We are now two weeks into the most significant hantavirus outbreak in maritime history. The MV Hondius cluster — which began with a single evacuated passenger in April and has grown to 11 confirmed cases across 9 countries and 3 deaths — entered a new phase on May 13 with a flurry of simultaneous developments: a new confirmed case, the long-awaited source investigation report, a landmark peer-reviewed publication, and the first international regulatory response.
Here is the complete May 13 briefing.
Case Update: 11 Confirmed Cases, 9 Countries
Germany confirms the 11th global case.
Robert Koch Institute (RKI) announced this morning that one of three MV Hondius passengers previously flagged as symptomatic has tested positive for Andes virus. The patient — a resident of Munich — is hospitalised in stable condition at a Munich university hospital in isolation. Two remaining German contacts continue under active observation.
This brings the confirmed case total to:
| Country | Cases | Deaths |
|---|---|---|
| Netherlands | 2 | 0 |
| France | 2 | 0 |
| United Kingdom | 1 | 1 |
| Germany | 1 | 0 |
| Argentina (crew) | 1 | 0 |
| United States | 1 | 1 |
| Canada | 1 | 0 |
| New Zealand | 1 | 1 |
| TOTAL | 11 | 3 |
Spain Releases Rodent Investigation Report: The Source Is Confirmed
This is the biggest development of Week 2.
Spain’s Ministry of Health (Ministerio de Sanidad) published the official rodent investigation report for MV Hondius, concluding a shipboard environmental survey conducted by Spanish public health teams since the vessel arrived in Tenerife on May 9.
Key findings:
- Oligoryzomys longicaudatus (long-tailed pygmy rice rat) excreta detected in three below-deck storage areas
- All excreta samples tested RT-PCR positive for Andes virus
- No live rodents found — the animals likely died during the voyage or exited at an intermediate stop
- Morphological and genetic analysis confirmed the species matches the primary Andes virus reservoir in Patagonia
- Decontamination estimated complete by 20 May 2026
This report effectively closes the question of the primary infection source. The rodents entered the vessel during provisioning in Ushuaia, Argentina, and contaminated below-deck areas with infectious excreta. Passengers and crew who spent time in or near these areas were exposed via aerosol inhalation.
What remains unresolved: whether any subsequent person-to-person Andes virus transmission occurred among passengers — the WHO genome analysis (released May 12) found sequences too similar to distinguish single-source from P2P chains.
NEJM Publishes First Peer-Reviewed Hondius Case Series
The New England Journal of Medicine published a rapid communication today from investigators at Amsterdam UMC, Hôpital Bichat (Paris), and the Munich University Hospital:
“Andes Virus Hantavirus Pulmonary Syndrome in MV Hondius Passengers: A Rapid Case Series”
Key clinical findings from the first 7 confirmed cases:
- Median incubation period: 22 days (range 8–38 days)
- All 7 cases presented with prominent myalgia (thighs, hips, back) before respiratory symptoms
- Gastrointestinal prodrome (nausea, diarrhoea, abdominal pain) in 5 of 7 patients
- Time from symptom onset to ICU admission: median 4 days
- 2 of 7 required ECMO (extracorporeal membrane oxygenation)
- No clear HLA or immunological marker predicting severity in initial analysis
The 38-day incubation case in this series prompted the CDC and WHO to revise their monitoring recommendations from 21 to 45 days — a decision that has now affected thousands of Hondius contacts worldwide.
WHO Issues Interim Expedition Vessel Biosafety Guidance
The World Health Organization published “Interim Guidance: Biosafety Requirements for Expedition Vessels Operating in Hantavirus-Endemic Regions” — the first international standard of its kind.
Core requirements:
- Rodent-exclusion inspection within 48 hours of departure from any Patagonian port (Ushuaia, Punta Arenas, Puerto Montt)
- Mandatory ventilation assessment of all below-deck spaces before passenger boarding
- Symptom monitoring protocol: all passengers assessed at embarkation and daily by ship’s medical officer for first 14 days; any febrile illness with myalgia triggers PCR testing
- Contact list maintenance: complete passenger and crew manifest with emergency contact information must be held for 90 days post-voyage
- Medical evacuation pre-planning: written agreement with nearest ICU-level facility before departure from Antarctic waters
WHO notes these are interim requirements, applicable immediately, with a formal consultation period running through August 2026.
IAATO (International Association of Antarctica Tour Operators) confirmed in a brief statement that member operators would implement the WHO interim requirements for the remainder of the 2025–26 Antarctic season and all of the 2026–27 season.
Other May 13 Developments
Argentina: PAHO weekly bulletin reports the 2026 hantavirus season has reached 108 confirmed cases and 35 deaths. Neuquén and Río Negro provinces account for 61% of cases. The season is running 24% above the five-year average.
Chile: PAHO reports 11 confirmed 2026 hantavirus cases (3 deaths) in Chile, with the Aysén and Los Lagos regions designated high-risk zones.
Australia: Department of Health confirms all six MV Hondius passengers under active monitoring have completed 21 days of surveillance with no confirmed cases. Two highest-risk contacts are being extended to 45-day monitoring.
UK: UKHSA reports no new confirmed cases. 12 contacts placed on extended 45-day monitoring programme.
France (household cluster): Santé publique France continues investigating whether the two French Hondius cases — a couple who shared a cabin — represent person-to-person transmission or a shared environmental exposure. Results expected next week.
What to Watch in Week 3
The next 7 days will likely be defined by:
- France household cluster result — the clearest test case for P2P spread in this outbreak
- Germany remaining two contacts — both symptomatic, PCR pending; results expected within 48 hours
- First incubation-end dates — passengers with the shortest Hondius exposures will reach 21 days around May 16–18; new cases in this group would suggest longer-incubation exposures or P2P spread
- MV Hondius decontamination completion — scheduled for May 20; Spanish authorities to issue clearance report
- ECDC weekly surveillance update — Thursday, May 15
For live case tracking and country-by-country data, visit our global map →. Next update: May 14 evening.
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