Several new cases of the deadly coronavirus have been confirmed in the U.S., bringing the total infections to five as the situation in China, where the bug originated, grows increasingly dire.

Health officials revealed Sunday morning that the U.S. Centers for Disease Control and Prevention confirmed that a person in Orange, County California, who had traveled from Wuhan, China, has the virus. They are listed in “good condition.”

Within hours, authorities revealed two more cases: a student at Arizona State University who is “not severely ill” and a patient who reported he was not feeling well when he got off a plane at Los Angeles International Airport.

“Everything worked as it should,” Dr. Sharon Balter of the L.A. County Department of Public Health. “The patient presented for care, the patient was immediately transported to a hospital, the patient has remained in the hospital.”

Two previous U.S.-based cases—a woman in her 60s from Chicago and a man in his 30s from Washington state—have also been confirmed, but the CDC says the risk to Americans is low.

“There is no evidence that person-to-person transmission has occurred in Orange County,” the CDC said in a statement Sunday. “The current risk of local transmission remains low.”

All of the U.S. patients had traveled from Wuhan, the epicenter of the health crisis. That’s important to note because it means there have been no confirmed person-to-person transmissions inside the U.S.

In each case, health officials will now need to trace the patient’s steps and identify anyone who had close contact with them so they can be monitored—and then isolated, as well, if they develop symptoms.

The new virus—which originated in a market that traded live wild animals and likely passed in snake-to-human contact—has infected more than 2,000 people globally, according to Reuters.

Health officials in Canada were tracking down passengers who flew with a man from Wuhan to Toronto via Guangzhou on a China Southern Airlines flight last Thursday after confirming his diagnosis—the first in Canada.

China is struggling to contain its outbreak and warned Sunday that doctors there have determined the virus can be passed before the carrier shows symptoms. Ma Ziaowei, head of China’s National Health Commission, announced Sunday that the new virus’ incubation period is 10 to 14 days, and it is contagious during that time.

That finding has not been publicly confirmed by U.S. or global health officials. If true, it would present a major complication for containment. For instance, in the U.S., those who had close contact with confirmed patients are not quarantined unless they have symptoms, under the belief that they are not contagious until then.

Chinese authorities have locked down Wuhan and several other cities to stop the virus from galloping across the country, but the U.S. and other countries been given special dispensation to evacuate their citizens. A charter flight from Wuhan to San Francisco with diplomats and private citizens is scheduled for Tuesday, according to CNN. France and Russia have also made similar arrangements.

Two new hospitals being built near Wuhan specifically to house those infected with the virus are expected to be completed in the coming week. The Chinese government has also dispatched hundreds of medical officials and military troops to help manage the crisis in the hardest hit areas of the country.

As The Daily Beast reported, doctors and nurses are so overwhelmed by the explosion of patients, they are wearing diapers so they don’t have to take bathroom breaks. With supplies running low, they are fashioning anti-infection goggles out of spare materials.

In a sign of the virus’ strength, the the death toll in China has climbed from 41 to 56 in just 24 hours. But no deaths have been yet reported in any of the 40 other countries where the virus has been confirmed.

Still, Chinese communities across the world have taken precautions ahead of the Lunar New Year celebrations this weekend, including the cancellation of the annual parade in Paris on Sunday.

Paris mayor Anne Hidalgo said Sunday that she had no choice but to cancel the celebrations. “I have met with the Chinese community in Paris. They are very emotional and concerned, and they have decided to cancel the parade that was scheduled for this afternoon at Place de la Republique,” Hidalgo said Sunday. “They are really not in a mood to party now.”