WASHINGTON — A Chicago woman has become the second U.S. patient diagnosed with the dangerous new virus from China, health officials announced Friday.

The woman in her 60s returned from China on Jan. 13 without showing any signs of illness, but three or four days later she called her doctor to report feeling sick.

The patient is doing well and remains hospitalized “primarily for infection control,” said Dr. Allison Arwady, Chicago’s public health commissioner.

Earlier this week, a man in his 30s in Washington state became the first U.S. patient, also diagnosed after returning from a trip to the outbreak’s epicenter in central China.

The Centers for Disease Control and Prevention is expecting more Americans to be diagnosed with the newly discovered virus in coming days, as worldwide the number of confirmed cases has passed 800.

The virus can cause fever, coughing, wheezing and pneumonia. It is a member of the coronavirus family that’s a close cousin to the deadly SARS and MERS viruses that have caused outbreaks in the past.

Still, “CDC believes that the immediate risk to the American public continues to be low at this time, but the situation continues to evolve rapidly,” said CDC’s Dr. Nancy Messonnier.

And those first two patients did the right thing, recognizing their travel risk and alerting doctors to it, so that health authorities could get them isolated to prevent spread, tested promptly, and start monitoring people who’ve had close contact with them.

It took about 36 hours for the first U.S. patient to be tested, receive the results from the CDC in Atlanta and put in the hospital after he went to a clinic Sunday, according to a timeline released Friday by health officials in Washington state.