ORLANDO, FLa. -

The Centers for Disease Control has confirmed that a health-care professional visiting Orlando from Saudi Arabia was diagnosed with MERS -- the second case in the United States of the mysterious virus that has sickened hundreds in the Middle East.

Health officials announced Monday afternoon that the patient is isolated in a Central Florida hospital and is doing well. Officials said the patient was working in a facility in Saudi Arabia that was caring for another MERS patient before coming to the United States.

MERS -- Middle East Respiratory Syndrome -- is an illness that begins with flu-like fever and cough but can lead to shortness of breath, pneumonia and death. A third of those who develop symptoms die from it.

The CDC said that while the virus does not spread easily person to person and requires very close contact, health officials were attempting to contact people who have come in close contact with the man during his visit and on the flights he took to London, Boston and Orlando.

Most MERS cases have been in Saudi Arabia or the Middle East, but earlier this month a first U.S. case was diagnosed in a man who traveled from Saudi Arabia to Indiana.

"Since March 2014 there has been a substantial increase in the number of MERS cases reported worldwide," said Assistant Surgeon General Anne Schuchat.

She said there have been 538 confirmed cases worldwide and 145 deaths.

Kelli Wells, director of the Duval County Health Department, said health officials have been monitoring MERS since they identified the first case two years ago. And the U.S. really stepped up surveillance after the case was identified in Indiana.

“The most important thing (is) we've got to really get out in front of this, and we were doing that prior to this case being identified because we knew that it was likely to happen," Wells said.

MERS is a relatively new virus to humans and was first reported in Saudi Arabia in 2012.

[WATCH: Local doctor's thoughts on MERS]

The first MERS patient in the U.S. was also a healthcare worker at a hospital in Saudi Arabia's capital city. He flew to the United States on April 24. After landing in Chicago, the man took a bus to Munster, Indiana where he became sick and went to a hospital on April 28.
    
The man, an American, improved and was released from the hospital late last week. Tests of people who were around the man have all proved negative, health officials have said.
    
Details about the newest case were not immediately released Monday.
    
MERS belongs to the coronavirus family that includes the common cold and SARS, or severe acute respiratory syndrome, which caused some 800 deaths globally in 2003.
    
The MERS virus has been found in camels, but officials don't know how it is spreading to humans. It can spread from person to person, but officials believe that happens only after close contact. Not all those exposed to the virus become ill.

So far, all sickened had ties to the Middle East region or to people who traveled there.
    
The virus appears to be unusually lethal -- by some estimates, it has killed nearly a third of the people it sickened. That's a far higher percentage than seasonal flu or other routine infections. But it is not as contagious as flu, measles or other diseases. There is no vaccine or cure and there's no specific treatment except to relieve symptoms.

"We have sent additional staff to Saudi Arabia in conjunction with the World Health Organization to learn more about the virus, including to try to understand where it comes from and what are the risk factors for acquiring it," said Dr. Tom Frieden, director of the CDC.

Before entering the U.S., the virus spread to Europe and Malaysia.

Dr. Om Kapoor of the infectious disease department at Baptist Health said it's reason to be cautious but nothing to panic about.

"Once you get it or if you get exposed, it is a big concern because there is no treatment or vaccine for this," Kapoor said. "Mortality could be up to 30 percent. So it could be alarming if we don't use the caution right now."

Experts say don't go near sick people if at all possible. Wash your hands often and don't touch your eyes or mouth with your hands. If you have symptoms like fever, chills or cough, see a doctor.

“If you develop symptoms and you've had recent travel, then you should see your physician and trust that we in the public health system have pushed the information out to your clinician so they can do a full and thorough assessment,” Wells said. "Particularly in this case, with a virus we don't know everything about and as with most viruses we don't have medications to treat effectively, prevention is really the key."