Wisconsin has recorded 163 measles cases so far in 2026, and 161 of them- 155 confirmed and six probable- belong to the southwestern outbreak spanning Grant, Iowa, and Lafayette counties, according to the Wisconsin Department of Health Services. Four cases were added in the three days before the state's latest update.
The state also now lists measles virus detections in wastewater from all three outbreak counties. The most recent came from Iowa County samples collected August 26 and August 31. Grant County had a detection on August 19 and Lafayette County on August 25. No other Wisconsin site has recorded a recent detection.