Dog Ticks and Cat 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, illustrated in a 794K PDF file: 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."
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. (See "Improving Safety.") 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."