An informed guide to the global outbreak, with the latest developments and expert advice about prevention and treatment.

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• Italy closes its schools
• One case becomes 10 in the N.Y. suburbs
• A W.H.O. expert discusses China’s fight
• Get the latest updates here , plusmaps andfull coverage

Italy closes all its schools

The country ordered all schools — from day care centers to universities — to shut down until at least March 15 as the outbreak there grew rapidly. Italian students will join hundreds of millions of children who’ve been forced to stay home because of the coronavirus in China, South Korea, Iran, Japan, France, Pakistan, the United States and elsewhere.

The closings are an extraordinary public health experiment, with many ripple effects. The burden is likely to fall particularly hard on women, who across the world still perform most child care duties.

Gao Mengxian, a security guard in Hong Kong, has stopped going to work so she can watch her daughters. Masks are pricey, so she ventures outside just once a week. She spends most of her time helping her daughters, 10 and 8, with their online classes, fumbling through technology that leaves her confused and her daughters frustrated.

“They’re always saying: ‘When can we go out to play? When can we go to school?’” Ms. Gao said.

A case swiftly becomes a cluster in New York

One coronavirus case, a man of around 50, has quickly led health officials to discover at least nine more infected people around the New York City suburb of New Rochelle. They include the man’s wife and two children; a friend who drove him to the hospital; a friend who was in “close proximity” with the man; the friend’s wife, and three of their children.

Roughly 1,000 people in the area have been told to self-quarantine, including some nurses and doctors at a nearby hospital and people who attended a funeral and a bat mitzvah at a local synagogue.

The man’s daughter’s high school and his son’s college, Yeshiva University, canceled classes; so did New York Law School after a student there reported having contact with the man, who works at a law firm in Manhattan.

Only the man at the center of this cluster of cases has been hospitalized; he was in stable condition and improving on Wednesday. It is unclear how he initially contracted the virus.

Takeaways from the front lines in China

A World Health Organization team led by Dr. Bruce Aylward just spent two weeks in China monitoring the fight against coronavirus. Donald G. McNeil Jr., our infectious-disease reporter, got the download :

Are cases in China really going down?

I know there’s suspicion, but at every testing clinic we went to, people would say, “It’s not like it was three weeks ago.” It peaked at 46,000 people asking for tests a day; when we left, it was 13,000. Hospitals had empty beds. I didn’t see anything that suggested manipulation of numbers.

Is everyone catching it from everyone?

No. Seventy-five to 80 percent of all clusters are in families. You get the odd ones in hospitals or restaurants or prisons, but the vast majority are in families.

If you’re in China and think you might have coronavirus, what do they do?

You would be sent to a fever clinic. They would take your temperature, your symptoms, medical history, ask where you’d traveled, your contact with anyone infected. They’d whip you through a CT scan. … Each machine did maybe 200 a day. A typical hospital in the West does one or two an hour.

Who pays for testing and treatment?

The government made it clear: Testing is free. And if it was Covid-19, when your insurance ended, the state picked up everything.

In the United States, that’s a barrier to speed. People think: “If I see my doctor, it’s going to cost me $100. If I end up in the I.C.U., what’s it going to cost me?” That’ll kill you.

Hot spots

• Italy: Infections surged to more 3,000, while deaths shot up to 107, from 79 yesterday. The country has the most reported cases outside China and South Korea.
• France: The second-hardest-hit European country has recorded nearly 300 cases. The French health minister has advised against greeting with cheek kisses, and the Louvre reopened, but with new rules for dealing with visitors.
• Washington State: A 10th patient diedtoday; all but one of the United States’ recorded deaths have taken place in the state. Amazon alerted its staff that one employee in Seattle had tested positive.
• Los Angeles: Los Angeles County declared a state of emergencyafter six new cases were announced today, bringing California’s total to 51. A health screener for the Centers for Disease Control and Prevention who was working at Los Angeles International Airport tested positive for the virus.
• India: New Delhi reported its first coronavirus patient, and the number of cases countrywide jumped to 28 — more than half of them Italian tourists. Prime Minister Narendra Modi has urged Indians to cancel events for Holi, a Hindu festival that begins next week.

What you can do

Six Americans who contracted the coronavirus talked about how they’ve copedwith the loneliness of quarantines and anxiety over the disease. Here are three tips they shared:

• Lean on support networks. Two men who met aboard the Diamond Princess cruise ship have formed a “brotherhood of the virus,” keeping each other’s spirits up over WhatsApp.
• Use video-call apps like FaceTime to stay connected with friends, family and pets.
• Turn to stress-reducing activities that can be done alone indoors, such as exercise, meditation or prayer.

What should you know if you’re pregnant ? First, try not to panic: One study found that infants born to women with the disease appeared to be healthy and virus-free at birth.

Going on a cruise? You might be able to cancel, but a doctor’s note could be necessary. If you go, there are stricter hygiene measures onboard. Here are other things to know.

Don’t forget the basics: The most important things you can do are to wash your handsfrequently — scrubbing for at least 20 seconds — and avoid touching your face.

What else we’re following

• As more concerts and shows around the world are canceled, performers and organizations have found creative ways of bringing the arts to the people.
• The end of fashion month rolled out in Paris, with “a barely restrained desire to flee” replacing the usual fanfare, our chief fashion critic reports.
• Watch health care workers in Iran shimmy and shake in full protective gear as they cope with stress on the front lines.
• In The New Yorker, Frank M. Snowden, a professor emeritus of history and the history of medicine at Yale, talks about how pandemics can change history.
• The 2011 thriller “Contagion” is trending on Amazon Prime Video, for obvious reasons. “It felt like I was watching a documentary that has all these movie stars playing real people,” said Barry Jenkins, the director of “Moonlight.”

What you’re doing to prepare

Let us know how you’re preparing. Send us a response here, and we may feature it in an upcoming newsletter.