(The Center Square) – There is a new county and more cases connected to Wisconsin’s measles outbreak.

The Wisconsin Department of Health Services on Tuesday said investigators are looking into “five probable cases” in Rock County.

“The cases are considered probable based on symptoms but have not been confirmed by laboratory testing. These cases are linked to each other but are not connected to the ongoing outbreak in Southwest Wisconsin. The source of the infection remains unknown,” DHS said in a statement.

While the cases in Rock County have not yet been confirmed, DHS on Tuesday said other cases have been.

"As of Oct. 13, 2026, the Wisconsin Department of Health Services has confirmed 267 cases of measles in Wisconsin so far in 2026," DHS added.

There were nine total confirmed cases in the state last year, one in 2024 and none in 2023.

As has been the case since the beginning of this year's outbreak, most of those cases continue to be in southwestern Wisconsin.

"There have been 237 confirmed and six probable cases in the outbreak in Grant, Iowa, Lafayette, and Vernon counties," DHS noted. "The ongoing investigation indicates that measles is spreading locally. DHS, in coordination with Grant, Iowa, Lafayette, and Vernon County Health Departments, are working to identify and notify people who may have been exposed to the measles virus."

It's not yet known what the price tag will be for the measles investigation.

While the Department of Health Services is one of Wisconsin's largest state agencies, with more than $11 billion in state aid in the current budget alone, DHS said it has just $500,000 to share with "local and tribal health departments for communicable disease prevention, surveillance, contact tracing, and outreach."

This year's measles outbreak is the largest in Wisconsin since at least 2019.

In 2021, DHS reported 22 cases of measles, though those cases were all tied to Afghan refugees who were being housed at Fort McCoy.

There were no reported cases in 2020 or 2019.

If this week's cases from Rock County are confirmed, it would become the seventh county in Wisconsin to see at least one measles case this year.