WHO map of MERS cases by country. Click to enlarge.

By Betsy Todd, MPH, RN, CIC, AJN clinical editor

Middle East respiratory syndrome (MERS) first emerged in Saudi Arabia in September 2012. Until last month, most MERS cases have occurred in that country. But on May 20, South Korea reported its first laboratory-confirmed case of MERS, in a 68-year-old man who had recently returned from a business trip to the Middle East.

The diagnosis was made only after the man had visited four health care facilities since his return home. This resulted in nosocomial transmission to other patients, health care workers, and visitors. To date, the Republic of Korea’s Ministry of Health has identified 108 cases of MERS in South Korea. Nine patients (all with serious preexisting health conditions) have died.

The WHO notes that all of these cases are epidemiologically linked to the index case. That is, there is no evidence that a new “reservoir” of MERS virus has suddenly surfaced in South Korea—all cases thus far stem from the Korean traveler who acquired his infection while visiting the Arabian Peninsula.

This is the largest outbreak of MERS so far outside of the Middle East, and therefore a reason for some concern. However, person-to-person transmission of MERS is not new, and there has as yet been […]