Marshfield study finds 51% of deer ticks carried Lyme bacteria

More than half of the adult female deer ticks tested through Marshfield Clinic Research Institute’s Tick Inventory via Citizen Science study were carrying Borrelia burgdorferi, the bacterium that causes Lyme disease. Researchers found the pathogen in 51% of 707 adult female blacklegged ticks submitted from Wisconsin and nearby areas, with higher prevalence in western Wisconsin and in the fall. The findings, released in mid-May in a preprint and amplified by Wisconsin media, were higher than researchers expected, though Marshfield scientist Alexandra Linz said they are not the highest ever reported in the state. (wispolitics.com)

Why it matters: For veterinary professionals, the study is another signal that tick exposure risk in the Upper Midwest remains high, and that conversations with pet parents about year-round tick prevention, tick checks, and Lyme vaccination for appropriate dogs need to stay front and center. CDC notes that dogs can be vaccinated against Lyme disease, unlike most other tickborne diseases, and CAPC’s 2026 forecast points to continued expansion of Lyme and other vector-borne risks in areas including Wisconsin. Wisconsin DHS also says Lyme disease is the most commonly reported tickborne illness in the state. (cdc.gov)

What to watch: Marshfield’s TICS project is now in its third year, so watch for larger datasets, seasonal trend updates, and whether veterinary and public health messaging in Wisconsin shifts further toward sustained fall and year-round prevention. (wrn.com)