Four weeks after Wisconsin’s first case of the B117 coronavirus variant was found in Eau Claire County, another case of the variant has turned up — this time on the other side of the state.

A Waukesha County resident has tested positive for the new variant, a strain that’s believed to be more infectious than the original SARS-CoV-2 virus, Wisconsin officials announced Tuesday. The B117 variant is the same strain that overwhelmed Great Britain’s health system in November and December.

The Eau Claire County resident who tested positive for the B117 variant in late December had travelled internationally before testing positive.

State officials on Tuesday said they didn’t yet know if the Waukesha County resident had traveled overseas, or if they expected any community spread from that case.

“I think the likelihood (of community spread) is high,” said Dr. Ryan Westergaard, the state health department’s Bureau of Communicable Diseases’ chief medical officer. “Not necessarily from this particular case, but through the amount of interstate and international travel that’s still happening.”

The state is looking for cases of the B117 strain through a process called whole genome sequencing, which is currently only conducted on less than 1% of COVID-19 tests in Wisconsin, Westergaard said at a Tuesday press conference.

Because four labs in the state can only test a small fraction of samples right now, “we’re detecting the tip of the iceberg, and it’s likely other cases exist,” Westergaard said.

As of Sunday, there were 690 cases of the B117 variant in the United States. Two are in Wisconsin. Thirty-three states have reported cases, according to the Centers for Disease Control and Prevention.

The new strain B117 has many mutations — nearly two dozen — and eight are on the spike protein that the virus uses to attach to and infect cells, the Associated Press reported. The spike is what vaccines and antibody drugs target.

Though new variants are emerging, Wisconsin appears to be fighting back the virus to some degree. The state’s seven-day average of new cases was 970 per week, the lowest it’s been since September. (At the state’s peak in November, it averaged 6,500 cases per week.)

But Westergaard cautioned that it’s no time to stop wearing masks or social distancing, even as vaccines ramp up.

“The unanswered question is how widespread community transmission of variants is,” Westergaard said Tuesday. “It’s not a given they’re going to become the predominant strains, but many people who have observed the spread of these in other settings have said the possibility is reasonably good.”

Eau Claire County added just six new cases of COVID-19 on Tuesday. Another three county residents have died of the virus since Monday.

In total, nearly 10,800 Eau Claire County residents have contracted the virus, and 104 have died.

Contact: 715-833-9206, sarah.seifert@ecpc.com, @sarahaseifert on Twitter

Sarah Seifert is the L-T's education and health reporter. She has worked as a journalist in the Chippewa Valley since 2017 and joined the L-T in 2019. Get in touch at sarah.seifert@ecpc.com or on Twitter @sarahaseifert.