Outbreaks Associated with Ingesting Water from Freshwater Sources in Outdoor Settings-United States, 2000-2022

IntroductionFreshwater sources (eg, lakes, ponds, rivers, or streams) can be contaminated by pathogens. Ingesting water from these sources can cause illness if the water is insufficiently treated.MethodThe Waterborne Disease and Outbreak Surveillance System (WBDOSS) collects data on waterborne disease outbreaks associated with drinking water, recreational water, other nonrecreational water, and undetermined exposures to water. We analyzed outbreaks reported to WBDOSS that involved ingesting water from freshwater sources in outdoor settings.ResultFrom 2000 through 2022, public health officials in 16 jurisdictions reported 32 outbreaks associated with ingesting water from insufficiently treated freshwater sources. These outbreaks resulted in 437 illnesses, 4 hospitalizations, and no reported deaths. Giardia was implicated in 69% of outbreaks, and Campylobacter was implicated in 28% of total cases. Water from rivers or streams was implicated in 75% of outbreaks. In half the reported outbreaks, water treatment was not attempted. Individuals were primarily exposed in outdoor recreational areas (eg, public outdoor areas, state parks, campgrounds), with most illnesses occurring in those aged 10-19 years.ConclusionThis is the first summary dedicated to outbreaks associated with ingesting freshwater. These outbreaks can be mitigated using potable water sources, when available, or appropriate water treatment. Public health and provider efforts could include engaging the public-especially those who spend time in the backcountry-regarding health risks and encouraging hygiene, safe disposal of feces, and recommended water treatment methods. Healthcare providers should be encouraged to ask individuals about potential exposure to water from outdoor freshwater sources when presenting with gastrointestinal illness.