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The idea of worms is unpleasant for many dog owners. Nobody wants to think about creepy crawlies infesting their dog’s internal organs, but understanding the risks, symptoms, and treatment options for worms in dogs is an important part of responsible dog ownership.

There are five main types of worms that commonly affect domestic dogs: roundworms, tapeworms, hookworms, whipworms, and heartworms. Here is what you need to know about worms in dogs to keep your dog safe.

Symptoms of Dogs With Worms

While each parasite affects dogs differently, there are some general warning symptoms that dog owners should be aware of. Intestinal worms may cause:

  • Diarrhea
  • Abdominal pain
  • Bloody diarrhea
  • Weight loss
  • Vomiting
  • Poor coat appearance
  • Pot belly appearance

Heartworms, on the other hand, are accompanied by respiratory symptoms like coughing, exercise intolerance, weak pulse, weight loss, and in extreme cases labored breathing, pale gums, and death.


Roundworms are some of the most common intestinal worms in dogs. There are two types of roundworms in dogs: “Toxocara canis (T canis)” and “Toxascaris leonina.” T canis is more common in puppies and can also be transmitted to humans, making it a human, as well as animal, health concern.

Many puppies are born with roundworms, which is why it is so important that your newborn puppies receive appropriate veterinary care. Roundworms are diagnosed by a fecal sample and are treated with deworming medications. If left untreated, roundworms can lead to poor growth and death in severe cases.

sad dog


Tapeworms are an intestinal parasite that dogs acquire by accidentally eating fleas or by consuming wild animals infested with tapeworms or fleas. “Dipylidium caninum” is the most common type of tapeworm found in dogs in the U.S. and is passed from fleas to dogs, giving you one more reason to take flea prevention seriously.

If your vet suspects your dog has tapeworms, he will probably ask for a fecal sample to look for eggs or segments of tapeworms in your dog’s poop. Your vet will then prescribe a treatment regimen for your dog to eliminate the tapeworms from his system.


Hookworms are intestinal parasites that cause anemia in dogs and can be fatal in puppies, if left untreated. There are several different kinds of hookworms that can affect dogs, but all feed on your dog’s blood.

Your dog can get hookworms from ingesting hookworm larvae from the environment or, in the case of “Ancylostoma caninum,” the infective larvae can pass from a bitch’s milk to her puppies. Hookworms are diagnosed by fecal floats and are treated with deworming medications.


Whipworms are a type of worm in dogs that lives in the cecum (the beginning of the large intestine) and colon, where they pass their eggs into the dog’s feces. The eggs can survive for up to five years in suitable environments (warm and moist), which is one of the reasons why cleaning up after your dog immediately is so important for general sanitation and health.

Whipworms don’t necessarily cause symptoms in mild cases, but in severe cases they can lead to inflammation, weight loss, diarrhea, and occasionally anemia. Your veterinarian can diagnose your dog for whipworms with a fecal sample and will prescribe a treatment plan suitable to your dog’s needs.

sad pug


Of all of the types of worms in dogs, the most worrisome—and the most preventable—are heartworms. Mosquitoes transmit the parasite, and since avoiding mosquitoes is nearly impossible in most places, vets recommend regular heartworm preventatives to keep your dog safe. Heartworms grow and multiply within the heart, ultimately leading to death if left untreated.

Prevention is definitely the best approach for dealing with heartworms. Treatment is lengthy, expensive, and can have serious side effects. To make matter worse, treating heartworm in dogs usually requires confinement and exercise restrictions, which is hard on dogs and owners alike.

Worms in dogs can be a serious issue, which is why it is important for dog owners to be aware of the symptoms, prevention methods, and treatment options available. Worms are not just gross, they are also a health risk, so call your vet if you suspect your dog has worms or if you want more information about worms in dogs.
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