What happens if we don't pick up the dog's excrement? 

Beyond the social responsibility, respect for others, education and culture, leaving the dregs of our dog in the park, the street, the forest or the beach can be very harmful to the health of all who share the planet.
The main consequence is the "ZOONOSIS". But what is that? Zoonosis is the term referring to diseases that humans can acquire by other species; for example through the feces of our dogs we can acquire parasitic zoonosis caused by cysts, eggs, larvae and worms. Some of the diseases that are transmitted through feces are typhoid, salmonella, hepatitis A, leptospirosis, among many others. These parasites can enter our body by ingestion ...
Why intake? ... But How could you eat the feces of a dog? In fact it is very likely that you have done, without realizing it. If any particle of poop was in your shoes, in your dog's paws or their toys, hands and / or children's shoes, any object that has been in contact with the remnants of feces left in the park will be carrier from the same. Stool particles come to your house and your house to your mouth will be one step.