CNN News:美国疾控中心调查电子烟与肺病是否相关

From California to Connecticut, at least 15 U.S. states have identified dozens of cases of lung disease and they might be connected to vaping. It's another term for inhaling vapor from electronic cigarettes. Health officials in several states say they're not sure if vaping definitively caused more than 120 people nationwide to get sick. But the U.S. Centers for Disease Control is investigating. Some of the patients with lung disease have been in the hospital for weeks. Their symptoms include fevers, dizziness, chest pain, coughing, stomach problems and having trouble breathing.

States are not required to report lung diseases related to vaping, so experts say the issue could be difficult to keep track of. But in Wisconsin, the state with the most confirmed and suspected cases, a respiratory disease specialist said they involved otherwise healthy young people who had severe respiratory illnesses and no signs of infection. Wisconsin's government says all of the patients had said they vaped before they were hospitalized but what's not known is exactly what products they vaped. It's possible but not certain that they were mixed with other chemicals. E-cigarettes are relatively new and health experts don't know yet what kinds of short and long term risks they carry.