The situation in South Korea has alarmed the global health community because the virus has spread so fast and wide from a single individual. Other countries have imported cases in the same manner but the virus infected only a few others.
How did MERS get to South Korea and why is it spreading so fast?
The first known case, called an “index” case, was reported on May 20. It involved a 68-year-old man who was returning from a 16-day business trip to four Middle Eastern countries. The man was asymptomatic during his return flight but was subsequently treated at two different out-patient clinics and two hospitals which created a lot of opportunities for the virus to spread. Health care workers did not suspect the man of having MERS so he was not put in isolation.
Others who have been infected include health care workers, other patients, family members and visitors. The World Health Organization reported that some of the cases were patients in the same room or ward as the man, and that their exposure may have been from 5 minutes to a few hours.
Two recent cases represent an alarming development —a third generation of transmission. That is, a patient who did not have contact with the index patient but came into contact with an intermediary who had been exposed to the virus. "That raised fears that infections could now spread exponentially from all people who test positive," Korea's JoongAng Daily reported.
Most of the primary schools that were shut down are in Gyeonggi province which surrounds the capital of Seoul and where many of the cases have been.
Peter Ben Embarek, a World Health Organization working on MERS, told Science magazine that the simplest explanation for the "superspreading" event of the virus in South Korea may be a lapse in infection control measures at the hospital. It's also possible the strain that was imported may be different from others or that Koreans are more susceptible to the disease.
The South Korean government has come under criticism for their handling of the situation, including its refusal to disclose the names of the health care facilities where the first patient was treated.