CDC Baseline
State-level historical context for hantavirus pulmonary syndrome in the United States, drawn from CDC's Reported Cases of Hantavirus Disease page. The cumulative confirmed count is concentrated in western and southwestern states with deer-mouse reservoirs.
Key facts
CDC's Reported Cases of Hantavirus Disease page lists 864 laboratory-confirmed hantavirus pulmonary syndrome cases in the United States through 2023 — the most recent year published in the agency's annual summary. That is the cumulative confirmed count from initial recognition of the syndrome in 1993 through 2023, not an annual rate. Cases reported during 2024 through 2026 continue to flow through NNDSS and will appear in subsequent annual updates.
A small set of western and southwestern states accounts for the bulk of confirmed records.
The deer mouse (Peromyscus maniculatus) is the primary reservoir for Sin Nombre virus, the most common hantavirus causing HPS in the U.S. Its range and density across the rural West, combined with cabins, sheds, and seasonal closed-up structures, produces the exposure profile that drives the historical case map.
These records are laboratory-confirmed. Probable, suspect, and unreported cases are not in this number. The 864 figure should not be read as the total number of people exposed or infected — only as the count of records that met the CDC/CSTE confirmed surveillance case definition.
Historical CDC data describes HPS case-fatality at approximately 36 percent — roughly one in three confirmed cases. That figure is cumulative context across the entire 1993-to-present record; it is not a personal risk estimate, and most people with rodent exposure never develop HPS.
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