In late June 2025, a Herkimer County resident fell ill with symptoms consistent with a tick-borne infection. When the test results came back, they showed something that had never been detected in New York before: Borrelia mayonii, a bacterial cause of Lyme disease previously identified only in Minnesota and Wisconsin. The patient had not recently traveled, suggesting the infection was acquired locally.

A report published this week by the Centers for Disease Control and Prevention documents what health officials found next. The patient was treated with doxycycline and made a full recovery, but the investigation that followed uncovered ticks on the property carrying the same bacterium, with signs that local transmission may already be underway.