Written by Steve McAnon, CNN
"What we know today is that we have a global threat. And we now know that it is a threat that is in motion," Anthony Fauci, director of the National Institute for Allergy and Infectious Diseases, told CNN's Christiane Amanpour on Monday.
"We have the coronavirus as a global threat," he said, adding that the virus is transmissible between humans.
"But to be able to explain precisely where this virus is transmittable, where the other viruses are transmittable, and how they interact with the virus ... we don't really know yet. That's the important work that is to be done."
World Health Organization deputy director general Keiji Fukuda spoke later in the day.
"This is a new kind of disease and, although we are seeing one more case of infection, we still don't know exactly how it works, how it spreads among humans. We are collecting information daily, and we're following up on contacts and contacts of contacts, but it's early to tell at this point. So we know it is an unusual kind of virus."
Fauci's comments came during an interview on "The Situation Room" Monday evening.
The number of infections from the new virus has remained at about 2,700 since the first case was reported more than a year ago, Fauci said.
"We still don't know exactly how this virus works," he said. "We still don't know exactly how it spreads among humans."
But the World Health Organization said Monday it remains very concerned about the threat posed by the new coronavirus, known as MERS-CoV.
In a press release, the WHO said the infection in France has been confirmed to be the 16th case reported in the world in the past 12 months, as the agency's specialist response team meets this week to assess its handling of the outbreak.
"The expertise that we have, that we have assembled, that our experiences have been building on all over the last decade, will really be the distinguishing factor for the way we work in this outbreak," said Fauci, speaking in the same briefing room as Fukuda.
Since May, the MERS virus has killed about 47% of those infected, the press release said. The first confirmed case was in Saudi Arabia.
MERS-CoV can cause severe respiratory illness and kidney failure. Symptoms can range from fever, cough and shortness of breath to coughing, pneumonia and pneumonia with blood in mucus, the WHO says.
An estimated 680 million people, or about 1 in 25, live in areas of heightened risk from MERS, the organization said.
In an interview with CNN Tuesday, Fauci said the high percentage of deaths from MERS is simply a result of mortality rates in general among viruses.
"That isn't going to affect us much. We don't really have a vaccine for this virus. We don't have a treatment for this virus," he said.
"So we are not looking for a cure right now. We're looking for control and that's been our goal from the beginning."
MERS-CoV has been reported in 15 countries and health authorities believe there may be at least one source for human-to-human transmission of the virus, the WHO says.
In addition to Saudi Arabia, the virus has been reported in Afghanistan, Bahrain, Egypt, France, Germany, Greece, Jordan, Kuwait, Lebanon, Morocco, Oman, Qatar, Saudi Arabia, Senegal, South Korea, Spain, Tunisia and the United Arab Emirates.