A patient in Illinois is the first to die of a mysterious lung illness linked to vaping, public health officials announced today.

The death occurred as doctors and hospitals nationwide report an increasing number of vaping-related respiratory illnesses this summer: 193 cases have been reported in 22 states, including 22 cases in Illinois, officials said.

They have been stumped in recent weeks by the cause. State investigators have not found a common link — other than vaping in general — among the patients turning up in emergency rooms.

Many patients have acknowledged vaping tetrahydrocannabinol, or THC, the high-inducing chemical in marijuana, according to statements from federal and state health agencies.

But officials don’t know whether the ailments have been caused by marijuana-type products, e-cigarettes, or some type of street concoction that was vaped, or whether a contaminant or defective device may have been involved.

The Illinois patient’s death was disclosed during a news conference held by officials at the Centers for Disease Control and Prevention, the Food and Drug Administration and the state of Illinois.

They did not provide details about the patient’s identity, saying only that the person was an adult who had vaped recently and then succumbed to a severe respiratory illness.

Health officials did not say what product the patient had used, whether an e-cigarette or other vaping device; nor did they specify what substance was vaped.

Amid the lack of information, investigators are scrambling to find shared links to the respiratory problems. Officials said this week that many patients, most of whom were adolescents or young adults, had described difficulty breathing, chest pain, vomiting and fatigue.

The most seriously ill patients have had extensive lung damage that required treatment with oxygen and days on a ventilator. Some are expected to have permanent lung damage.

“We’re at a relatively early stage of understanding,” Mitchell Zeller, director for the Center for Tobacco Products at the FDA, said today. The collective agencies were throwing “a lot of resources at this,” he added, but part of the problem was that state investigations are not always complete, making it difficult to form a clear picture.