Tests have shown that a US man suffering from the Middle East Respiratory virus, MERS, did not spread it to another person as first reported, health authorities said Wednesday.
That means only two US cases of MERS have been documented so far, not three. Both patients were healthcare workers who became ill while working in Saudi Arabia, and both have recovered.
Further lab tests showed that the Illinois man who was reported to have caught MERS after meeting in May with an Indiana man who had recently traveled to Saudi Arabia actually did not have the virus, the US Centers for Disease Control and Prevention said.
"After completing additional and more definitive laboratory tests, CDC officials have concluded that an Indiana MERS patient did not spread the virus to an Illinois associate during a business meeting they had before the patient became ill and was hospitalized," said a CDC statement.
Initial tests had appeared to show the presence of antibodies that would suggest the Illinois man had a previous MERS infection, the CDC said on May 17.
"CDC scientists have since tested additional blood samples and completed the slower, definitive serology test, the neutralizing antibody test, which requires at least five days before a result is available," the agency said on Wednesday.
"Based on the result of all of these tests, which require careful interpretation, CDC has concluded that the Illinois resident was not previously infected with MERS-CoV."
That would have been the first person-to-person MERS transmission within the United States.
The contagious respiratory illness can cause fever, chills, and sometimes death among people who are older or are already ill.
Of 536 cases reported since April 2012, 145 have been fatal, according to the World Health Organization's latest tally as of May 9.
Most cases have been in Saudi Arabia, but the virus has been imported to more than a dozen other countries. All of those cases have involved people who became ill while in the Middle East.