A disturbing health alert has emerged from a Southern California college campus, where authorities have disclosed potential exposure to a perilous, drug-resistant tuberculosis strain among students and staff.

On Thursday, health officials in San Diego County issued a warning that anyone who visited Southwestern Community College in Chula Vista from late October to mid-December 2025 might have come into contact with this difficult-to-treat pathogen.

The concern centers around multidrug-resistant tuberculosis (MDR-TB), a particularly severe variant of the disease. Unlike typical strains, MDR-TB does not respond to conventional antibiotic treatments, posing significant challenges in terms of treatment duration and complexity.

Authorities are urgently working to trace and inform all individuals who might have been exposed.

Medical professionals emphasize the heightened risk associated with MDR-TB.

“The positive aspect is that TB, including its MDR form, can be treated and cured with appropriate medication,” stated San Diego Public Health Officer Sayone Thihalolipavan, highlighting the importance of prompt screening.

The disease spreads through the air — when an infected person coughs, speaks, or even breathes — meaning crowded indoor settings like classrooms can increase the risk of transmission.

Anyone who spent extended time on campus during the exposure window could be affected, though brief contact carries a lower risk, officials said.  

Those who test positive but show no symptoms likely have latent TB, meaning the bacteria is present but inactive. Still, without treatment, about 5% to 10% of latent cases can turn into active cases if left untreated, according to health officials.

But the delayed discovery highlights a chilling reality: TB can go undetected for months, silently spreading before a diagnosis is made.  

San Diego County already has an estimated 175,000 people living with latent TB infections, underscoring how widespread the underlying condition can be. The warning comes as tuberculosis cases have been climbing in recent years, with hundreds of active cases reported annually. Still, MDR-TB remains relatively rare, with experts reporting just three in 2024, and two in 2025 in San Diego County.