Coronaviruses, named for the crown-like spikes on their surface, are common viruses that most people around the world get some time in their life. Human coronaviruses usually cause mild to moderate upper-respiratory tract illnesses.
A novel coronavirus now called "Middle East Respiratory Syndrome Coronavirus” (MERS-CoV) was identified in 2012 as the cause of respiratory illness in people causing fever, cough, and shortness of breath. Globally, from September 2012 to May 12, the World Health Organization (WHO) has been informed of a total of 536 laboratory-confirmed cases of infection with MERS-CoV; 145 have died.
According to the US Centers for Disease Control and Prevention (CDC), so far, all the cases have been linked to countries in the Arabian Peninsula. This virus has spread from ill people to others through close contact, such as caring for or living with an infected person. However, there is no evidence of sustained spreading in community settings.
On May 2, 2014, the first U.S. case of MERS was confirmed in a traveler from Saudi Arabia to the U.S. The traveler is considered to be fully recovered and has been released from the hospital. Public health officials have contacted healthcare workers, family members, and travelers who had close contact with the patient. At this time, none of these contacts has had evidence of being infected with MERS-CoV.
On May 11, 2014, a second U.S. imported case of MERS was confirmed in a traveler who also came to the U.S. from Saudi Arabia. This patient is currently hospitalized and doing well. People who had close contact with this patient are being contacted. 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.
Thus far, all human-to-human transmission has occurred either in a household, work environment, or health care setting. While the mode of transmission currently remains unknown, in some cases, the virus appears to pass from an infected person to another person in close contact.
The full picture on the source of the infection also is not yet clear. Strains of MERS‐CoV that match human strains have been isolated from camels in Egypt, Qatar, and Saudi Arabia. These and other studies have found MERS‐CoV antibodies in camels across Africa and the Middle East.
MERS-CoV infection generally presents as pneumonia, but has also caused kidney failure. The most common symptoms observed are fever, cough, and breathing difficulties, while atypical symptoms such as diarrhea have also been recorded in patients with immunosuppression.