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59 people have been diagnosed with novel coronavirus in the U.S., an increase in cases largely driven by the repatriation of American citizens from the cruise ship Diamond Princess in Japan, the Centers for Disease Control and Prevention said Wednesday.

The big picture: As more countries experience community-wide transmission, CDC official Dr. Nancy Messonnier told reporters Tuesday that it's now a question of when the same will happen in the U.S. — and how many citizens will develop a severe illness.

  • Two of the cases were contracted through person-to-person contact.

What's happening: The CDC outlined standard public health measures to mitigate spread of the virus on Tuesday, including what closing schools and businesses would look like in a U.S. pandemic.

  • "We really want to prepare the American public for the possibility that their lives will be disrupted," Messonnier said.
  • Schools and workplaces may need to explore tele-commuting and online assignments. Hospitals also may need to regroup patients.

Full coverage: The latest coronavirus developments

Editor's note: This story has been updated to a more current case count in the U.S.

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Where the CDC went wrong with its coronavirus response

Photo: Tami Chappell/AFP/Getty Images

The Centers for Disease Control and Prevention mishandled the coronavirus pandemic, sowing mistrust among health experts and the public, according to a sweeping report by the New York Times.

Why it matters: It's been reported that a faster and more organized response from the federal government could have saved thousands of lives.

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U.S. coronavirus updates

Data: The Center for Systems Science and Engineering at Johns Hopkins; Map: Andrew Witherspoon/Axios. This graphic includes "probable deaths" that New York City began reporting on April 14.

The U.S. reported for the first time on Wednesday over 50,000 novel coronavirus cases in 24 hours, but the total could be as high as 400,000 to 500,000 undiagnosed cases per day, former FDA chief Scott Gottlieb said.

The big picture: Health experts including NIAD director Anthony Fauci and those from the CDC say coronavirus cases have been undercounted in the U.S. considering the virus has a wide-ranging effect on various populations.

Jun 4, 2020 - Health

HHS requests data on race and ethnicity with coronavirus test results

A nurse writes a note as a team of doctors and nurses performs a procedure on a coronavirus patient in the Regional Medical Center on May 21 in San Jose, California. Photo: Justin Sullivan/Getty Images

The Department of Health and Human Services moved on Thursday to require that an individual's race, ethnicity, age and sex be submitted to the agency with novel coronavirus test results.

Why it matters: Some cities and states have reported the virus is killing black people at disproportionately high rates. There are gaps in the national picture of how many people of color are affected, since the data has not been a requirement for states to collect or disclose.