A patient who had recently been vaping has died in the US after developing severe lung disease, officials said Friday, as authorities scrambled to find the cause behind almost 200 more potential cases. As of Friday, there were 193 cases across 22 states of potential cases of severe lung illness associated with e-cigarette use since the end of June, according to figures released by the Centers for Disease Control and Prevention. The cause has not been determined but all had recently used e-cigarettes to inhale either vaporized nicotine or cannabis, and many of the products have been sent for lab testing. No specific product has been identified or blamed for the illness in any of the cases. E-cigarettes have been available in the US since 2006, and are sometimes used as an aid to quit smoking traditional tobacco products like cigarettes.