Middle East respiratory syndrome (MERS): A new zoonotic viral pneumonia

Cunha, Cheston B; Opal, Steven M

Coronaviruses have worldwide distribution and previously were associated with mild upper respiratory tract infections, e.g., the common cold is caused by coronavirus types 229E and OC 43. 1 From Guangdong Province in southern China in the fall of 2002, a new coronavirus emerged causing severe viral pneumonia, i.e., severe acute respiratory syndrome (SARS). This new coronavirus variant was termed SARS-CoV. The intermediate host of SARS-CoV was the masked palm civet cat. 2 From China this new zoonotic viral pneumonia rapidly spread worldwide to 30 countries. In one year, 8273 SARS cases occurred with 774 deaths. In addition, the financial impact from limiting travel, tourism, disruption of trade and commerce, shifting of hospital services, quarantine of exposed patients and health care workers, and lost wages suffered from victims of SARS, isolation of patients suspected of carrying the contagious virus was enormous. Mutation of SARS-CoV surface spike proteins found in the coronavirus that usually circulates in the animal reservoir permitted binding to human ACE 2 receptors with a sudden switch in susceptible vertebrate hosts facilitating transmission to humans. 1, 2 As mysteriously as SARS appeared in 2002, it disappeared in the summer of 2003.