The symptoms of bowel worms in puppies include weight loss, diarrhea, an enlarged abdomen, vomiting and a dull coat. Worms may also be visible in the vomit or stool and are usually visible to the naked eye because they are often a few inches long. Some dogs may show no signs of infection, however, which is why it's important to worm all puppies regardless of symptoms present.
The four types of intestinal worms include roundworms, hookworms, tapeworms and whipworms. Only roundworms and tapeworms will be able to be seen in stool or vomit. Roundworms are most often transmitted to puppies while in utero or by nursing from the mother. Whipworms may be more common in certain geographic areas or if the dog spends a lot of time at a kennel. Tapeworms are transmitted to dogs by the dog eating infected fleas, most often when scratching or biting at fleas on the dog. Hookworms can be picked up by the dog eating another infected animal's feces.
Puppies are usually wormed by the breeder starting at 3 weeks of age, but more than one worming is usually needed. Puppies should also receive worming treatments at 8 weeks and 12 weeks when they receive their usual vaccinations.