Middle Eastern Respiratory Syndrome (MERS) may slowly be spreading in the U.S., as two health care workers were exposed to a patient with it.

According to NBC News, the health care workers in Orlando were in contact with the second person in the U.S. to be diagnosed with MERS. One is not likely to have contracted the virus and was sent home and the other is in isolated care like the patient.

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

The Florida patient is a 44-year-old Saudi Arabia health care worker visiting family in Orlando when he was admitted to the emergency room May 8. As many as 20 workers in two area hospitals may have been exposed, but the two are the ones who showed symptoms.

MERS was first identified in 2012 and 500 people in 16 countries, mostly in Saudi Arabia, have since been infected. MERS has killed about a quarter of its patients. With both the Florida patient and the one in Indiana, the first confirmed MERS case in the U.S., the general public is not at any risk. Health care workers are the most at risk since they are in close contact.

According to the Chicago Tribune, President Obama has been briefed on both patients.

"The president has been briefed on this development," White House spokesman Jay Carney told reporters. "The CDC (U.S. Centers for Disease Control and Prevention) is taking the current situation very seriously and is working in close coordination with local health authorities."

MERS is similar to SARS and causes coughing, fever and potentially fatal pneumonia. However, SARS killed more than 800 people in 2002 when it was first discovered in China.

MERS originated with bats in Saudi Arabia, who likely infected camels, who then passed the virus to humans. There is not yet a vaccine for MERS.