reservoir, geography and case-fatality compared
Andes virus vs Sin Nombre virus
| Feature | Andes virus (ANDV) | Sin Nombre virus (SNV) |
|---|---|---|
| Syndrome | HPS (Hantavirus Pulmonary Syndrome) | HPS |
| Geography | Patagonia and northeast Argentina; Lake District + southern Chile; foci in Uruguay, Bolivia, southern Brazil | Western US (Four Corners and beyond), western Canada, parts of Mexico |
| Reservoir | Long-tailed pygmy rice rat (Oligoryzomys longicaudatus) | Deer mouse (Peromyscus maniculatus) |
| Person-to-person transmission | Documented (household, sexual, healthcare, shipboard) | Not documented |
| Case-fatality ratio | ≈ 30–40% | ≈ 35–40% |
| Seasonality | Austral summer (Nov–Apr) | Spring–summer; year-round sporadic |
| First described | 1995, Argentina | 1993, Four Corners (USA) |
| Vaccine available | No (mRNA candidates in trials) | No |
Andes virus (ANDV) and Sin Nombre virus (SNV) are the two flagship hantaviruses of the Americas. Both cause hantavirus pulmonary syndrome (HPS) — a brief flu-like prodrome followed by precipitous lung capillary leak and respiratory failure. Both kill roughly one in three patients even with intensive care. Their differences matter operationally.
Geography and reservoir. ANDV follows its host — the long-tailed pygmy rice rat (Oligoryzomys longicaudatus) — through southern South America, with Patagonia and the northeastern Argentine provinces as the highest-incidence regions, and the Chilean Lake District as a steady annual focus. SNV is a temperate North American virus carried by the deer mouse (Peromyscus maniculatus), with cases concentrated in the southwestern US plateau and dispersed across the western states and Canada.
Person-to-person transmission. This is the single most important clinical and public-health distinction. ANDV is the only hantavirus with documented human-to-human transmission, observed across household, sexual, healthcare and most recently shipboard contexts. SNV, despite extensive surveillance, has never been shown to spread between people. Suspected ANDV cases warrant droplet and contact precautions; suspected SNV cases require only standard precautions.
Operational implications. A returning traveller from Patagonia presenting with prodromal HPS-compatible illness is a contact-tracing event. A returning traveller from the Four Corners is not. ANDV outbreaks tend to cluster in family or healthcare networks; SNV outbreaks are point-source rodent-exposure events (a cabin, a shed, a barn).
Use the live map to see active ANDV and SNV events with sources, dates, and confidence ratings.