Waterborne Disease Outbreaks

Cause: Many infectious agents including viruses, bacteria, and parasites. Common agents are norovirus, Giardia, and Cryptosporidium. Bacterial agents are less commonly implicated.

Illness and treatment: Symptoms and treatment vary with the agent.

Sources: Sources vary with the agent. Waterborne outbreaks can occur from ingestion of natural or recreational water, including pools, interactive fountains, and untreated drinking water.

Additional risks: Risks vary with the agent.

Prevention: Test private wells at least every 3 years and after potential contamination such as after floods. If ill with diarrhea do not enter recreational water, pools, or interactive fountains.

Recent Washington trends: Waterborne outbreaks are often difficult to detect. There are 0 to 3 outbreaks reported each year, each with 2 to dozens or even hundreds of cases.

Purpose of Reporting and Surveillance

To prevent tranmission from infected persons.
To identify and correct sources of exposure for waterborne disease (WBD) outbreaks.
To prevent further exposures to contaminated water and limit outbreaks.
To expand current understanding of the transmission, pathogenesis and community impact of illness caused by known WBD agents.
To identify new WBD agents, hazards or gaps in the water safety system.

Legal Reporting Requirements

Health care providers and Health care facilities: Outbreaks immediately notifiable to local health jurisdiction
Laboratories: No requirements for reporting WBD outbreaks; see disease-specific reporting requirements
Local health jurisdictions: Outbreaks immediately notifiable to the Washington State Department of Health (DOH) Communicable Disease Epidemiology (CDE)

Note: Individual confirmed or probable cases of specific conditions may have other specific reporting requirements; refer to disease-specific guidelines.