Health care workers worldwide are learning in real time about the new coronavirus from China, as an increasing number of cases are being diagnosed and studied around the globe.

As of Friday morning, cases of the coronavirus swelled to well over 800 in China, the epicenter of the outbreak, and stretched into neighboring countries, as well as the United States, where one patient is being treated and a second case was confirmed by the Centers for Disease Control and Prevention Friday morning.

Although this particular virus — which appears to have originated from infected live animals sold at a market in Wuhan, China — is new, coronaviruses are not. Doctors know that these viruses in general can circulate easily among humans.

Stopping its spread

Coronaviruses "primarily spread through close contact with another individual, in particular through coughing and sneezing on somebody else who is within a range of about 3 to 6 feet from that person," said Dr. Kathy Lofy, a state health officer for Washington, where the patient with confirmed coronavirus has been hospitalized.

If an infected person sneezes or coughs onto a surface — a countertop, for example — and another person touches that surface and then rubs his or her eyes or nose, for example, the latter may get sick.

It's still unclear, however, how long the virus particles for this new coronavirus can live on surfaces.

What's more, it's unknown at what point a person with the virus becomes contagious. Health care workers are operating under the assumption that the incubation period for the illness is about 14 days, meaning that it takes roughly that amount of time for symptoms to show up after a person is infected. Scientists still do not know whether a person is infectious during the incubation period.

Infectious disease experts are hoping to glean insight into the new virus from another well-known coronavirus, the SARS virus. That coronavirus caused widespread global disease during its outbreak from 2002 to 2003.

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"While we do not know all of the mechanisms of spread of the epidemic so far, there is likely spread by droplets and contaminated surfaces, and possible airborne [spread], similar to SARS," Dr. Mark Denison, a virologist at the Vanderbilt University Medical Center, said. Denison has been studying coronaviruses for more than three decades.