RIVERSIDE (CBSLA) – More than 50 people in Riverside County are under directives to self-quarantine due to having possibly been exposed to the coronavirus.

A Riverside County Public Health Department spokesperson confirmed to CBS2 Friday that 54 people are currently under self-quarantine orders.

The situation began in mid-January when the U.S. Centers for Disease Control notified the state that some Riverside County residents may have been exposed to the virus. The state in turn notified Riverside County, which contacted the affected people and directed them to self-quarantine.

Since that time, some people have not shown symptoms and were able to resume normal life when their quarantine ended. New people have been added to the list on a daily basis.

The standard quarantine period for coronavirus is 14 days.

On Tuesday, officials confirmed that a Riverside County resident tested positive for the coronavirus after being evacuated from the Diamond Princess cruise ship off the coast of Japan. The unidentified patient was being treated in Northern California and is expected to recover.

Hundreds of passengers and staff contracted coronavirus while aboard the Diamond Princess, which has been docked off the Japanese port city of Yokohama for the past several weeks. As of Friday, there were 705 coronavirus cases connected to the Diamond Princess, according to CNN. Based on the latest CDC numbers Friday, 44 U.S. passengers who were aboard the Diamond Princess and have been flown back to the U.S. have tested positive for the virus.

On Jan. 29, nearly 200 American evacuees were flown in to March Air Reserve Base in Riverside County from the Chinese province where the coronavirus is believed to have been started. That quarantine expired Feb. 11 and those people were released. None of them tested positive for coronavirus.

There were 59 confirmed cases of coronavirus in the U.S. as of Thursday. Of those, 33 were in California. Of the 33, 24 were from repatriation flights, according to the California Department of Public Health, meaning they were U.S. citizens who had contracted the disease outside the country and had been flown back for treatment and quarantine. Most of those were people who got the virus aboard the Diamond Princess.

According to the CDC, COVID-19 is spread from person-to-person through close contact, usually within 6 feet, and mainly via respiratory droplets when an infected person coughs or sneezes. Symptoms include fever, cough and shortness of breath. People are likely most contagious when they are most symptomatic.