Public health officials remain on high alert for additional cases of the new strain of coronavirus after two positive diagnoses in Southern California over the weekend.

A total of 110 people in 26 U.S. states are under investigation for possible infection with the deadly strain, a number that is expected to rise, the Centers for Disease Control and Prevention announced.

Five people in the United States have tested positive — the two in California, plus one each in Washington, Illinois and Arizona. No new U.S. cases were confirmed overnight, CDC officials said in a briefing on Monday.

The strain of coronavirus has sickened more than 2,800 people in 16 countries and territories and resulted in more than 80 deaths since it was discovered late last month in central China. The majority of the cases have been reported in the Hubei province, where most of the early victims said they had visited a large seafood and live animal market in the capital city of Wuhan. Symptoms of the virus include fever, coughing and shortness of breath.


Most of the people being tested for coronavirus in the U.S. had either recently traveled to Wuhan or had contact with someone who did, said Dr. Nancy Messonnier, director of the CDC’s National Center for Immunization and Respiratory Diseases.

“At this time in the U.S., this virus is not spreading in the community,” she said, and for that reason, officials continue to believe the immediate health risk to the general U.S. public remains low.

Of the two Southern California cases, one was announced by Orange County health officials late Friday, and the second by Los Angeles County officials on Saturday. The Orange County patient was described only as a traveler from Wuhan. The L.A. County patient is a Wuhan resident who was flying through Los Angeles International Airport on Wednesday on his way back to China, L.A. County public health officials said.

Once at LAX, the patient presented themselves as being symptomatic in conjunction with the CDC traveler screening protocol that was in place, Dr. Muntu Davis, L.A. County health officer, said Monday. The patient is not believed to have left the airport in L.A., outside of being transported to a hospital for treatment.


Davis declined to disclose how many people have been screened for the new strain of coronavirus in L.A. County.

“We are actively involved in CDC screening at LAX, and that number is very dynamic,” he said.

The CDC briefing on Monday came after a top Chinese health official said that the Wuhan coronavirus is contagious during its incubation period, before patients who are infected show symptoms. That would mean it could spread more easily than the severe acute respiratory syndrome (SARS) virus that ravaged Asia in 2003.

Ma Xiaowei, director of the National Health Commission of China, said Sunday that “walking infections” of people who aren’t seriously ill make stopping the spread of the virus more difficult, according to the health commission’s website. Patients often do not have a high fever at first, and there are many mild cases of the illness, he added.


Messonnier said that U.S. health officials are aware of those reports, but that the CDC has no clear evidence of patients being infectious before symptom onset. Still, officials are being “very aggressive and very cautious” in tracking the contacts of infected patients as a result, she said. So far, the CDC has not seen any cases of human-to-human transmission in the U.S., she said.

Meanwhile, a flight carrying government employees who are being evacuated from the U.S. Consulate in Wuhan due to the outbreak is now scheduled to land in Ontario, Calif., rather than at San Francisco International Airport as initially announced.

The charter flight procured by the U.S. State Department is scheduled to depart from Wuhan Tianhe International Airport and head to Ontario on Wednesday morning, China time, a department representative said Monday. All travelers will be screened for symptoms at the airport before the flight departs, the department said.

“Ontario International is an official repatriation center for the West Coast and has conducted extensive training in managing situations such as this,” the Ontario International Airport said in a statement. No disruption to airport operations is expected, the statement said.


California has activated the Medical and Health Coordination Center at the state Department of Public Health in Sacramento, and the center is coordinating with all health agencies and emergency services across the state, the airport said.

“The safety and security of our facilities are of utmost importance to ONT, and we are taking whatever steps are necessary to minimize the risk to our customers, our staff and the community at large,” the airport said.

The coronavirus diagnoses coincide with the height of the U.S. flu season, when hospitals are already seeing an uptick in patients with upper respiratory complaints. As such, it’s difficult to tell whether facilities are seeing more people reporting such symptoms than usual, experts said.

In order to reduce the risk of transmission, public health officials say that people should take the same precautions they’d take to avoid passing along any other virus. Those include frequent handwashing, refraining from touching one’s eyes, nose and mouth with dirty hands, disinfecting frequently touched surfaces and staying away from others when feeling sick.


“In general, it really is your typical flu season recommendations at this point,” Davis said. “That information may change as we learn more about this novel virus, and that’s what world and local health officials are actively trying to understand or confirm.”

Times staff writer Cindy Chang contributed to this report.