Medical workers on Friday launched a month-long international hunt for additional coronavirus cases that could infect more people, as South Africa’s government said 10 new patients have become ill since last week.

Four were sent for further treatment with severe respiratory conditions and four were admitted to hospitals in Port Elizabeth, according to the statement by South Africa’s department of health. There is no treatment for coronavirus, but it can cause severe coughing, breathing difficulties and death.

The countries most at risk from Middle East Respiratory Syndrome, or MERS, are Saudi Arabia, Qatar, Jordan, Britain, Italy, Germany, France, Portugal, Tunisia and the United Arab Emirates. The only known outbreak of the virus has so far been in Saudi Arabia.

Last year, South Africa said that its government was setting up a tropical infectious diseases response center to develop protocols and response plans, as well as to operate a rapid diagnostic laboratory, a mobile laboratory, and a surveillance system for suspected cases.

Health officials had already been worried that the outbreak of MERS among some patients in Port Elizabeth and Rustenburg would spread to other places in South Africa. MERS broke out in the Middle East earlier this year, prompting the World Health Organization to declare a global health emergency.

More than 1,500 health care workers are in South Africa preparing for a large outbreak of MERS and have already completed more than 50 trainings on pandemic preparations and crisis management, the government said.

Also on Friday, South Africa’s Port Elizabeth province joined a growing list of places in the region taking voluntary measures to limit the spread of MERS and other viruses, including quarantining individuals suspected of having the disease or carrying the virus. Health workers have also stopped giving blood at the provincial hospitals.

The Port Elizabeth provincial health department said it had set up special care units for the 27- to 60-year-old group considered “highly susceptible” to spreading disease. The health minister, Aaron Motsoaledi, has appointed a special monitoring committee to oversee the emergency response.

Dr. Fielo Brown, the health department’s coordinator of disease control, said the recommendations were made on Thursday after a public meeting attended by more than 100 people in Port Elizabeth. Brown said the committee has decided on a series of measures, including the house quarantine for “high-risk patients.”

“I think it’s right to investigate, but you can’t be a human with it,” Brown said in an interview. “It’s really, really difficult to see where the next cluster of these infection is going to be,” he said.

While North America and Europe have escaped the MERS outbreak, Brown said it could come to Africa in the same way that Ebola and H1N1 viruses did.

“What we’re seeing here in this outbreak is very different to what we saw with Ebola,” he said. “People who have been exposed had to be diagnosed, treatment was done and we know where the people are.”

Brown said there were still many questions that should be answered before knowing whether the MERS outbreak was spreading among South Africans in South Africa or other parts of the world.

“This is also very different from the Ebola outbreak,” he said. “There was just the first identified case, and we all know how that went. This was not like the Ebola outbreak, where we saw several cases, and now it’s six months down the road and it’s still not clear who’s been exposed and how many cases have been happening, which is still very unclear, and still we’re looking.”