repellents, and growth inhibitors are approved or licensed to control fleas and ticks on cats and dogs or in their environment. (See "Pet Products to Control Pests"). Products range from oral medications that require a veterinarian's prescription to collars, sprays, dips, shampoos, and powders that are available at retail stores. "Spot-ons," liquid products applied directly to the pet's skin, often behind the neck, are among the latest weapons to be developed to fight fleas and ticks. Some products kill only ticks or adult fleas—others break the flea life cycle by preventing flea eggs from developing into adult fleas.
Some flea and tick products are not prescription drugs, yet are available only through veterinarians. "This is because the manufacturer chooses to sell its products through vets, so that the vet can provide important safety information to the client," says Elizabeth Luddy, D.V.M., an FDA veterinarian.
The Preventic collar is one such product. The collar kills ticks by interfering with a tick's ability to feed on dogs. It contains the insecticide amitraz, which paralyzes the tick's mouthparts. Amitraz should not be used on dogs that are sickly, pregnant, or nursing, or with certain drugs that may interact with the insecticide. The manufacturer, Virbac Corp., Fort Worth, Texas, sells the collar through veterinarians, who can ensure that a dog is healthy and can use the collar safely.
When to Treat
It's best to treat your pet at the beginning of flea and tick season, says Stohlman. The severity and length of the flea season vary depending on which part of the country you live in. "It can last four months in some places, but in other places, like Florida, fleas can live all year long," says Stohlman. Fleas also can live inside a warm house year-round.
In many areas, September is often the worst month for flea infestation. In most parts of the United States, the greatest chance of infection by a tick bite is May through September, the period of greatest tick activity by "nymphs." Nymphs are the stage of tick development that occurs after they have had their first blood meal and molt, and before they become adults.
About 200 species of ticks live in the United States. Some of these can transmit infectious diseases, such as Lyme disease, to pets and humans. Studies indicate that dogs are 50 percent more susceptible to Lyme disease than humans, according to the American Veterinary Medical Association. Lyme disease is caused by a bacterium transmitted through the bite of the deer tick, also called the black-legged tick, which is no larger than the head of a pin.
Typical symptoms of Lyme disease in dogs include joint soreness and lameness, fever, and loss of appetite. Symptoms in humans include fatigue, chills and fever, headache, muscle and joint pain, swollen lymph nodes, and a red, circular skin rash.
Some of the products shown in "Pet Products to Control Pests" can control ticks on your pet. Many other tick repellents for pets and people are available in stores.
Read the Label, Talk to Your Vet
When buying a flea or tick product, it's important for pet owners to read the label and follow the directions carefully, says Steve Hansen, D.V.M., director of the ASPCA Animal Poison Control Center. Hansen reports a "serious problem" with the misuse of dog flea and tick control products containing the insecticide permethrin. Dogs can tolerate concentrated permethrin, but "it can be lethal to cats," says Hansen. "Never use products on cats that are labeled for use on dogs only."
If the label states that the product is for animals of a certain age or older, don't use the product on pets that are younger, says Stohlman. Flea combs, which can pick up fleas, flea eggs, and ticks, may be useful on puppies and kittens that are too young for flea and tick products.
Talk to your vet about the flea and tick product most appropriate for your pet, Luddy advises. The product you use will depend on your pet's health and age, whether your pet is a cat or a dog, and whether it's an indoor or outdoor pet. Also check with your vet to determine whether the Lyme vaccine is right for your dog.
Rabbits, ferrets, and some other furry pets also can have flea and tick infestations. Reptiles, such as snakes, can get infections and anemia from tick bites. No flea or tick products are marketed specifically for use in these animals. Ask your veterinarian how to treat fleas and ticks in these and other exotic pets.
Using Flea and Tick Products Safely
- Read the label carefully before use. If you don't understand the wording, ask your veterinarian or call the manufacturer.
- Follow directions exactly. If the product is for dogs, don't use it on cats or other pets. If the label says use weekly, don't use it daily. If the product is for the house or yard, don't put it directly on your pet.
- After applying the product, wash your hands immediately with soap and water. Use protective gloves if possible.
- If your pet shows symptoms of illness after treatment, call your veterinarian. Symptoms of poisoning may include poor appetite, depression, vomiting, diarrhea, or excessive salivation.
- Store products away from food and out of children's reach.
How to Remove a Tick
If a tick is removed within 24 hours, the chances of it transmitting Lyme disease or other infections are much less. The illustrations (right) show how to remove a tick properly. Use fine-point tweezers to grasp the tick as close to the skin as possible. Pull gently. Avoid squeezing the body of the tick. Clean the site of the bite, your hands and the tweezers with disinfectant. You may want to wear protective gloves.
You also may want to place the tick in a small container, like a pill container, and bring it to your vet for identification. Never use a burned match, petroleum jelly, or nail polish to try to remove ticks. These methods are ineffective.
Pet Products to Control Pests
Hundreds of products are available to control fleas and ticks. Shown below are some of the most recently marketed products intended to treat pests on animals. If you are interested in tick control, call your veterinarian or the manufacturer to find out which kinds of ticks are found in your area and which products are effective against those ticks.
Product Administration Species Manufacturer Pests Controlled
*Program Injection Cats Novartis Animal Flea eggs
6 month injectable Health
Program Oral Dogs and cats Novartis Animal Flea eggs
Flavor Tabs Health
*Sentinel Flavor Tabs Oral Dogs Novartis Animal Flea eggs, heartworms,
(lufenuron + milbemycin Health hookworms, round-
oxime) 1-800-332-2761 worms, whipworms
Zodiac FleaTrol Flea Oral Dogs Wellmark Flea eggs
Caps (methoprene) 1-800-950-4783
Advanced Care Flea Oral Dogs Hartz Mountain Flea eggs
Control Capsules 1-800-275-1414
Capstar Oral Dogs and cats Novartis Animal Adult fleas
*Revolution Topical Dogs and cats Pfizer Animal Dogs: Adult fleas and
(selamectin) Health eggs, heartworms, ear
1-800-366-5288 mites, sarcoptic
Cats: Adult fleas and eggs, heartworms, ear mites, hookworms, roundworms
Preventic collar Topical Dogs Virbac Ticks
Advantage Topical Dogs and cats Bayer Animal Adult fleas
Kiltix (permethrin) Topical Dogs Bayer Animal Ticks
FleaTrol Power Spot Topical Dogs Wellmark Adult fleas and eggs,
(permethrin + 1-800-950-4783 ticks
Frontline Plus Topical Dogs and cats Merial Adult fleas and eggs,
(fipronil + methoprene) 1-800-660-1842 ticks
*Available by prescription only