CHICAGO (WLS) -- Illinois saw its first increase in the number of tuberculosis cases since 2005.
More than 340 cases were reported last year, including one case of "extensively" drug-resistant tuberculosis.
State health officials said that case is concerning because antibiotics used to treat the disease did not work.
Tuberculosis is contagious and potentially life-threatening. It is transmitted through the air.
Thursday is World TB Day. It seeks to raise awareness that TB patients must complete their treatment, which takes six to 12 months.
Tuberculosis cases on the rise in Illinois