Hantavirus Outbreaks

Active, monitoring, and historical hantavirus incidents tracked by HORIZON. Each link opens the full ontology graph with authoritative WHO/ECDC case counts, corroborating articles, and the live event chronology.

2026: The MV Hondius Andes virus cluster is the dominant event. Full 2026 outbreak tracker → | MV Hondius incident page →

What counts as a hantavirus outbreak?

HORIZON defines an outbreak as a temporally and geographically clustered series of confirmed or strongly-suspected hantavirus cases that share a common exposure source, a common reservoir population, or a documented person-to-person transmission chain. Each tracked incident is curated from WHO Disease Outbreak News, ECDC Communicable Disease Threats Reports, PAHO weekly bulletins, national public-health authority statements, and peer-reviewed virological reports. Single sporadic cases are tracked on the articles archive; outbreaks aggregate the related cases into one ontology object with a stable URL.

How HORIZON tracks an outbreak from first signal to closure

1. Signal detection. The collection workers ingest from 65+ authoritative sources every 15 minutes. A new outbreak is flagged when the ontology engine sees three or more case reports tagged to the same country and serotype within a 14-day window, or when a Tier-1 source (WHO DON, ECDC CDTR) publishes an explicit outbreak notification.
2. Incident creation. Analysts review the flagged cluster and create an incident record with: name, code (slug), primary serotype, start date, status, and per-country expected case counts.
3. Live corroboration. Subsequent reports referencing the incident are auto-linked. The incident page lists the authoritative-source history showing each update with its NATO Admiralty Scale reliability and credibility rating.
4. Status transitions. Outbreaks move from active (case counts still rising) to monitoring (no new cases reported, surveillance ongoing) to resolved (two full incubation periods since the last confirmed case, with sustained absence of new signals).
5. Closure. Resolved outbreaks remain permanently accessible at their stable URL with a final summary, all corroborating articles archived for future analysis.

The 2026 outbreak landscape

2026 has been dominated by the MV Hondius Andes virus cluster — the first hantavirus outbreak linked to a cruise ship and the most geographically distributed hantavirus cluster in surveillance history. Returning passengers seeded incubating cases across multiple continents before becoming symptomatic, prompting coordinated national contact tracing in the UK, France, Germany, the Netherlands, Argentina, Chile, and beyond.

Beyond MV Hondius, 2026 has shown the expected seasonal patterns:

• Puumala virus seasonal activity in Finland, Sweden, Germany, and Belgium, driven by the autumn bank-vole cycle.
• Sin Nombre virus sporadic cases across the US Four Corners region, with the usual spring and early summer peak.
• Seoul virus pet-rat exposures in the UK and US, documented in rat-breeder communities.
• Hantaan virus activity in rural China and Korea, following the autumn harvest pattern.

Historical hantavirus outbreaks tracked by HORIZON

The HORIZON ontology includes a curated set of historically significant hantavirus clusters, used as comparators for current incidents:

• Four Corners 1993: the original Sin Nombre virus outbreak in the southwestern USA that led to the discovery of HPS as a clinical entity.
• El Bolsón 1996 (Argentina): the first documented Andes virus person-to-person cluster.
• Epuyén 2018-2019 (Argentina): a 34-case household Andes virus cluster in Patagonia that reshaped public-health guidance on ANDV contact tracing.
• Yosemite 2012 (USA): a cluster of HPS cases linked to visitor accommodation at Yosemite National Park; led to facility renovation and revised park-service guidance.
• Belgium 2017: a Puumala virus outbreak season with case counts exceeding 1,000 in a single year.
• Germany 2019: a Puumala virus year aligned with the oak/beech mast cycle.

How to use this index

Each card above links to a full incident page with:

• Live case, suspected, and death counts.
• Per-country breakdown.
• Authoritative-source history with NATO-scaled reliability.
• Vessel and exposure context where relevant.
• Corroborating article archive.
• Long-form explainer and FAQ for high-profile clusters (e.g. MV Hondius).

For machine-readable access to the incident data, see the open-data page or query the REST API endpoint directly. All HORIZON incident data is released under CC BY 4.0.

Open the live hantavirus outbreak map →