CONCORD, N.H. -- New Hampshire health officials are expanding the list of people who may have contracted hepatitis C from a traveling medical technician.

Public health director Dr. Jose Montero said Tuesday that testing is being recommended for anyone who had surgery at Exeter Hospital or was admitted to the intensive care unit between April 1, 2011, and May 25, 2012.

On the same day, Kwiatkowski faced a federal magistrate, and charges that he acquired drugs by fraud or deception and tampered with a consumer product, placing others at risk.

“We’re talking about eight states including New Hampshire in an untold number of cases,” said John Kacavas, U.S. attorney.

Kacavas believes Kwiatkowski infected at least 31 other people with hepatitis C at Exeter Hospital beginning in the spring of last year.

An FBI affidavit states investigators found “three empty syringes bearing Fentanyl labels on his person.” His coworkers said he was “shaky and very sweaty” at work, sometimes even vomiting.

“It is a circumstantial case. There’s no question about that. But given our epidemiological testing results, the evidence is circumstantial but in our view strong,” Kacavas said.

When asked how dozens of patients could suddenly become infected with the same strain of hepatitis C he has, the defendant allegedly said, “You know, I’m more concerned about myself,” and denied being an addict.

In the meantime, N.H. public health officials are asking that 6,000 people be tested for hepatitis C. They have new information that Kwiatkowski had access to not only the cardiac catheterization lab at Exeter Hospital, but also to the ICU and areas where surgeries are performed.

David Kwiatkowski was charged last week with federal drug crimes. Authorities say he's worked in at least six states.

Thirty people are believed to have contracted the illness from Kwiatkowski.