British officials alerted WHO on Saturday of the new virus in a man transferred from Qatar for treatment in London. He had recently traveled to Saudi Arabia, where another man died of a similar illness earlier this year.
The man in the new case was sickened by a coronavirus, from a family of viruses which causes most common colds but also includes the virus that causes SARS, or severe acute respiratory syndrome. In 2003, SARS killed some 800 people, mostly in Asia, in a short-lived epidemic.
"It's still very early days," said Gregory Hartl, a WHO spokesman. "At the moment we have two sporadic cases and there are still a lot of holes to be filled in." Hartl said it was unclear how the virus is spread and there was no evidence of human-to-human transmission.
Coronaviruses are typically spread in the air but Hartl said scientists were considering the possibility that patients were infected directly by animals. "All possible avenues of infection are being explored right now," he said.
So far there is no connection between the cases except for a history of travel in Saudi Arabia. SARS was first spread to humans from civet cats in China.
Hartl said no other countries have so far reported any similar cases to WHO.