It almost sounds like a round worm.. Is he still a puppy?
You can go to the vets and get him some pills. I just did Presley because she is always getting into the horse poops. The horses don't have worms but i don't want to take any chances. If you know his weight and ask the lady at the front counter for some worm pills you should be fine

BTW if one has them it is more then likly they both will.. We worm all our animals at the same time horses,cat, and Presley and our cats never go outside....