The rice looking worms in dog poop are usually going to be tapeworms. The pieces of rice are actually pieces of worm, because tapeworms are long and flat and get segmented and break off easily. The segments are actually filled with eggs which get eaten by fleas and then the fleas will re-infest the dog. Way too much info, huh?
Easy to fix, and make sure you are *very* careful to make sure the dog doesn't step in its feces and then get it anywhere that could cause transmission to human. If you see one form of worm it is likely that there are others present as well (e.g. roundworm is also very common in puppies).
This might be obvious, but until the puppy has been "cleaned", it is very important to maintain very good hygenic practices. For instance, if the dog steps in its fecal, then comes in the house and gets on the couch where someone touches and then later eats it is possible to transmit the infection to humans. Roundworm infections like this are VERY dangerous in humans!
Bring the puppy to the vet as soon as you can to get it dewormed which is a very simple medication.
Enjoy your new puppy!
Puppies are great, and it is a good thing they grow up into dogs! :)
Deworming usually is done first time around age of 3 months and again 6 months later and at least once a year for cats and dogs Typically almost 100% of dogs and cats have worms when dewormed the first time - often- several kind of worms and various scientific papers provide different % of human infections by helminths. However Helminths in humans are very common, the different scientific sources quote numbers in the range of 20-25% global average including similar % in "first world" countries like Europe, etc!! a simple (non-scientific) overview of helminths in human may be found here http://en.wikipedia.org/wiki/Parasitic_worm#Symptoms
The reason why I emphasize helminths in humans is simple. If you have dogs, cats and other pets, you may safely assume they all have at some time some of the many different worms and thus the entire family also is exposed to a far above average risk of having worms unless treated the same way as you do with your pets - under medical control of course.
Heminths actually are very difficult to prove because of the many different varieties and stages in life forms they manifest in a full life cycle. Only a few are living in gastro intestinal part of body. Others may migrate into any body part. Often only indirect and increasing symptoms may lead to find indirect evidence of worms in human body.