Intestinal worms are a common health issue in dogs, affecting puppies and adults alike. These parasites can steal nutrients, cause digestive upset, and in severe cases lead to serious illness if left untreated. Luckily, available treatments are safe and easy to administer. The trick is to recognize that your dog may have worms before the infestation grows.
How Do Dogs Get Worms?
Dogs can acquire parasites in utero or via licking or eating fecal material or dirt, leaves—basically anything contaminated with parasite eggs. The eggs occur from the feces of an infected canine. Your dog can even walk through contaminated dirt and then lick his feet later, accidentally ingesting some eggs. Tapeworms require fleas or catching and eating prey such as rabbits or mice.
How Do You Know If Your Dog Has Worms?
Signs your dog has worms will vary with the type of parasite. Most parasites pass microscopic-sized eggs in the feces, but two may be visible in your dog’s stool: roundworms (ascarids) and tapeworms.
Roundworms are long, thin worms and may be seen in stool or vomited up, particularly by puppies with heavy infestations. Roundworms are usually what people are seeing when they report worms in their dog’s poop.
Tapeworms are most noticeable as egg sacks, which are called “proglottids.” These tapeworm egg sacks are small squares or rectangles that are white when fresh but can dry up into rice-like particles in both fecal material and around the hair on your dog’s rectum and tail.
If you want to see what dog worms look like, see “Worms in Dogs.”
Signs of Worms in Dogs
The clinical signs your dog has worms vary with the type of parasite and how heavy the load is. If the puppy has enough parasites, they can cause anemia and even death. A heavy parasite load may cause intussusception of the small intestinal, which is when the bowel sort of telescopes into itself. This may require emergency surgery.
With puppies, signs of worms include:
- A lack of normal growth (called “stunting”)
- Distended belly
- Crying and whimpering
- Diarrhea, possibly with blood
- Vomiting
Live adult worms, mainly roundworms, may be noted in both stool and vomit. Hookworms are particularly nasty, causing bleeding in the intestinal track which can lead to anemia. Studies document a growing resistance to treatment.
How Do You Know If Your Adult Dog Has Worms?
Intestinal parasites drain nutrients drain from your dog. This can be an issue for any dog but dogs with chronic health problems and senior dogs are at a high risk of parasite-related nutritional problems. This nutritional drain, along with the method by which the parasite gets those nutrients, leads to signs of worms in adult dogs may include:
- Weight loss or failure to gain or maintain weight
- Diarrhea or loose stool
- Vomiting
- Blood in the stool
- Anemia (usually caused by hookworms and whipworms)
- Dull hair coat
- Lethargy
There are other illnesses and conditions that can cause many of these symptoms, so unless you find a vomited worm, or worms or worm segments passed in the stool, a proper diagnosis will require a trip to the veterinarian with a fecal sample. You don’t need to bring the entire passed stool. A small chunk is adequate. The sample will be checked for microscopic eggs with fecal flotation. Alternatively, a sample may be sent out for antigen testing.
Some parasites do not shed eggs all the time or shed very few eggs. In those cases, a fecal flotation may be negative. If your dog’s clinical signs fit with an intestinal parasite, your veterinarian may recommend treatment anyway.
How to Treat Worms in Dogs
Luckily, many of the current topical treatments for fleas and ticks, as well as many heartworm preventives, have ingredients that will take care of most intestinal parasites. Tapeworms may require special medication.
Along with treating your dog, you may need to treat the environment as some parasite eggs can survive weather extremes. Also, if the infestation is secondary to fleas or hunting habits, you need to treat that primary cause if you can.





