LONDON (AP) -- International health officials have confirmed two more fatal cases of a mysterious respiratory virus in the Middle East.

The virus has so far sickened nine people and killed five of them. The new disease is a coronavirus related to SARS, which killed some 800 people in a global epidemic in 2003, and belongs to a family of viruses that most often causes the common cold.

The two cases date back to April and are part of a cluster of a dozen people, mostly health workers, who fell sick in an intensive care unit at a hospital in Zarqa, Jordan. Officials are investigating whether the 10 other people who grew sick in Zarqa also were infected and how the virus might have spread.

"It's too early to say whether human-to-human transmission occurred or not, but we certainly can't rule it out," said WHO spokesman Gregory Hartl.

One of the Jordanian cases was a 40-year-old female. All of the other patients to date have been men. The new virus has so far been identified in patients from Saudi Arabia and Qatar.

Scientists haven't found any links between the sporadic cases of the coronavirus so far, first detected in September. "We don't know how the virus gets around and there are more questions than answers right now," Hartl said.

Several of the patients sickened by the new coronavirus have had rapid kidney failure and others have suffered severe pneumonia and respiratory illnesses. The virus is most closely related to a bat virus and scientists are also considering whether bats or animals like camels or goats are a possible source of infection.

Scientists are also considering whether fruit contaminated by animal droppings may have spread the virus.

Still, not all of the cases had contact with animals and WHO said it was possible the virus was spread between humans in the Jordan hospital and in a cluster of cases in Saudi Arabia, where four members of the same family fell ill and two died.

WHO says the virus is probably more widespread than just the Middle East and recommended that countries test any people with unexplained pneumonia.

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