Symptoms of worms in dogs include coughing, vomiting, diarrhea, loss of energy, a pot belly, a change in appetite, a loss of weight, a dull coat or itching. There are also cases where a pet owner can actually observe worms in the dog's coat or fecal matter. If a worm appears in the fecal matter or vomit, the owner should preserve a sample to show to a veterinarian.
There are five types of worms that affect dogs: heartworms, roundworms, hookworms, tapeworms and whipworms. Heartworms and whipworms are generally the hardest to diagnose because they do not appear in fecal matter or vomit. Tapeworms can be identified relatively easily as segments of the worm can be found in a dog's fecal matter, and the animal generally experiences rapid weight loss due to the worm stealing the dog's nourishment in its intestinal track. A dog may have hookworms if blood appears in its stool. The bleeding is caused when the hookworm bites and latches on to the dog's intestinal wall. Roundworms are generally found in newborn puppies. The puppy can easily contract worms from its mother's milk, or the roundworm can travel through the placenta while the puppy is still in the womb. The most common symptom of a serious infestation of roundworms in a puppy is an enlarged or bloated belly.