Arizona health authorities and Maricopa County, Arizona, public health officials have been told the man worked briefly in Maricopa County during 2009 and 2010 "for a temporary health care staffing agency." It is not known exactly where he worked.
"We are in the process of confirming details so that we may accurately inform the public of any potential risk and actions to take," said Bob England, director of the Maricopa County Department of Public Health
Johns Hopkins is calling in about 200 patients who had a procedure at the lab during the time Kwiatkowski worked there. About 460 patients had procedures at the lab in Kansas during Kwiatkowski's stint there.
But the number of people who may be tested might change as officials peruse medical records and see who needs to be seen.
These and the other institutions are calling old patients in and offering free testing. The U.S. Centers for Disease Control and Prevention is helping state health officers and hospitals tackle the problem.
Like Exeter and New Hampshire, other hospitals and states are, as Johns Hopkins puts it, "erring on the side of patient safety and contacting anyone who came in during that time."
"He didn't necessarily have contact with all patients who were at the lab during that time period," said a statement from Johns Hopkins.
Kansas Department of Health and Environment Secretary and State Health Officer Robert Moser said he understands patient concerns but is reassuring people that "we have no reason to be concerned about additional risks to the public" because Kwiatkowski worked in Kansas two years ago.
Authorities across the United States want to know as much as they can about Kwiatkowski's whereabouts since he became infected. The New York health department asked the state's hospitals and radiology facilities to identify any place where Kwiatkowski might have worked since January 1, 2007, either as a facility employee or as a "traveler" employed by a contracting agency.
Kwiatkowski was arrested earlier this month in a Massachusetts hospital where he was being treated. He is now being held in the Strafford County, New Hampshire, jail. He could face more than 20 years in prison if convicted.
"The evidence gathered to date points irrefutably to Kwiatkowski as the source of the hepatitis C outbreak at Exeter Hospital. With his arrest, we have eliminated the menace this 'serial infector' posed to public health and safety," U.S. Attorney John P. Kacavas in New Hampshire said.
Kwiatkowski appeared in New Hampshire federal court Tuesday and waived his right to a detention hearing. Kacavas said it is possible more charges could be filed.
A negligence complaint and a class action lawsuit have been filed in U.S. District Court in Omaha, Nebraska, against Triage Staffing, a health care company that hired and placed Kwiatkowski at Exeter.
One of the cases, filed by Seabrook, New Hampshire, resident Robert Oliver Fowler claimed Kwiatkowski was negligently hired and retained.
"Triage failed to exercise reasonable care in view of all of the circumstances surrounding the job Mr. Kwiatkowski was to perform at Exeter Hospital. Triage failed to exercise the degree of care required related to the severity of risk to Mr. Fowler. Triage knew or should have known of Mr. Kwiatkowski's likelihood of causing harm to Mr. Fowler when it supervised Mr. Kwiatkowski. Triage failed to conduct a reasonable investigation that could have found Mr. Kwiatkowski's likelihood of causing harm to Mr. Fowler," the suit said.
Joe M. Grillo, a spokesman for Triage Staffing, told CNN in an e-mail that "we are aware of issues involving a former contract medical technologist at Exeter Hospital. Given that there is an ongoing criminal investigation, as well as pending civil litigation, it would be inappropriate for us to comment at this time."
Fowler's attorney, Domenic Paolini of Boston, said firms like Triage need to perform due diligence in vetting employees. At present, he said, a cashier at a hardware store gets "more scrutiny" for hiring than people working in important health care jobs.
Firms that employ traveling health care workers need to rethink their hiring procedures, he said, and "hospital policies and procedures need to be changed as well."