Species
Sin Nombre virus (SNV)
The "nameless" virus — the New World hantavirus identified during the 1993 Four Corners outbreak and the leading cause of hantavirus pulmonary syndrome (HPS) in the United States and Canada.
Quick facts
- Family / genus
- Hantaviridae / Orthohantavirus
- Reservoir
- Deer mouse (Peromyscus maniculatus; western lineages now reclassified as P. sonoriensis)
- Range
- Western US, southwestern Canada
- Disease
- Hantavirus pulmonary syndrome (HPS / HCPS)
- ICD-10
- A98.5 — Hantavirus (cardio)-pulmonary syndrome
- Case-fatality
- ~30–50%; CDC US cohort 1993–2023 ~35%
- Vaccine
- None licensed
Symptoms
- Prodromal phase (1–5 days): fever, severe muscle pain (especially thighs and back), headache, GI symptoms (nausea, vomiting, abdominal pain). Often mistaken for flu. Sore throat and runny nose are typically absent.
- Cardiopulmonary phase: rapid onset of shortness of breath; chest X-ray shows bilateral pulmonary edema (ARDS pattern); blood pressure crashes within 24–48 hours of pulmonary symptoms.
- HPS lab triad: thrombocytopenia, >10% circulating immunoblasts, hemoconcentration (rising hematocrit).
Transmission
Inhalation of dust contaminated with deer-mouse urine, feces or saliva. No person-to-person transmission has been documented for Sin Nombre virus. Most US cases trace to home or occupational rodent exposure. Read more on transmission →
Where the cases are
CDC cumulative data (1993–2023): 890 US HPS cases, 309 deaths. Top death-count states: New Mexico (54), Colorado (45), Arizona (32), California (24), Washington (20). Median patient age 38; 62% male.
Treatment
No specific antiviral. Care is supportive ICU — careful fluid management, vasopressors, mechanical ventilation. Early ECMO raises survival to ~80% in CDC reports when started at the first sign of decompensation. Ribavirin trials in HPS have not shown benefit. See Syndromes — treatment.
History & name
First identified in the 1993 Four Corners outbreak. The name Sin Nombre ("nameless" in Spanish) was chosen after several proposed place-names — including "Muerto Canyon virus" — were rejected by local Navajo communities. The reservoir is the deer mouse, sometimes split taxonomically into P. sonoriensis in the western US.
FAQ
What does Sin Nombre virus do?
Causes HPS — flu-like prodrome followed by sudden severe pulmonary edema and shock.
Where in the US is Sin Nombre virus?
Across the deer-mouse range, primarily west of the Mississippi. New Mexico, Colorado, Arizona, California and Washington lead in case counts.
What's the ICD-10 code?
A98.5, "Hantavirus (cardio)-pulmonary syndrome."
Is there a Sin Nombre virus vaccine?
No. Asian hantavirus vaccines target Hantaan and Seoul; they are not expected to protect against Sin Nombre.