In the U.S., the number of coronavirus cases has grown to more than 530. On Sunday, the country’s leading expert on infectious diseases, Dr. Anthony Fauci, said regional lockdowns could become necessary and recommended that those at greatest risk — older adults and people with underlying health conditions — abstain from travel.

Here are the latest updates on the virus and a map of where it has spread.

Related: A cruise ship that has been held off California after 21 people aboard tested positive for the virus is set to dock today in Oakland. Passengers and crew members will be quarantined on four military bases around the country, the authorities said. The State Department on Sunday advised Americans against traveling on cruise ships.

Closer look: Dr. Fauci has become the chief explainer of the epidemic, partly because other government scientists have either avoided the spotlight or been reined in by the Trump administration.

News analysis: President Trump, who seems at his strongest politically when he has a human target to attack, has found it harder to confront the threat of an invisible pathogen, our chief White House correspondent writes.