Measles Virus Detected in Merced Wastewater

The Merced County Department of Public Health detected measles virus in wastewater at the Merced Wastewater Treatment Plant during routine surveillance.

No confirmed measles cases have been reported in the community. The detection signals the virus may be circulating locally, though wastewater surveillance cannot identify infected individuals, their locations, or how many people carry the virus. A positive result may reflect a local case or an infected traveler passing through.

Drinking water remains safe and unaffected by the detection. Merced's wastewater surveillance results are available at WasteWaterSCAN.

Measles symptoms and spread

Measles spreads through the air when infected people breathe, talk, cough, or sneeze. An infected person can transmit the disease four days before a rash appears and four days after.

Early symptoms include fever, cough, runny nose, and conjunctivitis. The characteristic rash typically appears several days after initial symptoms develop.

Vaccination guidance

Two doses of the measles, mumps, and rubella vaccine prevent measles. Children typically receive the first dose at age 12 months and the second at ages 4-6.

Adults born after 1956 need at least one dose if they have no documented immunity. Adults born between 1957 and 1967 who are unsure of their vaccination history should receive one MMR dose.

People born before 1957 or who had measles as children are considered immune. Infants ages 6-11 months need one MMR dose if traveling internationally or to areas with measles activity.

What to do

Residents should confirm their measles vaccination status with their healthcare provider or through the California Department of Public Health's Digital Vaccine Record portal.

Anyone exposed to measles should isolate immediately and contact their healthcare provider. To get vaccinated, call your healthcare provider or the Merced County Department of Public Health Clinic at (209) 381-1023.