When people use the generic term worms in describing puppy parasites, they are usually talking about roundworms, or ascarids. That's because hardly a single puppy avoids being born infested with the pest. But puppies can also be plagued by other intestinal parasites such as hookworms, whipworms, tapeworms, and single-cell parasites such as coccidia and giardia.
Left untreated, intestinal parasites can stunt growth and weaken young animals. Worms — roundworms in particular — can present a danger to humans — especially to children, who often aren't as careful around pets as adults are. As with most diseases transmitted from animals to humans — rabies being the most deadly exception — sensible sanitary measures such as keeping pet areas picked up and hands clean minimize the risk of transmission.
The cure for intestinal parasites is easy, if a little repetitious. First, the puppy's stools are examined for signs of infestation at the veterinary hospital, and your veterinarian then prescribes the appropriate drug to kill the parasites. Puppies should be wormed every two weeks from birth on, until a fecal examination reveals no sign of parasites.
Worming medication is available over-the-counter. The problem is, some intestinal worms and other parasites can be treated with medications available by prescription only. Treating your pet for worms he doesn't have is not a good idea; neither is mistreating him for worms he does — while thinking that the medication you've purchased is doing the job.
The only way to be sure which parasites your puppy is carrying is to have his stool examined by a veterinarian.
The mosquito-transmitted heartworm is an internal parasite that's better prevented than treated, even though recent advances have made eliminating the pest safer for pets.
Puppies whose mothers were on preventive medication can continue on daily or monthly medication, starting from about the time of your puppy's first exam. The preventives often contain medications to control intestinal parasites as well. Once your pet has been started on preventive medicine from your veterinarian, a once-monthly dose for the rest of his life will keep heartworms from bedeviling your dog.