By Alex Jensen

SEOUL

South Korea’s MERS death toll is continuing to rise along with the number of people infected in the country from the often-fatal respiratory disease.

As of Friday, more than 1,500 people are feared to have made contact with a doctor who tested positive a day earlier.

The health ministry said Friday that the number of cases in the past week has more than doubled to 41, and confirmed that the outbreak had claimed a fourth victim - a 76-year-old man who was among the first to test positive for Middle East Respiratory Syndrome, on May 21.

All four deaths so far have occurred since Monday, raising concerns about the lag between infection, symptoms, and either recovery or death.

Local authorities were expected to confirm later in the day whether or not they were dealing with a mutation.

It was still unclear whether South Korea’s outbreak would prove to be as devastating as elsewhere - MERS has a fatality rate of more than 40 percent based on around 1,150 infections worldwide.

Like the still-feared SARS before it, MERS is caused by a strain of coronavirus - but it only emerged three years ago in Saudi Arabia and there is no known cure or vaccine.

The source of the outbreak was a man returning from a trip to the Middle East last month.

Following an initially “insufficient” response, by President Park Geun-hye’s own admission, over 1,600 people had been placed in isolation by Thursday.

Quarantine measures could be extended further, however, after Seoul Mayor Park Won-soon broke with central government protocol when he revealed that an infected doctor may have exposed many more members of the public.

The medic in question attended a series of meetings at the end of last month before testing positive - including one gathering attended by nearly 1,600 people in the capital.

After the mayor insisted that he would “devise the city’s own countermeasures to protect citizens,” Health Minister Moon Hyung-pyo hit back at Park at a separate briefing Friday.

“I deeply regret it that the Seoul city government has caused unnecessary public misunderstanding and concerns with its unilateral claims that made it look as if government measures to stop the spread of the disease are wrong,” Moon told reporters.

Of further concern was the confirmation that an Air Force chief master sergeant had also been infected, becoming the country’s first military case - a particular worry given the close living and working conditions in the forces.

Meanwhile, well over 1,000 schools were closed with more following suit in an effort to protect students.