The Hawai‘i Department of Health (DOH) is closely monitoring a positive wastewater sample for measles virus, which marks the first wastewater detection of the virus in the state.

On August 11, the sample was collected at a site in West Hawai‘i County, and DOH was notified of the result on Aug. 26.  As of yesterday, no suspected measles cases have been reported.

Wastewater sampling is routinely conducted across Hawai‘i as part of infectious disease surveillance. It can detect viral genetic material shed by infected individuals, even if they are not showing symptoms or have not reported illness. Testing for measles virus was added to surveillance in 2025, through WastewaterSCAN in May, NWSS-Verily in July, and Biobot Analytics in August.

The presence of measles virus in wastewater does not confirm a clinical case or community spread. Instead, it signals DOH to be alert and prepared for possible measles cases. The two confirmed measles cases in Hawai‘i in April 2025 occurred before measles wastewater testing began and are not related to this current wastewater detection.

Measles symptoms usually start with a high fever, cough, runny nose, and red eyes, followed by a rash of tiny red spots that begins at the head and spreads downward. The disease can lead to serious complications, including pneumonia, neurological illness, and death.