⚡ 2026 Situation — MV Hondius
An Andes virus cluster linked to the MV Hondius expedition vessel is being monitored by WHO, ECDC and PAHO. There are 5 confirmed and 3 suspected cases across 8 nationalities. Contacts are under a 45-day surveillance window. No confirmed local transmission outside the vessel environment.
Andes Virus Key Facts
| First isolated | Argentina, 1995 |
| Reservoir host | Long-tailed pygmy rice rat (Oligoryzomys longicaudatus) |
| Geographic range | Patagonia — Argentina, Chile; southern South America |
| Disease caused | Hantavirus Pulmonary Syndrome (HPS) |
| Case fatality rate | 35–40% |
| Person-to-person | Confirmed — unique among hantaviruses |
| WHO classification | Priority pathogen under surveillance |
| Current situation | Active monitoring — MV Hondius 2026 cluster |
Why Andes Virus Is Unique
Of more than 50 hantavirus species identified globally, only Andes virus has reproducibly demonstrated transmission from one infected person to another. This behaviour — well-documented since the late 1990s in Argentina and Chile — fundamentally distinguishes it from all other hantaviruses and makes it a focus of special attention for international public health authorities.
WHO classifies Andes virus as a priority pathogen under continuous surveillance. ECDC and CDC maintain updated response protocols including full PPE use for healthcare workers caring for HPS patients with suspected Andes virus.
Transmission Routes
Primary (rodent-to-human)
Risk: HighInhalation of aerosolised virus from the droppings, urine or saliva of infected long-tailed pygmy rice rats. Typically occurs in rural or outdoor settings in Patagonia.
Person-to-person (unique)
Risk: MediumConfirmed via close respiratory contact with a severely ill HPS patient. Only documented for Andes virus — not observed for any other hantavirus strain globally.
Direct contact
Risk: LowTouching infected rodents or their nesting materials without adequate protection. Risk without inhalation component is considered lower.
Casual contact
Risk: NoneAndes virus is NOT transmitted by casual social contact, shaking hands, or being in the same room as an ambulatory HPS patient.
Geographic Distribution
Andes virus circulates in a geographically defined area encompassing primarily Argentine and Chilean Patagonia, although sporadic cases have been detected in more northern zones of both countries. The approximate northern limit of the reservoir distribution (the long-tailed pygmy rice rat, Oligoryzomys longicaudatus) determines the natural endemic area.
Argentine provinces with the highest historical case burden include Río Negro, Chubut, Neuquén, Santa Cruz and Tierra del Fuego. In Chile, southern regions such as Los Lagos, Aysén and Magallanes register the most activity.
Higher-risk areas
🇦🇷 Argentina
Río Negro · Chubut · Neuquén · Tierra del Fuego
🇨🇱 Chile
Los Lagos · Aysén · Magallanes · Biobío
Risk is highest in rural, agricultural and camping areas within the indicated regions.
Symptoms of Andes Virus Infection
Andes virus causes HPS with an incubation period of 1 to 4 weeks after exposure. The clinical presentation is similar to other HPS strains, with some differential characteristics such as more marked early thrombocytopenia in some cases.
Prodromal phase (1–4 weeks)
- Fever and chills
- Fatigue and myalgia
- Nausea, abdominal pain
- No initial respiratory symptoms
Cardiopulmonary phase (days 5–10)
- Sudden dyspnoea
- Severe hypoxia
- Pulmonary oedema
- Possible cardiogenic shock
Convalescent phase
- Gradual improvement
- Persistent fatigue
- Recovery possible with ICU
- 6–12 week follow-up
Frequently Asked Questions
What makes Andes virus different from other hantaviruses?
Andes virus is the only hantavirus strain confirmed to transmit from person to person. All other hantaviruses are transmitted exclusively from infected rodents to humans. This unique characteristic places Andes virus under heightened international surveillance and makes it a priority pathogen for public health preparedness.
How is Andes virus transmitted between people?
Person-to-person transmission of Andes virus has been documented through close respiratory contact with severely ill HPS patients — typically household contacts or healthcare workers without adequate PPE. It is not transmitted through casual contact, and the risk to the general public from an infected individual remains very low.
Where is Andes virus found?
Andes virus circulates primarily in Patagonia, particularly in southern Argentina and Chile. Its rodent reservoir, the long-tailed pygmy rice rat (Oligoryzomys longicaudatus), is endemic to these areas. Most human cases occur in rural and semi-rural settings, particularly among agricultural workers, campers and people involved in outdoor activities.
What is the MV Hondius cluster?
In 2026, an Andes virus cluster was identified aboard the MV Hondius, an expedition vessel operating in Antarctic and Patagonian waters. With 5 confirmed cases, 3 suspected cases and 3 deaths across 8 nationalities, this is one of the most internationally significant Andes virus events on record. ECDC, WHO and PAHO are monitoring all contacts for 45 days post-disembarkation.
Can Andes virus spread outside South America?
The primary rodent reservoir (Oligoryzomys longicaudatus) is geographically restricted to Patagonia, so sustained rodent-to-human transmission outside this region is extremely unlikely. However, the MV Hondius cluster illustrates that person-to-person transmission can carry the virus to other continents via international travellers, making surveillance and contact tracing outside the Americas relevant.
Is there a vaccine for Andes virus?
As of 2026, there is no commercially available vaccine for Andes virus or any other hantavirus. Several vaccine candidates are under research, including recombinant protein and DNA-based approaches, but none have completed Phase III clinical trials. Treatment remains supportive (ICU care) with no approved antiviral.
Sources
Medical disclaimer: This page is for informational purposes only and does not replace professional medical advice. If you suspect hantavirus infection, seek emergency care immediately.