A nurse moves a man (C), suspected of carrying MERS virus, at the Samsung Medical Centre in Seoul, on June 8, 2015
South Korea recorded its sixth death and biggest single-day jump in Middle East Respiratory Syndrome (MERS) infections Monday, with 23 new cases in the largest outbreak of the potentially deadly virus outside Saudi Arabia.
From just four cases two weeks ago, the total number of infections now stands at 87, including six people who have died.
The latest fatality was an 80-year-old man who died Monday morning in a hospital in Daejeon, 140 kilometres (87 miles) south of Seoul, the health ministry said.
The outbreak has triggered widespread public concern in South Korea, with 2,500 people placed under quarantine orders and nearly 2,000 schools -- mostly in Seoul and surrounding Gyeonggi province -- closed down.
But experts say the likelihood of a serious epidemic is remote, given that the MERS virus is not easily transmitted person-to-person.
"The chance of a massive outbreak in South Korea is not high," said Ho Pak-leung, a microbiology expert at the University of Hong Kong.
"Rather I think there will be continued transmissions at a low level," Ho told AFP.
Among the new cases announced Monday, most were infected at the Samsung Medical Centre in southern Seoul -- one of the country's largest hospitals where nearly 900 patients and staff have now been placed under observation.
- First teenage case -
A 16-year-old student became the first teenage case, but the education ministry stressed he had contracted the virus while already in hospital, so it was "not possible" that he had infected any classmates at school.
All the infections so far have been restricted to hospitals.
Criticised for its initial response to the outbreak, the government on Sunday vowed "all-out" efforts to curb the further spread of the virus, including tracking the mobile phones of those under house quarantine to ensure they stay home.
Several have already been caught sneaking out, despite facing possible fines of three million won ($2,670).
Chung Eun-Kyung, a senior official at the Korea Centre for Disease Control and Prevention, said those confined to their homes should stay alone in a room and wear a surgical mask when interacting with family members.
Hundreds of public events, school trips and sporting fixtures have been cancelled, with movie theatres, theme parks and shopping malls reporting big drops in the number of customers.
Ticket sales at movie theatres fell to 2.46 million for the first week of June, down from 3.85 million a week earlier, according to the Korea Film Council.
- Emptying supermarkets -
Both E-Mart and Lotte Mart, two of the country's biggest supermarket chains, reported a 12 percent drop in weekly store sales, coupled with a 50 percent surge in online sales.
Those who did venture to the stores were greeted by staff who wiped down the handles of the supermarket trolleys before and after use.
Schools that remained open screened students arriving for class Monday morning, checking their temperature with an ear thermometer at the gate and sending home anyone with even a mild fever.
Lee Hyun-Shil, who was taking her son to a kindergarten in Seoul, said she was in "utter shock" over the scale of the outbreak.
"I can't believe this is happening in South Korea," Lee told AFP.
"I am really worried these days... and wonder if it's OK to use a subway to go somewhere," she said.
Hong Kong University's Ho said the South Korean authorities had erred in initially refusing to name the hospitals where MERS patients had been treated.
"If you are not transparent in terms of what happened, people will start to lose trust, and there will be unnecessary fear and rumours.
"That makes any effort to try to contain it much more difficult," he said.
More than 20 countries have been affected by MERS, with most cases in Saudi Arabia.
The virus is considered a deadlier but less infectious cousin of Severe Acute Respiratory Syndrome (SARS), which killed hundreds of people when it appeared in Asia in 2003.
A team of officials from the World Health Organization arrived in Seoul on Monday to help investigate the outbreak and offer advice on its containment.