Overview of hantavirus
Hantaviruses are a family of rodent-borne RNA viruses in the genus Orthohantavirus (family Hantaviridae). Different hantavirus species cause two distinct human syndromes: hemorrhagic fever with renal syndrome (HFRS) in Asia and Europe, and hantavirus pulmonary syndrome — also called hantavirus cardiopulmonary syndrome (HPS/HCPS) — in the Americas. The 2026 MV Hondius cluster has refocused public-health attention on Andes orthohantavirus (ANDV), the only hantavirus with confirmed person-to-person spread.
What is a hantavirus?
Hantaviruses are enveloped, single-stranded, negative-sense RNA viruses with a tripartite genome. They are spread primarily through inhalation of aerosolized rodent excreta (urine, feces, saliva). Unlike most rodent-borne pathogens, hantaviruses do not require an arthropod vector and are not transmitted by fleas, ticks or mosquitoes. Each hantavirus species has co-evolved with a specific rodent reservoir, meaning the geographic distribution of human disease tracks closely with the range of the host rodent.
The two clinical syndromes
HFRS predominates in Eurasia and is caused by Hantaan, Seoul, Puumala and Dobrava-Belgrade viruses. It produces fever, hypotension, oliguria and renal failure with case fatality from less than 1% (Puumala) to 10-15% (Hantaan). HPS is endemic to the Americas and is caused by Sin Nombre virus (North America), Andes virus (Southern Cone), Bayou, Black Creek Canal and others. HPS is dominated by non-cardiogenic pulmonary edema and cardiogenic shock, with overall case fatality of 35-50% depending on the viral species and access to ICU care.
Why ANDV in 2026
ANDV is endemic to Argentina and Chile and is unique among hantaviruses because it is documented to spread directly from person to person — most famously during the 1996 El Bolsón cluster and the 2018-2019 Epuyén outbreak. The 2026 MV Hondius outbreak, originating on an expedition cruise in the South Atlantic and seeded forward via a charter evacuation flight to Johannesburg, has put ANDV at the center of global hantavirus surveillance. Because the virus can chain through close contacts, secondary case clusters can emerge thousands of kilometers from the original exposure.
Burden of disease
Roughly 150,000 to 200,000 hantavirus infections are reported worldwide each year, with the great majority of confirmed cases occurring in mainland China (HFRS, Hantaan and Seoul viruses). In the Americas, several hundred HPS cases are reported annually across Argentina, Chile, Brazil, the United States and Canada combined. Underreporting is substantial in rural and indigenous communities, and serological studies in the Southern Cone suggest seroprevalence of 1-13% in highly exposed populations.
- •Hantaviruses are RNA viruses spread mainly by inhaling aerosolized rodent excreta
- •Each species co-evolved with one rodent reservoir, dictating its geography
- •HFRS is the Asian/European form; HPS is the Americas form
- •Case fatality for HPS is 35-50%, with ANDV at the high end
- •ANDV is the only hantavirus with documented person-to-person transmission
FAQ
Is hantavirus contagious between people?+
Most hantaviruses are not. The Andes orthohantavirus (ANDV) found in Argentina and Chile is the only species with documented person-to-person transmission, particularly in household and healthcare settings.
Is there a hantavirus vaccine?+
Inactivated HFRS vaccines (Hantavax) are licensed in South Korea and China for Hantaan/Seoul viruses. No vaccine is currently approved for HPS or ANDV; several candidates are in early clinical trials.