“Middle East Respiratory Syndrome” has popped up in South Korea.

A deadly virus with no known cure — Middle East Respiratory Syndrome, or MERS — has infected 13 people in South Korea since mid-May. The fast spread of the disease, from the first case confirmed on May 20 to more than a dozen by Saturday, is prompting criticism of health officials for not moving faster to quarantine suspected patients…

MERS is from the same family as the virus that triggered China’s 2003 outbreak of Severe Acute Respiratory Syndrome, or SARS. Scientists first identified it in 2012, and since then, more than 1,100 cases have been reported in 23 countries, with the bulk majority of cases occurring in the Middle East.

So far, not only is there no known cure, there’s no vaccine to prevent it, either.