PORTLAND, Ore.--Oregon Health Authority is alerting health care workers to a detection of measles found in a sewage sample through routine wastewater testing.  Wastewater testing, an early warning system, indicates at least one person with measles was in an area. OHA and Marion County health officials say health care providers should remain vigilant monitoring for patients who might have measles, and members of the public should ensure they are up to date on measles vaccination.  “One way to think about wastewater surveillance is like a ping on a radar -- it could be low levels of the virus just passing through or something more serious, like an outbreak,” says Howard Chiou, M.D., Ph.D., medical director of communicable disease and immunizations at OHA. “It gives us a chance to prepare our health care partners with information they can use to help patients take steps to protect themselves, including reminding them to be up to date on their measles vaccines.”  View video clips of Dr. Chiou discussing the measles detection and wastewater surveillance. A link to broadcast-quality clips for media is available upon request.  The positive sample was collected Oct. 6 from a wastewater treatment plant in Marion County. The detection means there was at least one person infected with measles virus within the local area serviced by the wastewater treatment plant.  The health care alert is precautionary, as a single positive wastewater test result does not show whether there is ongoing risk to the community. The positive detection may have come from a person simply traveling through the area.  The alert is sent via the Health Alert Network (HAN), which facilitates information sharing between hospitals, clinics, laboratories, public safety, EMS and other public health partners throughout Oregon and Southwest Washington.