MERS virus didn’t morph in its move to South Korea

No obvious changes in the MERS virus account for its rapid spread in South Korea, a report by the World Health Organization says.

Researchers in South Korea analyzed the genetic makeup of the Middle East respiratory syndrome, or MERS, coronavirus from a traveler who was infected on a business trip to the Middle East. The man fell ill after he returned to South Korea and set off an outbreak that has sickened at least 87 people and killed six.

One of the people who may have caught the virus from the traveler broke quarantine and traveled to China. Chinese authorities placed him in isolation and the Chinese CDC determined the genetic makeup of his MERS virus. There are 22 DNA differences between the viruses from the two men. Those differences are probably due to technical problems, the report says.

The viruses are similar to those from an outbreak in Riyadh, Saudi Arabia, earlier this year. But the MERS viruses from the Chinese and Korean patients are different enough from the Riyadh viruses that the Asian forms could have stemmed from the traveler encountering an infected bat or camel, instead of catching the virus from a person. The traveler had no known exposure to animals.

The viruses from the two men don’t share changes in proteins that would explain the quick person-to-person spread in hospitals in South Korea.