More than 3,000 people are in quarantine in South Korea amid an outbreak of Middle East Respiratory Syndrome (Mers), which by Friday had killed four people.
South Korean officials confirmed five new cases of the virus, bringing the total confirmed cases to 41, and promised to do all it could to stop it spreading.
The outbreak is the largest outside of Saudi Arabia where the disease first appeared in 2012, the BBC reported. Mers has killed 440 people since then.
Sales of surgical masks have soared and more than 1,160 schools and nurseries have been shut. There are 70 camels, which are believed to spread the disease, in zoos that are also in quarantine.
Medical officials have so far advised more than 3,000 people to stay at home in voluntary quarantine, or have been quarantined in medical facilities.
Criticism of President Park Geun-hye has also begun to spread. He has been accused of not doing enough to contain the outbreak, the New York Times reported.
The mayor of Seoul, Park Won-soon, voiced concern on Thursday that the government had withheld the fact that a doctor who had contracted the virus had attended an event along with 1,500 others, despite having been quarantined.
The outbreak can be traced to a 68-year-old man who travelled to the Saudi Arabia and the United Arab Emirates and was exposed to the virus.
He went to a number of hospitals, “creating multiple opportunities for exposure among health care workers and other patients,” the World Health Organization (WHO) said this week.
Doctors did not initially recognise his symptoms as those of Mers, which has an incubation period of five to six days and causes fever, cough and shortness of breath.
As it progresses, it can cause pneumonia and kidney failure and has a mortality rate of around 38 per cent, according the WHO. It is more deadly than Sarseditorial but not spread as easily.
Despite widespread panic in the country, most of the cases are contained to six hospitals in the Gyeonggi Province surrounding Seoul. Those infected include, the New York Times said, staff members, patients and visitors to the hospitals.
The most recent Mers patient to die was a 76-year-old man who had been in the same ward as other Mers patients and had been suffering from various ailments including cancer, the Health Ministry said.
North Korea reportedly asked the South Korean government to borrow heat-detecting cameras to screen factory managers that work in a border town.
By Friday, the WHO had not recommended travel restrictions but thousands of people had already cancelled flights from China, Hong Kong and Taiwan. Airlines have announced extra sanitising measures.
Additional reporting by ReutersReuse content