A traveler infected with measles has journeyed across California using Amtrak trains and buses before being hospitalized, leading state health officials to issue a warning for thousands of passengers who might have been exposed.
This individual, who is unvaccinated, moved through six California counties in three days—Los Angeles, Kern, Sacramento, San Joaquin, Alameda, and Butte—before heading to Denver, as reported by the California Department of Public Health.
The person arrived in Los Angeles from Chicago on an Amtrak train on September 12.
In the following three days, the infected traveler utilized both trains and buses, with stops in cities including Bakersfield, Stockton, Oroville, Sacramento, and Emeryville before making their way to Denver.
Detailed information regarding the specific routes, stations, and times of potential exposure can be found in the public health resources.
Anyone who was at these locations during the mentioned time slots might have been put at risk, health officials cautioned.
Symptoms may develop seven to ten days after exposure; these can include fever, cough, runny nose, red eyes, and a rash.
Dr. Rita Nguyen, an Assistant State Public Health Officer, stated, “Measles is among the most contagious diseases, leading to severe lifelong consequences such as permanent brain damage or even death, particularly in children.” She emphasized the safety and efficacy of the measles-mumps-rubella (MMR) vaccine, which offers long-term protection against the disease. Vaccination not only safeguards families but also helps protect those who are too young to be immunized.
Unvaccinated individuals are advised to quarantine, steer clear of large gatherings, and keep an eye out for any signs of illness for the next three weeks.
Officials highlighted that pregnant women, infants, those with compromised immune systems, and unvaccinated individuals should seek medical advice immediately if they suspect exposure.
State health authorities are collaborating with federal and local officials to conduct contact tracing related to the exposure sites.
In light of this situation and the ongoing spread of measles in other regions of the U.S. and globally, the California Department of Public Health has urged residents to ensure they are fully vaccinated against measles.
If anyone starts showing symptoms, they should reach out to a healthcare provider before visiting in person, in order to minimize the risk of spreading this highly contagious virus.
As of September 14, 2026, California reported a total of 59 measles cases, with about 94% of those involving unvaccinated individuals or those whose vaccination status was unclear.
