L.A. County Issues Warnings About West Nile Virus, Measles Exposure

West Nile breeding spaces (Photos – CDC)

Los Angeles County health officials are warning residents about two infectious-disease concerns: a sharp increase in severe West Nile virus cases and a possible measles exposure at Union Station.

By News Desk

West Nile cases reach decade-high pace

The Los Angeles County Department of Public Health has reported 100 West Nile virus infections so far this year—the highest number recorded this early in the mosquito season in nearly a decade. The county is on track for one of its most severe West Nile seasons in recent years.

Nearly all reported patients have experienced severe illness involving the brain or spinal cord, and almost all have required hospitalization. Five deaths have been reported. Cases have occurred throughout Los Angeles County.

The county’s peak mosquito season typically lasts from June through November. Residents are urged to use insect repellent; wear long sleeves and long pants when possible; keep windows and doors screened; and remove standing water, where mosquitoes can breed.

Local vector-control agencies are conducting enhanced surveillance, targeted mosquito-control treatments, disease investigations and community outreach.

Possible measles exposure at Union Station

Public Health is also investigating a measles case involving a visitor who traveled through Los Angeles while contagious.

The person arrived at Union Station, 800 N. Alameda St., on Amtrak’s Southwest Chief, Train 3, on Sept. 12, 2026, and was at the station between 8:00 am and noon. The visitor later departed for Bakersfield at 10:55 am on Amtrak Thruway Bus Route 5717.

People who were at Union Station during that time may be at risk of developing measles for up to 21 days after exposure. The final day to monitor for symptoms is Oct. 3.

People who have had measles or received the recommended measles vaccinations are likely protected, though they should still monitor for symptoms. Those who are unvaccinated or unsure of their vaccination status face a higher risk. Passengers seated near the infected traveler will be notified by local health departments in coordination with the Centers for Disease Control and Prevention.

Health officials urge residents to make sure they are fully protected with the measles-mumps-rubella vaccine, particularly before traveling. Children 12 months and older are considered fully protected after receiving two doses.