Puppies and adult dogs with heavy hookworms can become quite ill. In young dogs and puppies the infestation can be fatal. when pups die from hookworms, they die from the anemia caused by the feeding worms. this can occur very suddenly in the very young animals, sometimes before other symptoms occur. How do I know if my puppy has worms? The most common early signs of intestinal worms in puppies are poor growth, dull hair coat, scrawniness, lack of play and energy and diarrhea. Many of these puppies have bony bodies but potbellied, big tummies. Many are anemic.  if you are bringing home a new puppy its a good suggestion to see a vet within the first 48 hours of receiving your new puppy and get a health and wellness check, bring in a fecal sample and do some basic blood tests. Better to be safe then sorry. If you suspect worms in an existing dog or a senior dog follow the same rule and see a vet. This is a very simple thing to resolve when caught in time so when your puppy poops, go look at it and see if you see anything, just because you cant see anything doesn’t mean your in the clear. So when in doubt, have your puppy checked out.