Health officials in eastern Nebraska say they're investigating a string of tuberculosis cases in the Omaha area. Television station KETV reports that the Douglas County Health Department said Wednesday that 13 people have tested positive for latent tuberculosis, and one child has a confirmed active case of the lung infection. The department says it has tested 31 people since December, when it learned a person from out-of-state staying with family was diagnosed with TB. Common symptoms of TB include unexplained rapid weight loss, profuse coughing, night sweats and fever. It is treated with a course of antimicrobial drugs.