Before revision: Risk of exposure to humans requires: (1) pathogens to survive and be present; (2) pathogens to recreate in surface waters; and (3) individuals to come in contact with water for sufficient time, or ingest sufficient volumes of water to receive an infectious dose.
After revision: Risk of exposure to humans requires: Pathogens to survive and be present; Pathogens to recreate in surface waters; Individuals to come in contact with water for sufficient time, or ingest sufficient volumes of water to receive an infectious dose.