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.