Measles turns up in Anchorage wastewater

Measles virus showed up four times in Anchorage wastewater in early July, and clinicians are being told to isolate any suspected case immediately rather than wait for laboratory confirmation.

The Alaska Section of Epidemiology issued the alert Monday. Concentrations were very low.

No human case has been confirmed. Wastewater cannot confirm an infection, identify a source or show that transmission is happening. Measles spreads through air, not sewage. What the sampling can do is catch the virus before anyone walks into a clinic, which is why the state treats it as an early warning.

The sampled sewershed covers Anchorage and Joint Base Elmendorf-Richardson. Eagle River and Girdwood are not included.

Nationally, measles is running at levels not seen in more than 35 years. Alaska's vaccination rates sit below the roughly 95 percent coverage generally considered necessary to stop it spreading: 55 percent of children 19 to 35 months old have completed the seven-vaccine series, and 77 percent of kindergarteners have both MMR doses. Anchorage confirmed a case in an unvaccinated minor in May 2025.

The surveillance has blind spots. A CDC review found standard assays missed a genotype behind roughly 5 to 10 percent of U.S. cases in 2025, and detections do not always match recognized local cases.