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. Direct contact between humans and infected dogs does not play a role in disease transmission.
Young children have the greatest risk of exposure.
They may inadvertently eat dirt or grass or touch their mouths with hands contaminated with old dog faeces containing infective roundworm eggs. Preventative measures will reduce the public risks. The roundworm is not present in dogs that are correctly and regularly treated for worms and dog owners should be made fully aware of their responsibilities in this regard. Removal of faeces before the roundworm eggs become infective is also important. The spread of hydatids is another potential health concern associated with dog faeces.