This is the CBS evening news with Nora O'Donnell, reporting from the nation's capital.

Good evening, Nora's off tonight. I'm Maurice Tobuoy, and we're going to begin here with the outbreak of a mystery virus in China that has now spread, and the World Health Organization is on edge.

At least four people have died and hundreds

more are sick, though there are concerns five times as many people could be infected.

Tonight, Chinese health officials say the illness, which is a new strain of coronavirus,

can be passed from person to person, stoking fears that it could be moving faster than it can

be contained. Extra health screening has been ordered at airports in China, as well as at airports across the U.S.

Experts say the virus started in the Chinese city of Wuhan, but it is now spreading across Asia.

Rami Innocentio leads off our coverage tonight from Ground Zero of the outbreak in China.

Tonight, the city of Wuhan, the epicenter of the outbreak, is racing to contain the potential

spread of a deadly new strain of coronavirus. And now a disturbing development. China today says

it has confirmed cases of human-to-human transmission of the mystery illness. In one case,

a hospital patient is said to have infected 14 medical workers. Airline workers are already doing

temperature checks on some flights leaving Wuhan, not allowing passengers to deplane without getting

one. CBS News obtained this video showing health officials in Wuhan in full hazmat gear

at a treatment facility investigating the virus.

The World Health Organization says an animal is probably the source of this new virus,

and this now closed seafood market is probably ground zero.

This is as close as police will let us get.

Dr. Anthony Fauci from the National Institutes of Health says human to human transmission is a game changer.

When you get sustained transmissibility from one person to another to another to another,

then you have a more serious problem because then that

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