DUBAI, United Arab Emirates - A recent spate of infections from a frequently deadly Middle East virus is raising new worries about efforts to contain the illness, with infectious disease experts urging greater vigilance in combatting its spread.
More than 20 people, many of them health-care workers, have been reported infected with the Middle East respiratory syndrome coronavirus in two distinct clusters -- one in Saudi Arabia and the United Arab Emirates -- likely involving human-to-human transmission since early last week.
The disease, originally identified in 2012 in the Middle East, has also for the first time spread to the Far East, which grappled with an outbreak of the related SARS virus last decade.
"The last two weeks have put us into uncharted territory," said Michael Osterholm, an infectious disease expert at the University of Minnesota.
He described the recent batches of Saudi and UAE infections as "very important" and a possible signal that the virus could be mutating.
The disease's spread to Southeast Asia -- confined for now to people with clear links to the Mideast -- meanwhile "heightens the concern that we could be in the early days of another SARS-like event," he warned.
"We're clearly at a very significant stay-tuned moment," Osterholm said.
MERS belongs to a family of viruses known as coronaviruses that include both the common cold and SARS, or severe acute respiratory syndrome, which killed some 800 people in a global outbreak in 2003.
MERS can cause symptoms such as fever, breathing problems, pneumonia and kidney failure.
It does not for now appear to spread as quickly between people as SARS did. But it does seem to be more deadly. According to the World Health Organization, 92 of the 238 people confirmed to have been infected with MERS have died.
The WHO has stopped short of calling for specific travel and trade restrictions. It has urged member countries to report detailed information about all cases and says more needs to be known about how the disease is transmitted within hospitals.
A Malaysian man this week became the first person to die from the MERS in Asia. The 54 year old from southern Johor state, near Singapore, developed a high fever and cough and had difficulty breathing after returning from a pilgrimage in Saudi Arabia on March 29.
Scientists believe that camels are a key source of transmission of the virus to humans, though it is not clear how infection occurs.
It is also unclear how readily the virus can pass between people, though that appears to have happened in the Saudi and UAE infections.
"It is always a worry if sustained human-to-human transmission of a newly identified virus occurs," said Ian Mackay, a virologist affiliated with the Australian Infectious Diseases Research Center at the University of Queensland.
He noted that sustained transmission beyond those local clusters hasn't been seen yet, and that recent infections might have resulted from relatively close contact between medical professionals and an infected patient.
Other Mideast countries that have past reported cases of infection include Jordan, Kuwait, Oman and Qatar. A small number of cases have been diagnosed in Europe and North Africa.
Saudi health authorities last week reported that 11 people in the Red Sea city of Jiddah were infected, some of them health care workers, and that two had died.
Officials there took the extraordinary step of redirecting patients away from the King Fahd hospital, where at least one of those infected worked, to other health care facilities so the emergency ward could be thoroughly cleaned.
In an updated statement released Wednesday, the Saudi Health Ministry reported that 37 cases of the virus have been detected at five hospitals in Jiddah between March 15 and this past Tuesday, seven of them fatal.
It did not provide details, making it impossible to determine if there has been an increase in transmission rates. Officials could not be reached for clarification.
"We can only hope that the current hot zone, the Kingdom of Saudi Arabia, soon gets ahead of the outbreak through proactive action," Mackay said. "It seems that infection prevention and control has broken down in these health care outbreaks and this will need to be addressed throughout the region."
The United Arab Emirates separately reported infections among 10 health care workers linked to a Filipino paramedic who died in the Gulf country on April 10. According to information reported to the WHO this week, they range in age from 27 to 48 and were listed in stable condition. Most were hospitalized with no symptoms or mild illness. One showed signs of pneumonia.
The Philippines health department on Thursday urged all passengers who arrived on an Etihad Airways flight from the Emirati capital Abu Dhabi to Manila earlier in the week to seek testing after officials determined that one person on the plane was found to be infected. He is now being confined to the hospital, and family and friends are also being tested.
Abu Dhabi-based Etihad said health authorities in the Emirates are also contacting passengers who were on the flight, and that it is screening crew members who were onboard.