What is Andes virus?
Andes virus (ANDV) is a species of hantavirus first identified in Argentine Patagonia in the mid-1990s. Its primary natural reservoir is the long-tailed pygmy rice rat (Oligoryzomys longicaudatus), a small rodent native to southern Argentina and Chile.
Origin and discovery
ANDV was first isolated in 1995 following a cluster of hantavirus pulmonary syndrome cases in El Bolsón, Argentina. Sequencing showed it was distinct from Sin Nombre virus (the North American HPS strain) and revealed an unusual epidemiological pattern: clusters among household and healthcare contacts that could not be explained by shared rodent exposure.
Genetic lineage
Andes virus belongs to the genus Orthohantavirus in the family Hantaviridae. Its genome is a tri-segmented, negative-sense, single-stranded RNA. Multiple closely related lineages circulate across South America (e.g. Andes Sout, Andes Cent BsAs, Andes Lechiguanas) and share the same reservoir species or close relatives.
Geographic spread
- Argentine Patagonia (Río Negro, Chubut, Neuquén, Santa Cruz)
- Southern and central Chile (Aysén, Los Lagos, Los Ríos, Araucanía, Biobío)
- Sporadic reports in northern Argentina and bordering regions
How Andes differs from other hantaviruses
- Person-to-person transmission — confirmed only with Andes virus.
- Higher rate of household clusters than Sin Nombre virus.
- Comparable case fatality to other HPS strains (~30–40%).
Why person-to-person spread matters
Most hantaviruses cannot move directly between people — exposure to infected rodent excreta is required. Andes virus is the exception. Documented transmission events involve close, prolonged contact: spouses, parents and children, and healthcare workers caring for critically ill patients. This is why Andes outbreaks (such as the MV Hondius situation in 2026) are managed with strict isolation and contact tracing.
Sources
- CDC — Andes virus and hantavirus pulmonary syndrome
- PAHO — Hantavirus situation in the Americas
- Ministerio de Salud, Argentina — Hantavirus epidemiological bulletins