Tuberculosis cases are rising again in California, and health officials are urging those at higher risk, as well as doctors, to be alert for the disease, which can lurk in people’s bodies for years before becoming potentially deadly.

The number of tuberculosis cases in 2023 rose by 15% in California compared with the previous year, the state Department of Public Health said. That’s the highest year-over-year increase since 1989, when it was tied to people co-infected with HIV.

There were 2,113 cases across California last year; that’s about the same amount reported in 2019, before the COVID-19 pandemic. Seniors 65 and older had the highest percentage increase in cases from 2022 to 2023.

Tuberculosis rates also are rising nationally, up 16% in 2023 compared with the previous year, the U.S. Centers for Disease Control and Prevention said Thursday. The 9,615 cases provisionally reported last year were the highest since 2013 and were 8% higher than the tally of 8,895 cases reported in 2019.

Those at major risk for tuberculosis include people who have lived outside the U.S. where the TB rate is high, including most nations in Asia, the Middle East, Africa, Eastern Europe and Latin America.