Hantavirus Global Situational Briefing — June 4, 2026

The Andes virus cluster from MV Hondius holds at 13 cases and 3 deaths for a ninth consecutive day without new infection — but Argentina reports a fresh domestic case in Bariloche, and its Health Ministry has dispatched teams to Ushuaia to trap and test rodents at the outbreak's geographic origin. In the United States, health departments confirm 24/7 home surveillance for passengers who left Nebraska federal quarantine, a level of monitoring public health experts say exceeds anything routinely applied to infectious disease exposures.

The global case tally from the MV Hondius voyage remains at 13 — 11 confirmed and 2 probable — with 3 deaths, all occurring before May 2.1 No new case has been detected since May 26. The MV Hondius itself was cleared by Rotterdam's GGD on May 30 and remains moored at Waalhaven 7 ahead of its scheduled June 13 restart to Svalbard.

ECDC's homepage continues to note that "further cases are expected among returning passengers and crew due to the Andes hantavirus incubation period and potential on-board exposure," and assesses the risk to the EU/EEA general population as "very low."2 No new ECDC rapid risk assessment has been published since CDTR Week 22 (May 29).

Five of the 18 Americans housed at Nebraska's National Quarantine Unit have returned to their home states. Thirteen remain at the facility.3 According to CDC, all people remain symptom-free.

The home-monitoring arrangements now confirmed publicly go substantially beyond standard practice. New York State's health department told MedPage Today that passengers who returned to New York will have "someone on site 24 hours a day until June 22." Oregon's state health department confirmed "24/7 monitoring in place" as required by federal conditions.4 Arizona and California had not publicly confirmed their arrangements as of Wednesday.

MedPage Today characterized the approach as "unusually strict" compared to the monitoring applied to passengers who disembarked in April — those individuals were followed up by state and local health departments but were not subject to continuous physical surveillance. The same piece drew a parallel with the Trump administration's handling of Ebola exposures, where federal officials also planned unusually stringent containment measures that drew criticism from the public health community.4

Two of the three New York State passengers were transported home via non-commercial flights; both are quarantining outside New York City. A third New York passenger is completing the full 42-day period at Nebraska. Monitoring for the May 11 disembarkation cohort ends June 22.

The 65-year-old French woman on ECMO at Hôpital Bichat AP-HP enters approximately her 27th or 28th day on extracorporeal membrane oxygenation with no confirmed clinical update since "no further deterioration as of May 28" — now seven days without any public communication. France's 26 monitored contacts remain PCR-negative and are tested three times weekly. All 26 remain in mandatory hospital isolation.5

Spain's two confirmed cases remain stable. Spain's asymptomatic contacts are approaching June 7, the approximate date at which they become eligible for a transition from hospital isolation to a 14-day home phase.

The Netherlands received favipiravir tablets from Japan through the EU–Japan emergency procurement dispatched May 28. EC procurement for additional doses is ongoing.

A 45-year-old man was admitted to the Ramón Carrillo Hospital intensive care unit in Bariloche (Río Negro Province) after presenting with fever, diarrhoea, and body aches. The patient tested positive for hantavirus and was transferred to ICU. His wife and son have been placed in preventive isolation. Health authorities are investigating the source of infection; the man had recently travelled to the northern provinces of Jujuy and Salta. Rodrigo Bustamante, Director of Epidemiology at the hospital, told the Río Negro newspaper: "It has been five days since the onset of symptoms and we are entering the most critical period in which patients can become unwell."6

This case is independent of the MV Hondius cluster. The Argentine Health Ministry has recorded 45 confirmed hantavirus cases so far in calendar 2026, and 101 cases for the full epidemiological year that runs June-to-June — roughly double the 57 recorded in the same period a year prior. Raúl González Ittig, a biologist and researcher at the National University of Córdoba, told the Buenos Aires Times that the elevated figures reflect "isolated cases," not an outbreak: "Argentina has hantavirus cases every year."6 Cases this season have been confirmed in Chubut, Río Negro, and Jujuy — none in Tierra del Fuego.

Argentina's Health Ministry confirmed it is sending technical teams to Ushuaia to conduct rodent capture and analysis "in areas linked to the movements of the cases, and to detect the possible presence of the virus in natural reservoirs."6 The Andes strain has not been detected in Tierra del Fuego Province since mandatory disease notification began in 1996, and the Ministry noted that the Dutch couple who died had traveled through Chile, Uruguay, and Argentina before boarding MV Hondius on April 1 — leaving the index exposure site formally undetermined.

The survey is the first structured rodent-sampling effort directly tied to the cruise ship outbreak. Earlier field data had placed likely exposure at a shore excursion in Patagonian Argentina; WHO's DON 604 ruled out a specific Chilean excursion site as the exposure venue. Results from the Ushuaia survey are not yet available.

Three Lancet papers published in the 48 hours before this briefing have begun to transform the MV Hondius outbreak from a live emergency into a documented scientific record: a commentary by Tony Kirby in Lancet Infectious Diseases summarizing the first peer-reviewed case count; a Lancet Regional Health – Europe piece calling for Andes-virus-capable laboratory surveillance across all EU national reference laboratories; and a second Lancet Regional Health – Europe paper using the Hondius cluster as a statistical signal to argue that Argentina's 106 severe ANDV cases in the 2025-26 season represent an undercount of true burden.7

The Oxford/ISARIC clinical observational study has been running for 14 days with no interim publication.

NIH's CREID network — which included at least one dedicated Andes hantavirus laboratory — was cancelled in June 2025 with approximately $82 million in grant terminations. The timing of that cancellation, now coinciding with the first major ANDV human-to-human transmission event in a decade, has drawn sustained attention from CIDRAP and Wired.8