If you encounter diarrhea, lethargy, and you see your newly acquired puppy overall unwell, and with a lack of energy, think about these parasites, as they deprive your Pap of fundamental nutrients.
The good part is that it can be easily treated by your veterinarian.
Also know that a puppy you just purchased from a breeder can easily carry those bugs around for a good number of days without showing any symptoms. Stress like traveling, new environment, new people can easily "trigger" a bout of diarrhea with symptoms as described above.
Bring some of the puppy's stool to the vet and let him confirm parasites.
Both parasites live in the ground everywhere, and are almost unavoidable. Older dogs do establish a certain immunity to these bugs, but they are not excluded!