South Korea announced its 20th death from the MERS virus Wednesday as criticism grew over authorities’ ability to contain the outbreak.

South Korea announced its 20th death from the MERS virus Wednesday as criticism grew over authorities' ability to contain the outbreak, with alarming reports of new cases slipping through a quarantine that already affects thousands.

A 54-year-old woman died of Middle East Respiratory Syndrome Wednesday morning, about two weeks after being diagnosed on June 5, the health ministry said.

It also reported eight new patients -- including four who had been infected in Samsung Medical Centre in Seoul, considered the epicenter of the outbreak -- a day after the ministry said it was cautiously optimistic that the worst was over as the number of new cases appeared to be falling.

Almost all infections so far have been limited within hospitals.
But several new patients diagnosed in recent days were not among those placed under quarantine.

The number of people who were exposed to patients and placed under quarantine -- either at state facilities or at home -- jumped by 922 to more than 6,500 people, the ministry said Wednesday.

A total of 19 people have recovered and were released from hospital, it added.
The virus appeared in South Korea on May 20 when a 68-year-old man was diagnosed after returning from a trip to Saudi Arabia.

Since then it has spread at an unusually rapid pace, sparking widespread public alarm over what has become the largest outbreak outside Saudi Arabia.

On Tuesday, the health ministry said the number of new cases had gradually declining from 12 on Friday to four that day, sparking hope the outbreak might be showing signs of easing.

There is no vaccine for MERS which has a mortality rate of 35 percent, according to the WHO.
In Saudi Arabia, more than 950 people have been infected and 412 died of the virus.