Hantavirus in United States — 2025
United States hantavirus surveillance — continuing Mono County activity and routine state reporting
Overview
US Sin Nombre virus surveillance through 2025 continued to be dominated by the western and southwestern states — New Mexico, Colorado, Arizona, California, Washington, and Montana — with cumulative case counts of roughly 25–60 per year nationwide, consistent with the multi-decade CDC baseline. Mono County, California remained a watchpoint following the 2024 cluster; state and county health agencies maintained targeted advisories around deer-mouse exposure in the Eastern Sierra. Seoul virus pet-rat surveillance continued at low levels, with periodic case identification through voluntary colony testing.
United States baseline
Highest case counts in western and southwestern states (NM, CO, AZ, CA). Sin Nombre virus is the dominant strain.
Source: CDC Hantavirus Surveillance
Relevant strains
References & primary sources
Other years tracked for United States
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Read more: Live United States tracker · Hantavirus strains · Historical outbreaks · Prevention