What we know now
As of October 20, 2026, Wisconsin DHS reports five probable measles cases in Rock County that are linked to one another. DHS says the cases are not connected to the southwestern Wisconsin outbreak and the source is unknown.
The cited official sources describe this event as active as of Oct 20, 2026.
Cited update: Wisconsin Department of Health Services
Where it has been reported
The cited record identifies Rock County, Wisconsin.
These locations come from the cited sources and are not a personalized risk map.
See every source-supported area ↑Reported cases and outcomes
As of Oct 20, 2026, the current cited record does not provide a source-supported case total. That is not the same as zero cases.
The record does not provide totals for hospitalizations and deaths; missing values do not mean zero.
Return to the situation facts ↑What the source recommends
Wisconsin DHS advises people with symptoms to stay home and call a health care provider before visiting, and encourages residents to check their MMR vaccination status.
This guidance is attributed to the linked official source; check that source for changes.
See the event-specific guidance ↑How we verified this update
This record links 1 official source.
The primary cited source is Wisconsin Department of Health Services.
Counts and status are presented as of Oct 20, 2026; a later source update may change them.
The CDC link provides general condition background and does not verify this specific event.
Review this alert’s sources ↑Frequently asked questions
What is the current status of this event?
The cited official sources describe this event as active as of Oct 20, 2026.
Where has this event been reported?
The cited record identifies Rock County, Wisconsin. These locations come from the cited sources and are not a personalized risk map.
How many cases have been reported?
As of Oct 20, 2026, the current cited record does not provide a source-supported case total. That is not the same as zero cases. The record does not provide totals for hospitalizations and deaths; missing values do not mean zero.
What is known about the cause or exposure?
The record identifies the pathogen as Measles.
What actions does the official source recommend?
Wisconsin DHS advises people with symptoms to stay home and call a health care provider before visiting, and encourages residents to check their MMR vaccination status. This guidance is attributed to the linked official source; check that source for changes.
How was this update verified?
This record links 1 official source. The primary cited source is Wisconsin Department of Health Services. Counts and status are presented as of Oct 20, 2026; a later source update may change them. The CDC link provides general condition background and does not verify this specific event.