Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus (MERS-CoV). It was first identified in Saudi Arabia in September 2012 after the death of a local businessman in Jeddah. Retrospective investigation has identified the first known cases of MERS-CoV occurred in Jordan in April 2012.1
Coronaviruses are a large family of viruses. They cause a range of diseases, including the common cold and severe acute respiratory syndrome (SARS), which caused a global alert in 2003 and resulted in over 8000 cases.2
Initially MERS-CoV was thought to involve bats, like the Nipah virus where a bat to pig to human transmission cycle is seen. However, MERS-CoV identical to human strains have been isolated from camels in Egypt, Oman, Qatar and Saudi Arabia, and the virus is now believed to have been transmitted from bats to camels in the distant past.
The virus appears to be circulating throughout the Arabian Peninsula. Although more than 85% of cases have been reported in Saudi Arabia, several cases have been reported outside the Middle East (Box 1). Most of these infections, including the current outbreak in South Korea, are believed to have been acquired in the Middle East and then exported outside the region.3