Health investigators and scientists are stepping up their investigation of the Middle East Respiratory Syndrome virus after it spread from person to person in the U.S. The virus has spread from the middle east and can be transmitted through person to person contact.

Meanwhile, Transportation Security Administration officials, at the request of the U.S. Centers for Disease Control and Prevention, are posting Middle East Respiratory Syndrome warning signs at 22 major U.S. airports, including O'Hare, after two cases of the virus have been reported in patients who traveled to Saudi Arabia.

Middle East Respiratory Syndrome (MERS) is viral respiratory illness first reported in Saudi Arabia in 2012. It is caused by a coronavirus called MERS-CoV. Most people who have been confirmed to have MERS-CoV infection developed severe acute respiratory illness. They had fever, cough, and shortness of breath. About 30% of these people died.

In May, 2014, the first U.S. imported case of MERS was confirmed in a traveler from Saudi Arabia to the U.S. On May 11, 2014, a second U.S. imported case of MERS was confirmed in a traveler who also came from Saudi Arabia. The two U.S. cases are not linked. On May 16, 2014, an Illinois resident who had contact with the first case of MERS in the U.S. tested positive for MERS-CoV.