Hantavirus Global Situational Briefing — May 20, 2026

The Rotterdam decontamination of MV Hondius entered its third day as the ECDC cluster count held at 12 cases and 3 deaths. Two US passengers at the Nebraska National Quarantine Unit received the first federal quarantine orders signed under the Public Health Service Act. Spain reported a provisional positive among its Gómez Ulla evacuees. France's ECMO patient remains critical. The US also recorded two unrelated domestic hantavirus events — a fatal Sin Nombre case in Colorado and a suspected locally acquired case at a New York high school.

MV Hondius: decontamination under way in Rotterdam

EWS Group, the Dutch specialist firm contracted by Oceanwide Expeditions, began full-vessel decontamination of MV Hondius at Rotterdam's Calandsteiger 7 on May 18, with the process expected to take three to four days 1. As of May 19, 25 crew members and 2 ship medics remained aboard under RIVM-supervised quarantine, while hazmat-suited technicians removed biological samples and equipment. Separately, 2 Dutch crew members were in home quarantine, and 38 Filipino crew — all confirmed PCR-negative by the Department of Migrant Workers — remained in 42-day precautionary quarantine in Netherlands facilities.

The vessel arrived at Calandsteiger 7 on May 18 after passengers completed staggered disembarkation via Tenerife. A Spanish-language report noted a planned June cruise on MV Hondius's schedule, though Oceanwide's earlier public communications stated voyages were suspended through at least June 1, conditional on the ship passing public health inspection before any resumption.

Cluster totals: 12 cases, 3 deaths; ECDC Week 21 still pending

The ECDC cluster count as of May 17 stands at 12 cases total — 9 confirmed, 2 probable, 1 inconclusive — across 23+ countries, with 3 deaths (CFR ~25%) 2. No new deaths have been reported since May 2, a 17-day window that now spans the entire Rotterdam arrival and decontamination phase.

ECDC's Communicable Disease Threats Report for Week 21 (covering May 19–25) was not published as of the time of this briefing. WHO DON-602 — expected to document the Rotterdam arrival, the Canada case confirmation, and the Illinois Winnebago closure — also remains pending.

The genome, sequenced by ANDV/Switzerland/Hu-3337/2026 and posted to Pathoplexus (509 sequences as of May 18), shows ≤1 SNP divergence from existing South American ANDV strains. ECDC's Andreas Hoefer confirmed at a May briefing: "At the moment there is no data to suggest this virus is behaving any differently in transmissibility or severity. All sequences to date are virtually identical." 3

Spain: second provisional positive among Gómez Ulla evacuees

One of the 14 Spanish nationals quarantined at Hospital Central de la Defensa Gómez Ulla in Madrid tested provisionally positive for hantavirus, Spanish health authorities confirmed — becoming the 12th case in the ECDC count. The other 13 Spanish evacuees tested negative 4. The patient presented with low-grade fever and mild respiratory symptoms and remained clinically stable with no evident deterioration. As of the hanta-tracker.app aggregation on May 19, the patient was described as asymptomatic at time of confirmation.

Spain's Prime Minister Pedro Sánchez appeared at a joint press conference with WHO Director-General Tedros Adhanom Ghebreyesus on May 12 and declared the evacuation operation a "success." Tedros called it a model for international solidarity. The patient who tested positive is separate from the first confirmed Spanish case, a 70-year-old man who was "recovering favorably" and approaching discharge earlier in the week.

France: ECMO patient remains critical, no change

The French passenger, a 65-year-old woman, continues on extracorporeal membrane oxygenation (ECMO) at Hôpital Bichat AP-HP in Paris. As of the latest tracker aggregation on May 19-20, clinical status is unchanged — still critically ill 5. French public health authorities reported all 26 close contacts PCR-negative, and full genome sequencing of the French patient's sample showed no mutations conferring increased transmissibility.

Canada: Yukon case confirmed, travel partner negative

PHAC (Public Health Agency of Canada) has confirmed Canada's first Andes hantavirus case: a Yukon resident in their 70s who traveled on MV Hondius and is now isolating in Victoria, British Columbia, with stable symptoms. British Columbia's senior health officer Dr. Bonnie Henry said the patient "developed mild symptoms and tested presumptive positive" on May 16, with NML confirmation following. Of six Canadians who traveled on MV Hondius, none of the other five have tested positive 6.

United States: federal quarantine orders issued; two domestic cases unrelated to outbreak

Nebraska: first federal quarantine orders

CDC issued quarantine orders on May 18-19 for two passengers at the Nebraska National Quarantine Unit at the University of Nebraska Medical Center in Omaha, signed by CDC's Acting Director under the Public Health Service Act and implementing regulations (42 CFR parts 70 and 71). All 18 repatriated passengers had been requested to remain through May 31 — the 21-day monitoring mark — after some declined informal requests to stay 1. The formal quarantine orders represent the first use of federal authority in this outbreak, and CDC confirmed the measure is being used "as necessary to protect communities."

As of the 42-day monitoring window (beginning May 11, ending June 22), there are zero confirmed US cases linked to the Hondius. CDC is monitoring approximately 41 people across 12 states (AZ, CA, GA, KS, MD, MN, NE, NJ, TX, UT, VA, WA). A fourth King County, Washington resident was added to monitoring as recently as May 19.

The Illinois Winnebago County case — initially feared as an Andes exposure — returned a CDC confirmatory negative on May 19 and is now closed.

Colorado: fatal Sin Nombre case unrelated to ship

The Colorado Department of Public Health and Environment confirmed that a Douglas County adult died of hantavirus in a case not linked to MV Hondius. Preliminary evidence points to local rodent exposure; the strain involved is Sin Nombre virus, which does not spread person-to-person 6. This is the first Sin Nombre HPS fatality reported publicly in 2026.

New York: suspected locally acquired case at Geneva High School

New York State health officials are investigating a suspected hantavirus case in Ontario County involving a Geneva High School student, confirmed by the Geneva City School District on May 15-16 7. Health officials stated the patient poses no risk to classmates and the case is not linked to the cruise ship. Local rodent exposure is the suspected route.

Radboudumc protocol breach: 12 staff in 6-week quarantine

Radboud University Medical Centre (Radboudumc) in Nijmegen, Netherlands, acknowledged that 12 hospital employees were placed in precautionary six-week quarantine after a protocol breach involving the MV Hondius patient admitted on May 7. Standard blood-draw procedures were followed instead of the stricter biosafety protocol required for hantavirus; incorrect urine disposal procedures were also used 8. The hospital's board chair Bertine Lahuis said: "We regret that this has happened at our university medical center. We will carefully investigate the course of events to learn from this and to prevent it from happening in the future." Dutch healthcare unions — including CNV — called the lapse "incomprehensible." All 12 employees are under quarantine; the risk of infection is assessed as low.

Americas endemic surveillance

Argentina: The most recent Boletín Epidemiológico Nacional (BEN SE17, through May 12) confirmed 102 cases, 32 deaths (CFR 31.4%) for the 2025-2026 season. An ANLIS Malbrán team remained on-site in Ushuaia investigating the spillover origin that likely seeded the Hondius cluster. The BEN SE18 update was expected around May 19; no published data was available at briefing time 9.

Chile: 41 cases, 14 deaths (CFR 34%) through the latest reporting period; Aysén cold-season alert active.

Bolivia: Infectologist Fernando Molina confirmed 18+ cases nationally in 2026, with 4 cases in Tarija department (border with Argentina) triggering a departmental sanitary alert. These are endemic Andes-strain transmissions distinct from the Hondius cluster 10.

Brazil: Distrito Federal suspects under evaluation; cumulative 2013-2026 total exceeds 860 cases / 341 deaths.

Watch items for May 21

WHO DON-602: Overdue — expected to formally document the Rotterdam arrival, Canada case, and Winnebago closure.
ECDC CDTR Week 21: Covers May 19–25; first edition that may incorporate decontamination status and Spain's second provisional case.
Argentina BEN SE18: Expected to have been released around May 19; publication or data from ANLIS Malbrán anticipated.
Nebraska quarantine challenge: Whether the two passengers subject to federal quarantine orders contest them legally; monitoring window ends June 22.
MV Hondius decontamination: EWS Group's 3-4 day timeline puts completion around May 21-22; RIVM inspection determines whether vessel returns to service before June 1.
France ECMO patient: Any change in clinical status — she has been on mechanical lung support for over a week with no improvement reported.