Andes virüsü (ANDV): insandan insana bulaşan tek hantavirüs

Most hantaviruses are quiet. They cycle endlessly between rodents and their environment, jumping into a human only when someone disturbs contaminated dust in a barn or a back-country cabin. Once inside a person, they cause disease, sometimes severe disease — but they do not keep moving. The chain of transmission stops at the patient.

The Andes virus does not respect that rule. First identified in southern Argentina in the late 1990s, ANDV is the only hantavirus with peer-reviewed evidence of person-to-person transmission. That single biological quirk is why a cruise-ship cluster called MV Hondius triggered a multi-country WHO alert in May 2026 instead of being treated as a contained environmental exposure.

1. Where the virus came from

The Andes virus was isolated in 1995 from a deceased patient in El Bolsón, in the Patagonian foothills of Argentina. The reservoir host is the long-tailed pygmy rice rat (Oligoryzomys longicaudatus), a small native rodent that thrives in the temperate forests and grasslands of southern Chile and Argentina and shows no obvious illness from the infection.

Genetic studies place ANDV in the Sigmodontinae-borne lineage of New World hantaviruses, sister to Sin Nombre virus from North America but distinct enough that immunity to one does not necessarily protect against the other. Strain variants have since been reported across much of Argentina, Chile, Bolivia, and Uruguay; smaller clusters have been described in Peru and Brazil.

2. The El Bolsón cluster, 1996

In late 1996 the Argentine Ministry of Health investigated an outbreak in El Bolsón that included clusters in households with no shared environmental exposure. The pattern that finally cracked the case was epidemiological: secondary cases occurred in spouses, nurses, and physicians who had cared for patients several days before symptom onset. Sequencing later confirmed identical viral genomes across pairs of cases linked only by close contact.

That investigation, published in Emerging Infectious Diseases (Wells et al., 1997), is the foundational reference cited by every major outbreak report since, including the WHO's 2026 DON-599 notification.

3. How person-to-person transmission probably works

Direct comparative work has been hard because cases are rare. The prevailing hypothesis, based on viral RNA recovery from saliva and respiratory secretions in late prodromal patients, is that ANDV achieves limited respiratory or contact transmission during the viremic days immediately before and after symptom onset. Studies of Andes-positive household contacts have estimated secondary attack rates in the single digits, much lower than influenza, but high enough to drive small chains of transmission in close quarters such as a single home or a healthcare cubicle.

4. Clinical course

ANDV causes hantavirus pulmonary syndrome, the same clinical picture produced by Sin Nombre virus and other New World hantaviruses. The defining feature is a deceptively quiet prodrome of fever, myalgia, and gastrointestinal symptoms followed by abrupt non-cardiogenic pulmonary edema, profound hypotension, and shock. Unlike most respiratory infections, the lungs of an HPS patient fill with protein-rich fluid not because the heart is failing but because viral damage to capillary endothelium causes massive vascular leakage.

The case-fatality rate for laboratory-confirmed ANDV infection has ranged from 30% to 50% across published series, clustering around 35% in well-resourced settings with early ICU access. In the MV Hondius cluster, three deaths among the first seven confirmed cases is consistent with that historical range.

5. Diagnosis and treatment

Diagnosis relies on a clinical suspicion plus laboratory confirmation: IgM serology, RT-PCR on serum or respiratory specimens, and increasingly genome sequencing for outbreak investigation. There is no licensed antiviral therapy. Ribavirin has been studied but evidence remains equivocal for HPS. Care is supportive: aggressive ICU management with mechanical ventilation, vasopressors, and in selected centers venoarterial ECMO, which has been associated with markedly better survival in case series from Chile and the United States.

6. Vaccines and post-exposure prophylaxis

No ANDV vaccine is licensed anywhere as of May 2026. A DNA-vaccine candidate developed by USAMRIID and partners has reached early-phase human studies. Convalescent immune-plasma protocols, monoclonal antibodies, and small-molecule polymerase inhibitors are all in preclinical or very early clinical pipelines. None of these are likely to change the management of the current outbreak in the short term.

7. What sets the 2026 outbreak apart

Three things make MV Hondius unusual relative to historical ANDV outbreaks:

• Geography. Confirmed cases have appeared in Europe, Singapore, and the United States — far outside the virus's natural reservoir range. This reflects the cruise ship as a vector, not a change in the virus.
• Multinational contact tracing. Twelve or more countries are simultaneously running passenger tracebacks. That is unprecedented for ANDV.
• Public attention. Search interest has spiked worldwide. Misinformation will travel further than the virus, which is part of why a sober reference like this site exists.

8. What we are watching next

Three indicators will determine whether this remains a contained cluster or grows into something larger:

1. Tertiary cases. Any case with no link to the ship or to a known passenger would suggest broader transmission.
2. Healthcare-worker cases. Historically the strongest evidence of contagiousness. None confirmed yet.
3. Genomic divergence. Comparing the MV Hondius strain to historical ANDV sequences will tell us whether the virus has changed in any relevant way.

The live tracker updates as official sources post new information. For the day-by-day timeline of the outbreak see our MV Hondius dossier.