LANSING, MI (My TV20 News at 10 --- David Kwiatkowski did more than treat patients at four local hospitals.
Federal investigators believe he also made many of them sick.
They claim Kwiatkowski infected them and others with Hepatitis C while he worked at four hospitals over a two year period.
Kwiatkowski worked at Detroit's Sinai Grace from June 2005 to October 2005.
He left, and started the same month at Detroit's Harper Hospital, before he quit roughly a year later.
Kwiatkowski went to Ann Arbor's University of Michigan Hospital, from September 11, 2006, and stayed there until December 8 of the same year.
The last local hospital he worked turned out to be Oakwood Annapolis, in Wayne, where he stayed from January 15 2007 to September 15 of the same year.
The Michigan Health Department tells us Kwiatkowski tested negative for Hepatitis C while employed at another hospital.
Health investigators excluded that hospital and another one from the list.
They're not releasing the names of those hospitals to avoid a panic.
We're told Kwiatkowski has been infected with hepatitis C since at least June 2010.
Hepatitis C can cause inflammation of the liver.
That may lead to chronic health issues.
It's estimated Hepatitis C affects about 1.5 percent of the U.S. population.
We also want to remind you, what to do if you believe you may have been infected with Hepatitis C, contact that hospital or primary care provider.
You can learn more about Hepatitis C by logging onto www.tv20detroit.com. and clicking on "news links."