Thousands of South Korean schools that were shut to stop the spread of Middle East Respiratory Syndrome (MERS) reopened on Monday as the country sought to return to normal, nearly four weeks into an outbreak that shows signs of slowing.

Five new cases were reported by the Health Ministry on Monday, taking the total to 150, the largest outbreak outside of Saudi Arabia. The ministry also said another patient infected with the MERS virus had become the 16th fatality.

But the number of new cases was sharply lower than daily rises that reached as high as 23 last week. The World Health Organization (WHO) said on Saturday the decline suggested that control measures were working.

First identified in humans in 2012, MERS is caused by a coronavirus from the same family as the one that triggered China's deadly 2003 outbreak of Severe Acute Respiratory Syndrome (SARS). There is no cure or vaccine.

A hospital in Daejeon, 140 km (87 miles) south of Seoul, stopped taking all new patients on Monday as a precaution after a nurse there was among those diagnosed with the virus, the fifth hospital to have shut down completely or in part.

All of the cases in what the WHO called a "large and complex" outbreak have been traced to healthcare facilities.

At least 440 schools remained closed on Monday, compared with the 2,900 that were shut on Friday.

South Korean President Park Geun-hye, whose approval rating has been battered over the government's response to MERS, urged people to return to normal.

"I ask the business community, too, to continue to go on with investment, production and management activities as normal and particularly help with ensuring that consumers don't hold back from spending money," she told senior aides.

The Health Ministry said it would quarantine or put under observation about 4,000 people who may have been exposed to MERS at a prominent Seoul hospital, the Samsung Medical Center, which has suspended most services.

But many in that group are among the 5,216 already under quarantine, most of them at home and some in hospitals.

INCUBATION PERIOD

The Samsung hospital said on Sunday it was suspending all non-emergency surgery and would take no new patients after more than 70 cases were traced to it, including a worker who was found to have been in contact with more than 200 people.

Deputy Prime Minister Choi Kyung-hwan told parliament that the next two days would be a watershed period for the outbreak, as the two-week incubation period for the initial wave of cases traced to the Samsung hospital comes to an end.

Choi, who is also the finance minister, said the government was considering a possible supplementary budget to bolster the economy, Asia's fourth-biggest.

At Myoungin Elementary School in the city of Suwon, south of Seoul, teachers greeted students at the gate for the first time in 10 days, taking temperatures and sending home anyone with a fever.

The WHO last week recommended schools be reopened, saying they have not been linked to transmission of the virus in South Korea or elsewhere.

"The child's mother and I both work, so I think it's better for kids to be in school where there can be proper measures, rather than keeping them home," said Bin Ko-ok, who brought her first-grader grandchild to school.

South Korea said more than 110,000 group tourists had called off visits since the start of the outbreak, and forecast that from June through August 820,000 fewer people would visit, at a cost of $900 million in lost potential revenue.

The trend is expected to continue through the summer, the culture ministry said. Chinese airlines were cutting back flight to South Korea, Xinhua news agency reported.

South Korea's largest hypermarket chain, E-Mart Co Ltd, said online sales between June 1-11 had risen 63 percent year-on-year, as people avoided stores, while No.2 Homeplus's online sales between June 1-14 rose 50 percent.