Now a virus that has caused respiratory failure and 30 deaths has turned up in Italy.

The World Health Organization says lab tests have confirmed the infections in a 2-year-old girl and a 42-year-old woman with the Middle East Respiratory Syndrome Coronavirus, or MERS-CoV, as it's now called.

Both of the patients, who are in stable condition, are close contacts of someone who traveled to Jordan recently, the WHO says.

Illnesses caused by the virus have originated in Jordan, Qatar, Saudi Arabia, and the United Arab Emirates, WHO says. In France, Germany, Italy, Tunisia and the United Kingdom, there have been additional cases seen in people who had traveled in the Middle East or who'd been in close contact with someone who had.

All told, there have been 53 cases where lab tests have showed conclusively that the virus was to blame, WHO says.

A recent French report on two cases (one involving a man who had traveled to Dubai and the other in a man who shared his hospital room) indicates that the incubation period for the virus may be as long as nine to 12 days, rather than one to nine days. That suggests that any quarantine of infected people may have to be prolonged to limit the spread of the virus.

WHO says doctors and hospitals should take care to prevent the spread of MERS-CoV by observing infection prevention and control measures.

Dr. Margaret Chan, WHO's director-general, recently called the virus "a threat to the entire world." Why? "We understand too little about this virus when viewed against the magnitude of its potential threat," she said. "Any new disease that is emerging faster than our understanding is never under control."

Although the coronavirus remains mysterious, there are some clues about its origin. An analysis of its genetic material last September found that it most closely resembled coronaviruses known to infect bats in Southeast Asia.

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