WISCONSIN (CBS 58) -- State health officials in Wisconsin are investigating a cluster of people with lung disease believed to have been caused by vaping. 

As of September 12, there are 35 cases in Wisconsin, up from 34 last week. Counties with cases include Dane, Dodge, Door, Green, Kenosha, La Crosse, Milwaukee, Portage, Racine, Sauk, Sheboygan, Walworth, Washington, Waukesha, and Winnebago. 

Health officials say most of the cases involve teenagers or young adults but some older adults have also been affected. 

Most of the patients developed severe respiratory illness requiring hospitalization. 

No deaths related to vaping have been reported in Wisconsin.