Controlling canine and feline gastrointestinal helminths - Veterinary Medicine
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Controlling canine and feline gastrointestinal helminths
Nearly all of our canine and feline patients, especially pups and kittens, will present with a helminth infection at some point. Some of these infections also have zoonotic potential, but fortunately most are easily treated and prevented.



Historically, efforts to control gastrointestinal helminths in dogs and cats have focused on early effective deworming of pups and kittens. At present, the joint recommendations of the Centers for Disease Control and Prevention and the American Association of Veterinary Parasitologists are that pups should be dewormed at 2, 4, 6, and 8 weeks of age with an anthelmintic effective against both ascarids and hookworms, and that kittens, which do not become infected with gastrointestinal helminths until after birth, should be dewormed at 3, 5, 7, and 9 weeks of age. Nursing dams should be dewormed along with their young. All pets should begin receiving a monthly heartworm preventive that also controls intestinal parasites at the earliest age possible (6 to 8 weeks), and they should undergo regular fecal examinations and receive treatment as needed.

Such an approach makes sense because younger animals consistently harbor larger numbers of parasites and pass more eggs in their feces to contaminate the environment. However, pups and kittens often are not brought to a veterinarian until 6 or 8 weeks of age; by that time, the environment probably has been contaminated with ascarid and hookworm eggs. To dramatically reduce infection of pups with ascarids and hookworms, dams can be treated late in pregnancy after the larvae have been activated and, thus, are susceptible to anthelmintics.22 Regardless of the approach taken, every effort should be made to ensure that all pups and kittens are cleared of gastrointestinal helminths.

In recent years, many veterinary parasitologists and internists have begun to recommend that all dogs and cats be treated for gastrointestinal parasites year-round. This approach may, at first, seem overly aggressive to veterinarians who are more comfortable with simply performing annual fecal examinations and treating any parasite infections that are detected. Annual fecal examinations followed by appropriate treatment are certainly an important part of veterinary preventive care. However, waiting for an annual fecal examination to indicate that gastrointestinal parasites are present allows the environment to become contaminated, sometimes over many months, with eggs that may then serve as a source of reinfection to that pet, other animals, and people. Treating pets routinely year-round with ant helmintics effective against gastrointestinal parasites will help eliminate patent gastrointestinal parasite infections and reduce environmental burdens of parasite stages infectious to pets and people.

Several safe effective anthelmintics are available for use in a year-round program to control gastrointestinal parasite infections in dogs and cats. Veterinarians are often comfortable with using heartworm preventives that are also effective against gastrointestinal parasites because they already use these products in their practices. In the southeastern United States, where heartworm is actively transmitted most of the year, many veterinarians already routinely prescribe year-round heartworm preventives that are also effective against intestinal parasites. The seasonality of heartworm transmission in more temperate areas depends on varying climatic factors, and the onset of mosquito activity is somewhat unpredictable. Considering how many pets travel with their owners to heartworm-endemic areas and how frequently pets encounter infectious stages of intestinal parasites in the environment, year-round administration of a heartworm preventive that also controls intestinal parasites may be warranted throughout the United States.

None of the currently available combination heartworm and intestinal parasite control products is effective against cestodes. To also eliminate infections with D. caninum and Taenia and Echinococcus species in dogs and cats, a product containing either praziquantel or epsiprantel must be used. Fenbendazole has efficacy against Taenia species but not the more frequently encountered flea tapeworm D. caninum. In addition to anthelmintics, effective control of tapeworms also requires owners to stringently adhere to a veterinarian-prescribed flea control program to eliminate reinfection with D. caninum and to prevent their pets from roaming and consuming prey to avoid reinfection with Taenia and Echinococcus species. Keeping dogs in a fenced yard or on a leash, keeping cats indoors, and feeding pets only cooked canned or dry commercial food are all excellent means of preventing parasitic infection.

Susan E. Little, DVM, PhD, DEVPC
Department of Infectious Diseases
College of Veterinary Medicine
University of Georgia
Athens, GA 30602


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