Managing Parasites in Dogs and Cats

Intestinal parasites have been around since dinosaurs and are not going away – you need to manage them. Parasites do not want to kill your pets; they want to use them as a dinner plate. They do not mind dragging pets down, causing rough hair coats, or anemia. Managing your parasites is not about deworming more or with more products. It is about using the correct dewormer at the right time to get the biggest effect for your time and money.


It helps to know the parasites we are targeting. Roundworms and hookworms live in the small intestine. The adults are easy to get rid of as most dewormers are active in the small intestine.
  • Roundworms are 3 to 7 inches long and look like spaghetti. If puppies or kittens are vomiting parasites, it is roundworms. If you have a lot of roundworms, they can be seen in the stool. Rounds are usually digested before they get through the intestinal tract.
  • Hookworms are tiny (½” long) and difficult to see without a microscope. They become a small cyst on the wall of the intestine, sitting in a protected scar tissue egg. They come out of the “scar tissue egg” when they detect pregnancy, milking, or removal of adults from the gut tube.
  • Both of these parasites can migrate through tissue, especially the liver. They get back to the intestine by migrating to the lungs where they are coughed up and swallowed. Once back in the intestine, they complete the life cycle and reproduce.
  • Parasites can play a role in the 8-week-old puppy cough.
  • Migrating stages are resistant to dewormer when outside of the intestinal tube. Once you get rid of the adults in the intestine, the larvae can pop out of the tissue and set up in the intestine you just cleared.
  • Both rounds and hooks can infect humans and must be managed before sending puppies and kittens to a new home!


Tapes and whipworms take up residence in the large intestine. They are about 30 feet down from the mouth so getting dewormer to stay active is difficult.
  • Tapes are as different from other intestinal parasites as cats are from dogs. They mostly live on dog waste and can cause colitis and irritation of the rectal area. Treatment with Praziquantel will eliminate adults.
  • Egg packets are passed and look like rice in the feces or on the rectal area. These eggs have to mature in an intermediate host (fleas, mice, or birds), and once that host is eaten by the dog or cat, they get tapeworms. If you prevent them from getting the intermediate host, you can stop tapeworms.
  • Whipworms are killed by few dewormers. Preventing re-infection is the key with whipworms that are directly infective. They will seed an exercise area down, mature, and another dog or cat will ingest them. Raised decks prevent the re-infections and break the lifecycle. New additions to a cattery or kennel need to be cleared of whipworms to prevent introduction.


Giardia and Coccidia are active throughout the intestine, but they are considered small intestinal parasites.
  • Both Coccidia and Giardia are tiny and are diarrhea-causing opportunists. Something starts the diarrhea, and they keep it going.
  • Coccidia control involves keeping the numbers so low in the kennel that you rarely need to treat. Prevention drugs are effective. Much the same is true of Giardia.
  • We try and get rid of Giardia, but it always seems to be around so prevention is the key to control.
(Read Coccidia in Dogs and Cats and Giardia in Cats and Dogs for treatment and prevention information.)


Adults are the backbone of preventing parasites. The fewer parasites mom passes to the babies, the fewer we need to manage out of our babies. Males are dewormed twice a year, and moms are dewormed before giving birth.


Parasites become active in late pregnancy when females are heavily pregnant and stressed. This is the time when moms can least resist parasites. Babies are born with sterile guts, and moms seed their guts with good bacteria to assist with digestion. However, she can also seed them with parasites. Rounds, hooks, whips, Coccidia, and Giardia can all be given to the puppy in the nursing period.

As the parasites take in the mother's nutrition, they'll also take in the dewormer - meaning we can kill them effectively. Mom may be the source of these parasites, but the parasites can be controlled. Fenbendazole is labeled for pregnant moms. It not only gets the worms, but it also kills Giardia. By cleaning up the mother in late pregnancy, you can also solve the parasite issues for your puppies later!

After 50 days gestation, deworm 3 days with Safeguard® or Panacur® C to remove as many parasites as possible from mom before birth.


No matter what the history or age, assume they have parasites! Deworm immediately, repeat in 2 weeks and start on the above adult program.

Parasites do not want to kill your pets; they want to use them as a dinner plate! Your job is to manage the parasites to prevent that from happening.

For a helpful worming guide, read Worming Schedule.

If you need help, call us at 1-800-786-4751.

-Dr. B
Don Bramlage, DVM, Director of Veterinary Services at Revival Animal Health

The materials, information and answers provided through this website are not intended to replace the medical advice or services of your personal veterinarian or other pet health care professional. Consult your own veterinarian for answers to specific medical questions, including diagnosis, treatment, therapy or medical attention.

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