"We are working closely with both hospitals to conduct a targeted investigation and ensure all affected parties are properly notified about their potential exposure to the disease," said Pensylvania Secretary of Health Eli Avila.
There is no evidence that any patients were infected here, Avila said in a statement, but an investation by the hospitals, state and local health departments is continuing.
Authorities in New Hampshire said Kwiatkowski, 33, injected himself with anesthetic drugs stolen from a lab at Exeter Hospital, contaminating syringes that were later used on patients. Thirty patients have been diagnosed with the strain of hepatitis C that Kwiatkowski carries.
Testing has been recommended for about 4,700 people in New Hampshire alone, and officials are still determining who should be tested elsewhere. Health officials have confirmed that Kwiatkowski worked in Georgia, Kansas, Maryland, Michigan, New York and Pennsylvania before being hired in New Hampshire in April 2011.
Kwiatkowski told authorities he did not steal or use drugs. He said he learned he had hepatitis C in May, but authorities say there is evidence that he was diagnosed as early as June 2010.
The virus can be present for decades without symptoms. Hepatitis C is a major cause of liver damage and the top reason for liver transplants in the United States.
His work at Temple is still being investigated.
"We have no evidence at this time that Mr. Kwiatkowski engaged in any illegal activies during the three weeks he worked here temporarily," Temple spokeswoman Rebecca Harmon said.
As officials across the country filled in the gaps on Kwiatkowski's resume, a hospital administrator in Arizona said he had been fired from her facility in April 2010 - that date would make it around the time he was hired by Temple - after being found unresponsive in a men's locker room with syringes.
He was treated at the hospital, and tests showed he had cocaine and marijuana in his system, said Monica Bowman, CEO of the Arizona Heart Hospital.
In Pittsburgh, UPMC said in a written statement that Kwiatkowski had been "terminated after being found in an area of the hospital where he was not assigned."
U.S. Attorney John Kacavas said Thursday in New Hampshire that while other health care workers have been prosecuted for diverting drugs and infecting patients, this case stands apart.
"Because of his employment as a traveler, working for agencies and being sent around the country to various states, it really has tentacles all over the country," he said.
"Its scope is unprecedented and scary."
Staff writer Don Sapatkin contributed to this article.