WHO calls MERS outbreak a 'wake-up' call

“We really don't understand the situation very well,” said Dr. Keiji Fukuda, a WHO assistant director-general, noting it was unclear if the disease could be spread by people without symptoms or what environmental factors might speed transmission.

MERS is caused by a coronavirus from the same family as the one that triggered China's deadly 2003 outbreak of severe acute respiratory syndrome (SARS). Fukuda said camels are the only known animal reservoir for the disease, although there could be others. He added there was no proof MERS had mutated into a more dangerous form in South Korea, where 19 people have died.

Overall worldwide, 458 people have died from MERS since 2012, with most infections and deaths occurring in Saudi Arabia. A total of 162 people have been infected in South Korea, with eight individuals added to that list on Wednesday.

The only east Asian outbreak thus far has been traced to a 68-year-old South Korean man who returned from a business trip to the Middle East in early May, and the WHO said it expected new cases in coming weeks, although the numbers appear to be declining.

The eight new South Korean cases marked a rise from the four and five the previous two days, but below double-digit daily increases reported last week.

“It is absolutely critical to keep high-level surveillance, keep up high levels of monitoring,” Fukuda told a briefing in Geneva.

More than 6,500 people are in quarantine in South Korea, either at home or in health facilities.

WHO recommends that people avoid contact with camels, not drink camel milk and only eat camel meat that has been well-cooked.

MERS appear to be spread among people in respiratory droplets such as by coughing, although infections have mostly occurred in those who had close contact with MERS patients. More than two-dozen countries have reported cases, including the U.S., Britain, France and Germany.

Some experts lamented that little had changed in WHO's ability to respond to outbreaks since last year's devastating Ebola outbreak in West Africa, which left more than 11,000 dead still hasn't been fully contained.

“I don't understand why they have not prioritized developing a camel vaccine to stop transmission from young camels to humans,” said Michael Osterholm, an infectious diseases expert at the University of Minnesota.

“If MERS shows up in the inner cities of one of the developing world megacities, like Lagos or Kinshasa, we will be in real trouble,” he said. “We know there will be future outbreaks if MERS isn't stopped in the Middle East, but we are not very close to doing that now.”

Wire services