HORIZON · Hantavirus Tracker

Hantavirus 2026 Outbreak Timeline

A chronological record of every major hantavirus event in 2026, sourced exclusively from authoritative publications: WHO Disease Outbreak News, CDC Health Alert Network, ECDC Communicable Disease Threats Report, PAHO Epidemiological Alerts, national health ministries, and peer-reviewed literature. Every date carries a source citation. This timeline covers the MV Hondius Andes virus cluster and ongoing endemic hantavirus activity worldwide.

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2026 MV Hondius outbreak timeline

The 2026 MV Hondius cluster is the defining hantavirus event of 2026: the first documented large-scale Andes virus (ANDV) exposure in a closed-vessel environment. The following events are sourced from WHO DON 600, PAHO Alert 2026-03-25, ECDC, CDC, RIVM, UKHSA, and the Oxford Kraemer Lab individual-level line list (CC0).

  1. MV Hondius departs on an Antarctic expedition cruise via Ushuaia, Tierra del Fuego, Argentina. Passengers participate in wildlife excursions on or near the Argentine steppe, the primary ANDV-endemic zone of Patagonia. The exposure window for the index cohort is assessed to fall in this period. ANDV is endemic in the rodent Oligoryzomys longicaudatus (long-tailed pygmy rice rat) throughout southern Argentina and Chile.

    Source: PAHO Epidemiological Alert 2026-03-25; WHO DON 600; ECDC CDTR.

  2. PAHO Epidemiological Alert 2026-03-25 issued. PAHO alerts member states to an emerging Andes virus cluster linked to MV Hondius passengers. Argentina Ministerio de Salud confirms the first laboratory-confirmed case. Index case with PCR confirmation. Argentina activates national surveillance protocols.

    Source: PAHO Epidemiological Alert 2026-03-25 (A1/1 NATO — PAHO is the highest-tier regional authority for the Americas).

  3. MV Hondius voyage concludes. Passengers repatriate to countries of origin across Europe, North America, and Australasia. Symptom onset documented across the cohort: the Oxford Kraemer Lab individual-level line list records onset dates from 6 April to 7 May 2026, consistent with ANDV's 1–8 week incubation after aerosolised exposure.

    National health authorities in the Netherlands (RIVM), France (SPF France), Spain, and the United Kingdom (UKHSA) activate case-finding among MV Hondius passengers. WHO Regional Offices (EURO, AMRO) notified. Multi-country coordination initiated.

    Sources: Oxford Kraemer Lab MV Hondius ANDV line list (CC0, updated in real time); RIVM (NATO A2); SPF France (NATO A2); UKHSA (NATO A2).

  4. WHO Disease Outbreak News 2026-DON600 published. WHO formally notifies the international community of the multi-country Andes virus cluster.

    • Confirmed cases: 28 (at initial DON600 publication)
    • Countries with confirmed/suspected cases: 11
    • Serotype: Andes virus (ANDV), confirmed by PCR
    • Exposure window: Ushuaia, Tierra del Fuego, Argentina
    • Transmission: Environmental (rodent excreta) during land excursions. Person-to-person transmission not ruled out for some cases (ANDV is the only orthohantavirus with documented P2P capability).

    Source: WHO DON 600 (NATO A1 — WHO Disease Outbreak News is the gold standard for confirmed multi-country outbreak notifications).

  5. CDC confirms US passengers among those exposed. CDC Health Alert Network (HAN) guidance issued for US clinicians. US repatriation flights coordinated from disembarkation ports. UKHSA confirms British nationals among monitored contacts.

    Oxford Kraemer Lab individual-level line list updated: nationality breakdown includes Spain, Netherlands, France, UK, Canada, US, Ireland, South Africa, Germany, and others.

    Sources: CDC HAN (NATO A1); UKHSA (NATO A2); Oxford Kraemer Lab line list (CC0).

  6. UKHSA blog post published: "What you need to know about the hantavirus outbreak linked to the Dutch cruise ship." UKHSA confirms the MV Hondius is a Netherlands-flagged vessel; clarifies that the passenger exposure was environmental, not onboard transmission, and provides clinical guidance for UK clinicians seeing returning travellers with compatible symptoms.

    Source: UKHSA blog (NATO A2).

  7. Active surveillance continuing. All repatriated passengers and crew within the incubation window remain under active monitoring by national health authorities. WHO, ECDC, PAHO, and national ministries are co-ordinating.

    HORIZON is ingesting case updates every 15 minutes from 65+ authoritative sources. Authoritative case counts: see the live dashboard and the MV Hondius incident page.

    Source: HORIZON live ingest pipeline (WHO, ECDC, PAHO, RIVM, SPF France, UKHSA, Argentina MSAL, Oxford Kraemer Lab).

2026 endemic hantavirus activity (non-MV Hondius)

The MV Hondius cluster is unusual but not indicative of a global hantavirus surge. Endemic activity in 2026 is consistent with historical patterns.

Puumala virus (PUUV) — Europe

Finland has the highest hantavirus notification rate in Europe: 14.5 per 100,000 population per year (ECDC Annual Epidemiological Report 2023). 2026 activity is monitored by THL (National Institute for Health and Welfare, NATO A1). Peak season is July–August following mast years in the bank vole (Myodes glareolus) population. Sweden (FHM, sorkfeber in Norrland and Ångermanland), Norway (FHI, Innlandet region), Germany, France (Ardennes, Champagne-Ardenne), and Belgium report seasonal PUUV cases. ECDC CDTR covers all EU activity weekly.

Data: Puumala virus serotype page, Finland country page, Sweden country page.

Andes virus (ANDV) — South America (endemic)

Argentina is the global ANDV epicentre outside the MV Hondius cluster. The Argentine Ministerio de Salud publishes the Boletín Epidemiológico Nacional (BEN), ingested by HORIZON weekly (NATO B2). Endemic provinces: Patagonia (Río Negro, Neuquén, Chubut, Santa Cruz), Buenos Aires province (pampas), and Tierra del Fuego. Chile, Bolivia (Beni, Pando), Brazil (Juquitiba and Araraquara genotypes in São Paulo), and Paraguay also report regular ANDV cases.

Data: Argentina country page, Chile country page, Brazil country page.

Hantaan virus (HTNV) and Seoul virus (SEOV) — East Asia

China, South Korea, and Japan continue to report Hantaan virus (HFRS, high CFR) and Seoul virus (HFRS, lower CFR) cases. Seoul virus circulates globally via Rattus norvegicus and Rattus rattus wherever rat populations exist. HORIZON ingests reports from China CDC (when accessible), Japan NIID, NCBI GenBank (new HTNV/SEOV sequences with reldate=14), and WHO WPRO.

Understanding the timeline: confirmed vs monitored

A word on case counts that appear in other trackers. For the MV Hondius cluster, some sites show totals of 100–170+ "cases." These typically include large "monitoring" categories of passengers who were on the ship but have not developed symptoms. HORIZON follows WHO DON 600 terminology:

This is why HORIZON's confirmed case count differs from the 170+ figures seen on mapping sites: we count confirmed and suspected cases per WHO DON 600, not the full monitoring cohort of all passengers.

Live chronology and event feed

HORIZON's machine-readable event feed is updated every 15 minutes:

Related pages

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