TUESDAY, May 13, 2014 (HealthDay News) -- Two Florida hospital workers who helped treat a man with the second diagnosed case of MERS in the United States have developed respiratory symptoms, according to published reports.

The workers are being tested to see if they may have caught the potentially fatal virus from the man, hospital officials said.

One of the cases probably isn't MERS because the worker started experiencing symptoms just one day after treating the 44-year-old patient. The incubation period for MERS is typically five days, NBC News reported Tuesday.

"We want to be extra cautious," said Dr. Antonio Crespo, infectious disease specialist and chief quality officer for the P. Phillips Hospital in Orlando. "These two people were in contact with the patient without a mask."

One of the staffers was sent home after treatment. The other one is in a special isolation room at the hospital, as is the MERS patient, NBC News reported.

The MERS virus first surfaced in the Middle East two years ago, and the vast majority of cases have been reported in that region of the world.

News of the second U.S. case of MERS was announced Monday by federal health officials.

Like the first U.S. case identified earlier this month, the second case involved a health care provider who lived and worked in Saudi Arabia, the epicenter of the MERS outbreak. The second patient -- an unidentified man -- was being treated at the Orlando hospital and was said to be doing well.

The health risk to the general public is very low, federal officials said Monday, because the virus is only passed through close contact.

The second patient worked in a facility in Saudi Arabia that cared for MERS patients. The patient was visiting family in central Florida before entering the hospital. The patient had traveled from Saudi Arabia to London to Boston to Atlanta, before reaching Florida, officials said.

The patient felt unwell on a May 1 flight to London, but sought care in Orlando. The U.S. Centers for Disease Control and Prevention said it has notified all passengers on the affected flights to be on the lookout for symptoms.