Deworming medications (antihelmintics) are used to rid pets of intestinal worms. No single dewormer removes all types of worms, but many deworming products are effective for more than one type. Generally products that are effective against round-shaped worms (rounds, hooks, and whips) are not effective against flat-shaped tapeworms.
Several heartworm medications have added ingredients that make them effective against intestinal worms as well as heartworms. Deworming medications are available as tablets, capsules, granules, chewables, liquids, and topicals.
Puppies and kittens are born with worms and should be dewormed early. Waiting until 6-8 weeks of age to worm puppies and kittens allows them to spread worm eggs that will contaminate the soil and re-infect them. The Companion Animal Parasite Council, an independent group that includes parasitologists, veterinarians, pediatricians, and representatives from the U.S. Government Centers for Disease Control made these recommendations:
Puppies: Deworm every 2 weeks from 2 weeks of age to 3 months, then deworm monthly until 6 months of age.
Kittens: Deworm every 2 weeks from 6 weeks of age to 3 months, then deworm monthly until 6 months of age.
Adopted puppies and kittens: Deworm immediately, with at least 2 more treatments at 2 week intervals.
Adult dogs and cats: Deworm every 3 months.
Pregnant bitches or queens can be dewormed through pregnancy and during whelping. This decreases the number of worms that can be passed to the young. Unfortunately, deworming medication does not kill hookworms and roundworms that remain hiding (encysted) within the mother's muscle tissues.
Puppies and kittens started on heartworm medications that contain intestinal wormers do not need to be dewormed every 2 weeks. No heartworm medications are effective against tapeworms, which puppies and kittens get from fleas. Either protect them with anti-flea medications or deworm for tapeworms every 3 months.
Ordinary fecal tests identify worm eggs. Puppies and kittens should be dewormed regardless of fecal tests because they have worms that have not matured to the point of producing eggs. The fecal tests will be negative, but the puppies and kittens are infected.
Most adults with negative fecal tests should also be dewormed because the Companion Animal Parasite Council says that about 75% of pets with negative fecal tests have worms that are found when the samples are tested at universities and parasitology laboratories.
Some round worms will mature and their eggs will pass into the feces to contaminate the environment if puppies and kittens are dewormed every 3 weeks. Deworming every 2 weeks prevents this. The Companion Animal Parasite Council calls this strategic deworming.
Homes with children, immune-compromised individuals, or elderly persons should deworm pets to prevent the possibility of zoonotic infection. Zoonotic infections are infections that occur in pets and can be transmitted to people. Roundworms and hookworms from pets cause thousands of zoonotic infections in people in the U.S. every year. These infections cause blindness, illness, and death.
Pets are dewormed for tapeworms throughout their lives. When worms live only in the pet's intestines, such as tapeworms, the pet's immune system doesn't register the tapeworm as foreign and doesn't make antibodies to attack it. Thus pets develop no protection to repeated tapeworm infections. Tapeworms are spread by fleas, and fleas can be controlled with Frontline Plus, Flea5X Plus for Dogs, Flea5X Plus for Cats, and Advantage II..
Roundworms and hookworms are different from tapeworms because they migrate through the pet's body. During their migration, rounds and hooks stimulate a pet's immune system to make antibodies to them. Thus, adult pets with mature immune systems may naturally rid themselves of roundworms and hookworms. If pets are exposed to an overwhelming number of roundworms and hookworms, or if their immune systems are not working well, they need deworming for these worms during adulthood.
Combine deworming with feces cleanup so that pets are not reinfected by worm eggs that survive in the ground. Roundworms and whipworms remain in the soil for years and are not susceptible to commonly used disinfectants, such as bleach and boric acid. However, heat above 100°F kills most worms, so that steam, boiling water, or burning straw will kill them. Immediately picking up feces dramatically reduces environmental contamination.
The Companion Animal Parasite Council developed the concept of strategic deworming, which requires deworming pets before the worms mature and produce eggs that contaminate soil. Strategic worming reduces the possibility of environmental contamination and recommends adult pets receive deworming medications every 3 months.