There are many articles that can be found on the importance of maintaining a clean environment - eliminating feces - for your pets. You can find a lot written on the subject at www.thepetcenter.com. The following information was obtained from this web site:

Roundworms, tapeworms, hookworms and whipworms can be found in dogs and cats. These worms and other intestinal parasites such as giardia and coccidia can potentially be health hazards for humans as well.  To prevent these parasites dog feces should be removed from yards at least weekly.  If you walk your dog, picking up after him/her is also important.

Scoop in Time will let you know if we see anything in the feces that we think is abnormal and will provide a stool sample free of charge.  In order to prevent transference of any unwanted parasites, we disinfect our tools and shoes after each cleanup.