Andes Virus Infographic

Summary

The Andes virus (ANDV) is a highly lethal orthohantavirus belonging to the family Hantaviridae, first identified in 1995 in Chile and Argentina, where it remains endemic across Patagonian and Andean ecosystems. It is primarily harbored by the long-tailed pygmy rice rat (Oligoryzomys longicaudatus), which sheds the virus asymptomatically through urine, feces, and saliva. Humans typically become infected by inhaling aerosolized rodent excreta, though ANDV holds the unique and alarming distinction of being the only hantavirus capable of person-to-person transmission — a property demonstrated during multiple outbreaks, including a 2018–2019 cluster in Chubut, Argentina, where the reproduction number reached 2.12 before isolation measures were applied. Upon infection, ANDV targets pulmonary microvascular endothelial cells via β3-integrin receptors, triggering a non-cytopathic but devastating cascade of vascular hyperpermeability, cytokine storm, and pulmonary edema that defines Hantavirus Cardiopulmonary Syndrome (HCPS) — a disease carrying a case fatality rate of approximately 40%. There is currently no approved antiviral treatment or licensed vaccine; management relies entirely on intensive supportive care, with extracorporeal membrane oxygenation (ECMO) representing the most effective rescue intervention in severe cases. Given its pandemic potential, ANDV is classified as a WHO priority pathogen and remains an active subject of vaccine and therapeutic research.

Andes Virus (ANDV)

The Deadly Human-to-Human Hantavirus

Classification

Rank	Name
Kingdom	Orthonavirae
Phylum	Negarnaviricota
Order	Bunyavirales
Family	Hantaviridae
Genus	Orthohantavirus
Species	Orthohantavirus andesense (ANDV)
Disease	Hantavirus Cardiopulmonary Syndrome (HCPS)
WHO Status	Priority pathogen – Pandemic Potential

Reservoir

Oligoryzomys longicaudatus Long-tailed Pygmy Rice Rat – primary reservoir across Chile and Argentina. Asymptomatically sheds ANDV continuously.

Habitat

Forest edges, scrubland, rural dwellings

Shedding

Urine (primary), feces, saliva – aerosol-stable in cool/humid air

Seropositivity

Varies by ecoregion; highest in Patagonia

El Niño Link

Vegetation surges → rodent booms → increased human spillover

Andes Virus Structure

Components

Lipid Envelope: Host Golgi-derived bilayer. Spherical/pleomorphic, 80–120 nm diameter.

Gn Glycoprotein: Binds β3 integrins on endothelial cells. Forms surface tetramers that mediate attachment.

Gc Glycoprotein: Class II fusion protein. Low pH conformational change mediates membrane fusion.

Nucleoprotein (N): 428 aa homotrimer. Encapsidates RNA segments; endonuclease for cap-snatching.

RNA-dependent RNA Polymerase (RdRp): Transcribes mRNA and replicates the genome.

RNA Genome (S/M/L): S: N + NSs; M: Gn/Gc precursor; L: RdRp polymerase.

Viral Life Cycle

1. Attachment - via β3 Integrin
2. Endocytosis - into Early Endosome via clathrin coated pits
3. Membrane Fusion - contents empty into the cytoplasm
4. Transcription - produces mRNA coding for viral proteins
5. Translation - at the ER
6. Replication - via cRNA → −vRNA
7. Assembly - at the Golgi apparatus
8. Release

Andes Virus Transmission Pathways

Reservoir (Source): Rodent Excreta

1. Aerosol (Primary) — High Particle Count
   Aerosol Particle Concentration
   Prevention Action: N95 Respirators & Ventilation
2. Person-to-Person — Cases in a Cluster
   Average cluster size: 3–5
   Prevention Action: Isolation & Contact Tracing
3. Direct Contact — Fomite Persistence
   Time on surface: 2 hours
   Prevention Action: Hand Hygiene & Surface Disinfection

Disease Pathology

Immune Evasion: NSs blocks IFN signaling; N-protein hides caps.

Endothelial Injury: ANDV breaks junctions; vEGF causes leaking.

Cytokine Storm: CD8+/Macrophage activation; massive cytokine surge.

Pulmonary Edema: Plasma in alveoli; bilateral infiltrates.

Outcome: Case Fatality Rate ~40%; Shock & Multi-organ failure; complete recovery possible.

Diagnosis

Method	Window
RT-PCR	Active infection, Days 1–7
IgM ELISA	Days 5–10+
IgG ELISA	Convalescent
IHC	Post-mortem
PRNT	Reference Standard

Current Treatment

Supportive Care (Mainstay)

• ICU/Hemodynamic Monitoring
• Respiratory Ventilation
• Fluid Management
• Vasopressors
• Isolation & PPE

ECMO (Extracorporeal Membrane Oxygenation) Intervention

• Rescue -bypasses lungs to oxygenate blood externally
• V-A ECMO – addresses both cardiac and pulmonary failure simultaneously
• Reduced Mortality in specialist ECMO centers
• Early Transfer to ECMO-capable centers recommended for severe HCPS

Investigational (No Approved Vaccine or Antiviral)

• Ribavirin: In vitro activity but limited clinical benefit for ANDV; not standard of care
• Anti-Gn/Gc Monoclonal Antibodies (MAbs): neutralizing Mabs show promise in animal models; human trials ongoing
• mRNA / VLP Vaccines: in development
• Favipiravir / Molnupiravir: Broad-spectrum antiviral with in vitro activity, but no clinical trial data yet