Hantavirus

Orthohantaviruses are rodent-borne RNA viruses in the family Hantaviridae that cause two major human diseases with distinct geographic distributions: hemorrhagic fever with renal syndrome (HFRS), which is more common in Europe and Asia, and hantavirus pulmonary syndrome (HPS), primarily reported in the Americas. HFRS is characterized by fever, vascular leakage, and acute kidney injury, whereas HPS presents with severe pulmonary edema and respiratory failure, often with high mortality rates.

Among New World hantaviruses, Andes virus (ANDV), classified as Orthohantavirus andesense, is of particular importance because it is strongly associated with severe HPS in Argentina and Chile and is the only hantavirus with well-documented evidence of person-to-person transmission. The ANDV genome is approximately 12 kb long and consists of three negative-sense single-stranded RNA segments: the small (S) segment encoding the nucleocapsid protein and a nonstructural protein, the medium (M) segment encoding the glycoprotein precursor Gn/Gc, and the large (L) segment encoding the viral RNA-dependent RNA polymerase. These segmented RNAs are enclosed within ribonucleoprotein complexes and surrounded by a lipid envelope bearing glycoprotein spikes essential for host-cell entry.

Recent studies have focused on genomic mutations associated with Andes virus virulence and transmissibility. Comparative genomic analyses identified specific amino acid substitutions in glycoprotein and nonstructural protein regions that may contribute to enhanced human-to-human spread. Evidence for interpersonal transmission has been supported by epidemiological investigations and full-genome sequencing during outbreaks in Argentina, including the 2018 Epuyén outbreak, where sustained transmission chains required quarantine and intensive contact tracing measures. More recently, renewed global attention has emerged following suspected Andes virus transmission aboard a cruise ship in 2026, highlighting the continuing public health concern surrounding this uniquely transmissible orthohantavirus.