Environmental investigation of a hepatitis A outbreak associated with spring water consumption in an Anabaptist community: Kentucky, 2018–2019

In 2019, a hepatitis A outbreak in an Anabaptist community was reported to the Kentucky Department for Public Health. Epidemiological data suggested untreated spring water as a potential outbreak exposure. An environmental investigation was conducted to evaluate this less common hepatitis A virus (HAV) exposure source. We collected water samples from the main spring used for drinking and produce irrigation by the primary household where cases were identified, from springs feeding the main spring, and from the household's gray water discharge and human waste systems. Samples were tested for HAV, and viral and bacterial fecal indicators. HAV was detected in the main spring water and downstream of the household gray water discharge pipe. HAV was repeatedly detected in the follow-up samples from spring water and in wastewater from a new septic system. The environmental investigation confirmed HAV contamination of the household drinking water. Human-specific and general fecal indicators indicated a hydrological connection between the waste system and the drinking water source. Given that private springs are unregulated in the United States, spring water should be considered as a risk factor in HAV and other waterborne virus outbreaks within communities less likely to utilize water treatment systems.