The World Health Organisation is investigating the emergence of a new SARs-like virus, which has killed one man and left another fighting for his life.
The virus, known as a coronavirus, comes from the same family as SARS which emerged in 2002 and killed 800 people, but the WHO says the virus is different than any previously found in humans.
"It's a coronavirus, it's a new coronavirus, and it's a virus which causes pneumonia and pretty rapid kidney failure. We don't know how many cases there have been so far because what happens in a health system normally is only something out of the ordinary, something severe gets notified. so we've had three severe cases notified to us. One which will never be tested because the person died before he could be tested and two cases which have been tested and are positive for this new virus," WHO spokesperson Gregory Hartl told Reuters TV in Geneva.
The U.N. health body put out a global alert on Sunday (September 23) saying a new virus had infected the 49-year-old man who had recently travelled to Saudi Arabia - where another man with an almost identical virus had already died.
"Well again it's only two cases so far, so one of the things we need is more information, we need more information on is this really only two cases or is it the tip of an iceberg. We don't know. Is it the fact that all cases of this new virus are severe or are only a small percentage severe and that there is a lot of mild cases that don't get reported, these kind of things, we don't know," Gregory Hartl said.
The Qatari man first showed symptoms of an acute respiratory infection while he was in Qatar. He spent some time in intensive case in Qatar and was later flown to the UK where he is currently in a London hospital's intensive care unit, being treated for acute respiratory infection and kidney failure.
The WHO said it was investigating how the new virus was transmitted, but declined any human link between the two cases, since the first case was found three months earlier than that of the Qatari man currently in a critical state.
"We don't know if it's going to kill a lot of people or if this is just a virus which will pop up on occasion and then disappear again, we don't know how it's transmitted yet even, if it transmits from person to person or from animal to human, so until we understand things like that, we can't make any kind of judgement on as to how widespread it might be, how deadly it might be, it's too early", Gregory Hartl said.
Coronaviruses are a large family of viruses that includes causes of the common cold but can also include more severe illness such as the virus responsible for SARS.
SARS, or Severe Acute Respiratory Syndrome, appeared in China in 2002 and infected more than 8,000 people worldwide, killing around 800 of them before being brought under control.