• California has identified the state's first case of the new and more infectious strain of Covid-19 that was initially discovered in the United Kingdom, Gov. Gavin Newsom said.
• During a Q&A with White House coronavirus advisor Dr. Anthony Fauci, Newsom said the case was detected in the southern part of the state.
• Fauci, however, said the news didn't come as much of a surprise, adding that he would expect similar reports to eventually arise from other states.

California health officials have identified the state's first case of a new and more infectious strain of Covid-19 that was initially discovered in the United Kingdom.

The patient is a 30-year-old man in San Diego County who began showing symptoms on Sunday, county officials confirmed Wednesday.

"I don't think that the Californians should feel that this is something odd. This is something that's expected," White House coronavirus advisor Dr. Anthony Fauci said Wednesday during a live Q&A session with California Gov. Gavin Newsom. Fauci said other states will likely soon identify their own cases of the new strain.

San Diego County Supervisor Nathan Fletcher said the patient was tested for Covid-19 on Tuesday morning. Because he hadn't traveled, state officials believe there are other cases in the county with the new strain, Fletcher said at a news briefing after Newsom disclosed the case.

Fletcher urged residents to follow the public health orders over the next few days to prevent further stress on the county's hospitals, which are seeing "tremendous strain" from an onslaught of Covid-19 patients.

On Tuesday, Colorado health officials confirmed the nation's first case of the B.1.1.7 coronavirus variant. During a news briefing Wednesday, Colorado Gov. Jared Polis said the state was investigating a potential second case of the new strain.

Officials from the Centers for Disease Control and Prevention said earlier Wednesday that the new strain could add pressure to the nation's hospitals, which are already overwhelmed with Covid-19 patients.

Dr. Henry Walke, the agency's Covid incident manager, said the new variant appears to spread "more easily and quickly than other strains," but it does not seem to make people more sick or increase their risk of death.

One particularly concerning aspect of the case in Colorado was that the patient hadn't been traveling, "suggesting this variant has been transmitted from person to person in the United States," Walke told reporters on a conference call.

Some good news: The new variant doesn't appear to make the vaccines less effective and it also doesn't appear to make it harder to diagnose with existing tests, Fauci told Newsom. The U.K. has also found that people who were already infected with previous strains of Covid-19 don't seem to get reinfected with this new variant.

What researchers still need to determine is whether the new strain might be resistant to treatment with monoclonal antibodies, which have been successful in helping some patients recover from the disease, Fauci said. Unlike vaccines, which triggers an immune response that attacks different parts of the virus, monoclonal antibodies attack a very specific component, the nation's leading infectious disease expert said.

Monoclonal antibodies have shown promising benefits if the virus is caught early enough. President Donald Trump credited Regeneron's treatment for making him feel better "immediately" when he was infected and eventually hospitalized with Covid-19 in early October.

"So that's what we know about it now, but we're following this extremely carefully," Fauci said, adding that they're examining the strain at the National Institutes of Health and a number of laboratories throughout the country.

— CNBC's Will Feuer and Amanda Macias contributed to this report.