In 2013, the U.S. Centers for Disease Control and Prevention (CDC) activated its Emergency Operations Center to investigate a novel coronavirus, Middle East Respiratory Syndrome Coronavirus, or MERS-CoV.

As of Jun. 7, 2013, a total of 55 laboratory-confirmed cases had been reported to the World Health Organization (WHO). Illness onsets occurred during April 2012 through May 29, 2013. All reported cases were directly or indirectly linked to one of four countries: Saudi Arabia, Qatar, Jordan, and the United Arab Emirates.