San Bernardino County over the weekend reported a case of the coronavirus variant first detected in Brazil, prompting calls for residents to remain steadfast about wearing masks and following social distancing guidelines as more businesses reopen.

It’s the first variant of this kind confirmed in California, adding to a host of other types of coronavirus mutations detected in the state, including homegrown variants and one first found in the United Kingdom.

The infection was detected in a man in his 40s whose positive test sample was collected on March 2 and later confirmed to be the variant through sequencing, county officials said in a news release.

The man, who has not been vaccinated, reported experiencing symptoms and told contact tracers he was self-isolating at home. It remains unclear how he was exposed to the variant.

“We are taking immediate and aggressive action to contact trace and contain the virus and working with the CDPH in expanding whole genomic sequencing to identify more cases,” San Bernardino County Health Officer Dr. Michael Sequeira said in a statement.

The variant is believed to be more contagious than the most common coronavirus strain, and has sparked alarm since it was detected in January.

Though it’s not yet clear whether the variant is more resistant to current vaccines, officials say the Johnson & Johnson vaccine, which was tested in Brazil, showed 0% mortality and 85% success in preventing hospitalizations and severe infections.

“If we can contain this and continue vaccinating, we will continue to move forward,” Sequeira said. “If we complete the vaccination effort, at maximum pace and urgency, we will contain and virtually eliminate this and other variants.”

The discovery comes as San Bernardino County’s restaurants, gyms, movie theaters and other businesses started reopening indoors Sunday following the region’s move to the red tier, the second-most restrictive stage in the state’s four-tier reopening plan.

Scientists use genomic sequencing to decode the genes and find new variants. But because this is being done to a very small number of California’s coronavirus samples, officials say the variants are likely much more widespread than what is confirmed.

So far, the California Department of Public Health reports 265 cases of the variant first seen in the United Kingdom, and three of the variant that emerged in South Africa. Those two have been designated “variants of concern” by the Centers for Disease Control and Prevention because their mutations are believed to make them more contagious.

Another two variants have been found in greater numbers in California. They’re being dubbed the “West Coast Strain” by the state.