The most common complaint about unremoved faecal deposits is the effect on aesthetics and the unpleasant experience of dodging droppings on footpaths and in parks. The most serious concerns are health related. Faeces may be infested with microscopic parasitic organisms that can be transmitted to and cause disease in humans. Although the risk to humans is slight, roundworm is the most prominent health concern in relation to dog faeces.
Roundworm resides in the small intestine of dogs.
Its eggs are passed to the outside environment in the dog's faeces. The eggs take two weeks to a month to become infective, so there is no risk from fresh faeces. However, the eggs may remain infective in the soil for years. Humans do not develop adult roundworms, however migration of larvae through the tissues and organs can cause disease. The primary transmission pathway to humans is through contamination of the hands by eggs in the soil and accidental ingestion.