First positive wastewater sample for the measles found on Maui

The Hawaiʻi Department of Health is monitoring the first-ever detection of the measles virus in Maui County’s wastewater.

The samples were collected two weeks ago on Tuesday, Nov. 18, at two sites in central and west Maui County and tested through the National Wastewater Surveillance System. The virus detected is the naturally occurring type that spreads from person to person, not the weakened form used in vaccines. No suspected measles cases have been identified on Maui.

The Department of Health was notified of Kauaʻi’s first positive wastewater detection of measles in October; at the time, no suspected measles cases were identified on the island.

Each week, municipal wastewater samples across Maui are sent for testing to identify infectious diseases circulating in the community. Wastewater sampling is routinely conducted across Hawaiʻi as part of infectious disease surveillance. It can detect viruses shed by infected individuals, even if they are not showing symptoms or have not reported illness.

The presence of the measles virus in wastewater does not confirm a clinical case or community spread. Instead, it serves as a reliable indicator to be alert for possible measles cases. Measles detected in wastewater likely means that someone infected with the virus was present in the area served by that treatment plant, but wastewater testing cannot determine whether the virus is alive, infectious, or when it was shed.

The State Laboratories Division will continue to work with the National Wastewater Surveillance System to monitor and test wastewater samples to support early detection and public health preparedness.

Measles is also being monitored in wastewater in other areas of the state by WastewaterSCAN.

The Department of Health urges everyone to stay up to date on the measles, mumps, and rubella vaccine. Measles is highly contagious but preventable through vaccination. Infants younger than a year old are at particularly high risk because they are too young to be vaccinated, but in certain situations, vaccination may be recommended for children between six and 12 months if they are exposed to a known case.

To get the measles, mumps, and rubella vaccine, contact a medical provider or pharmacy.

If you traveled to an area with a current measles outbreak, speak with your doctor if you develop symptoms. International and U.S. locations are still experiencing cases of measles, with 43 jurisdictions reporting 1,753 confirmed cases as of Nov. 18, 2025.

A total of 23 measles cases were reported among international visitors to the U.S. The Department of Health will issue a medical advisory to health care providers statewide with information on how to test for measles and current vaccination recommendations.

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.

If you think you have symptoms of measles or were exposed to someone with measles, isolate yourself immediately and contact your health care provider for guidance to avoid further spread.

For more information about measles, visit the Department of Health website, the Centers for Disease Control and Prevention website and the National Wastewater Surveillance System website.