Hantavirus in Colorado.
Colorado averages 3–5 confirmed Sin Nombre virus HPS cases annually. Western-slope counties — La Plata, Montezuma, and Mesa — see the bulk of cases. Colorado Department of Public Health and Environment recommends rodent-proof storage and wet-cleanup protocols for backcountry users and ranchers.
Frequently asked
How many hantavirus cases has Colorado reported?
Colorado has reported 2 confirmed hantavirus pulmonary syndrome cases year-to-date in 2026, against a 5-year average of 3.8 per year. Case counts vary year-on-year with rodent population cycles.
What rodent carries hantavirus in Colorado?
Deer mouse (Peromyscus maniculatus). Mountain valleys and the Western Slope agricultural belt; spring-summer peak.
Which strain causes hantavirus in Colorado?
Sin Nombre virus is the dominant hantavirus strain in Colorado. It causes hantavirus pulmonary syndrome (HPS) with case fatality typically 30–40%.
Related
Disclaimer. State case counts reflect what CDC NNDSS publishes. The state health department is the authoritative real-time source.