Hantavirus in United States — 2024

Mono County, California cluster renews HPS attention in the Eastern Sierra

Overview

Through 2024, California's Eastern Sierra recorded a multi-case Sin Nombre virus cluster centered on Mono County. The cluster prompted California Department of Public Health (CDPH) advisories to residents and visitors of the Eastern Sierra about deer-mouse exposure, particularly in vacation cabins, sheds, and seasonally occupied structures opened after winter. The 2024 events reinforced that HPS risk in the United States remains concentrated in the western and southwestern states where deer-mouse populations are densest. Statewide reporting and continuing surveillance into 2025 placed renewed emphasis on rodent-exclusion measures in rural and recreational properties.

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 strain

References & primary sources

• California Department of Public Health — Hantavirus
• CDC — Hantavirus Surveillance

Other years tracked for United States