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Many of our local streams and waterways have fecal bacteria which exceeds our clean water standards. In a 1993 study, the EPA estimated that in watersheds of up to 20-square miles, two to three days of waste from a population of about 100 dogs would result in enough bacteria to temporarily close a bay to swimming and shellfishing.
The DNA testing necessary to identify sources of bacteria is expensive, however, a few agencies have been able to conduct studies locally. The results from these studies are fairly consistent and can be applied to other developed areas.
A 1999 study by the City of Vancouver indicated that dogs and cats contributed 7.4% of fecal coliform found in Burnt Bridge Creek; Clean Water Services in Hillsboro, Oregon found that over 13% of the fecal coliform in the Tualatin River Watershed was of canine origin; and the EPA notes that over 20% of bacteria found in the area around Seattle came from dogs.
In addition to E. Coli, dog waste can transmit organisms such as giardia and roundworm, which can stay in your yard for years -- long after the poop itself has decomposed.
Leaving poop in the park or your yard also means dogs are likely to eat it. Not only is this gross, it’s exactly how the dangerous canine virus Parvo is spread.
The table below lists some of the organisms and pathogens that can be found in dog waste:
|
Organism |
Common Name |
Survival |
Human Disease |
|
Toxocara canis |
Roundworms |
4 years in soil. |
VLM (visceral larva migrans) leading to hepatomegaly, myocarditis, nephritis, pulmonary inflammation, and blindness, usually in children. |
|
Baylisascaris |
Roundworms |
Eggs can survive on moist soil for years. |
Severe neurological form of VLM, especially in young children (see Toxocara) |
|
Ancylostoma spp. |
Hookworms |
Several days. No known effective chemical or pesticide. Prompt removal of dog and cat feces greatly reduces risk of infection. |
Spreading lesions and severe pruritis. In rare instances can cause symptoms like VLM (see Toxocara). Puppies are a significant source of infection. |
|
Cryptosporidium |
|
At least 6 months. Susceptible to drying. |
Self-limiting gastroenteritis, protracted in susceptible individuals. CDC reports 300,000 cases annually, 90% of waterborne origin. |
|
Campylobacter spp. |
|
Rapidly killed by heat, drying, and freezing. |
Mild to severe, bloody diarrhea. |
|
Escherichia coli |
E. coli, Fecal coliform bacteria |
Up to 4 months in ruminant feces. Extended exposure (i.e., 3 days) at 140˚F required to kill organism. |
Bloody diarrhea, severe cramps, HUS (leading to kidney failure), and TPC. |
|
Giardia duodenalis |
Giardia, Giardiasis |
Resistant to drying, chlorination, and temperature extremes. Can survive for months in water and are relatively persistent during wastewater treatment. |
Diarrhea, cramps, flatulence, nausea, steatorrhea. Can be protracted and debilitating. CDC estimates 2 million cases in U.S., 90% of waterborne origin. |
|
Salmonella spp. |
|
Up to 6 months in cattle feces. Extended exposure at 140˚F required to kill organism. |
Usually mild gastroenteritis within 6-48 hours. |
|
Brucella spp. |
Brucellosis |
2½ months in moist soil. Rapidly killed by exposure to direct sunlight. |
Brucellosis symptoms appear in days to months. Can be protracted and extremely debilitating. Uncommon in U.S. |
|
Yersinia enterocolitica |
|
Unknown. |
Gastroenteritis. |
|
Leptospira interrogans |
Leptospirosis |
Weeks to months in soil or water. |
Usually mild fever but complications can be serious, including hepatitis, jaundice, meningitis, and kidney failure. Life threatening, but uncommon. There has been a recent increase in the numbers of dogs with Leptospires. |
