San Diego County's Tuberculosis Prevention and Care Program has announced a potential exposure to multidrug-resistant tuberculosis (MDR-TB) for California State University San Marcos students and staff.The exposure may have occurred between December 15, 2025, and May 14, 2026, at CSUSM's main campus.Additional brief exposures were reported on the North County Transit District Sprinter during specific times in May 2026.

Health officials emphasize that while short-term contact on the Sprinter is unlikely to cause infection, individuals with certain health conditions may face increased risk.MDR-TB requires more complex treatment than standard tuberculosis, but both are treatable with proper medication.The county warns that TB can be difficult to diagnose, with symptoms potentially taking months to appear.Health officials note a rise in TB cases in San Diego County since 2020, with 247 reported cases in 2024.

They also highlight that approximately 175,000 residents may have latent TB infections, with 5-10% at risk of developing active disease without treatment.Affected individuals are urged to contact the County Tuberculosis Department for screening and guidance.