Pet waste is raw sewage that can spread disease. Pet waste can contain disease-causing organisms, including roundworms, ringworms, tapeworms, hookworms, Giardia, Salmonella, E. coli, Cryptosporidium, Toxoplasma, and Parvovirus. Even when pet waste looks like it has washed away, many of these pathogens can survive for days, weeks, months, or sometimes even years in soil and water waiting for a host.
People and pets can come into contact with pathogens found in pet waste while playing in grass, walking barefoot, playing sports, gardening, swimming, fishing, or boating. Children are most susceptible, since they often play in the dirt and put things in their mouths or eyes. Infections from pet waste bacteria often cause fever, muscle aches, headache, vomiting, and diarrhea in humans.
High levels of fecal bacteria can also cause closures in commercial shellfish beds and spread illnesses to pets and wildlife. In addition, the nutrients in pet waste can create harmful algal blooms in lakes that turn the water green and cloudy, use up dissolved oxygen, kill fish and other marine life, and make the water unappealing for recreation.