The M/V Hondius cluster is only the second documented event of sustained person-to-person Andes virus transmission ever recorded, and the first to occur outside South America.
The Andes virus outbreak linked to the M/V Hondius expedition cruise ship has continued to expand since WHO’s last situation report, with two additional confirmed cases reported from France and Spain and an inconclusive result pending in the United States. In its third Disease Outbreak News report on the cluster, published May 13, 2026, the World Health Organization confirmed a total of 11 cases — eight laboratory-confirmed, two probable, and one inconclusive — including three deaths, for a case fatality ratio of 27%. All cases are among passengers who traveled aboard the Dutch-flagged vessel, which departed Ushuaia, Argentina, on April 1.
WHO’s updated risk assessment characterizes the public health risk for those who were aboard the ship as moderate, while placing the global-level risk at low. For the general public — including people with no shipboard or close-contact exposure — the probability of infection is described as low.
New Cases in France, Spain, and the United States
Since the previous Disease Outbreak News on May 8, three additional cases have come to light. One confirmed case in France became symptomatic during repatriation. A confirmed case in Spain was detected upon arrival following repatriation but is currently asymptomatic and reported to be well. A third individual, repatriated to the United States, returned inconclusive laboratory results — one positive and one negative from two different laboratories — and is being retested. That person was sampled due to high-risk exposure to confirmed cases on board and is currently asymptomatic. WHO has engaged National IHR Focal Points in all affected countries to support international contact tracing.
Contact tracing efforts now span passengers who disembarked at multiple points along the voyage, including Saint Helena on April 24, Praia in Cabo Verde on May 6, and Tenerife in Spain’s Canary Islands on May 10 and 11. Passengers who shared flights with subsequently confirmed cases have also been identified and are being monitored by local health authorities in their respective countries.
Genomic Evidence Points to a Single Spillover
One of the most significant findings in this update is preliminary genomic sequencing data that strongly supports a single origin for the outbreak. Analysis of sequences from multiple cases shows a high degree of genetic similarity, with no more than one single nucleotide polymorphism difference per individual. This pattern, WHO stated, is consistent with a single zoonotic spillover event — or at most a very small number of closely related spillover events — rather than multiple independent introductions. Investigations into the travel history of the index case suggest possible exposure to rodents during birdwatching activities, though the precise circumstances remain under investigation in collaboration with Argentine and Chilean authorities.
The working hypothesis is that the first case acquired the infection on land prior to boarding, with subsequent human-to-human transmission occurring aboard the ship. The close living quarters, shared indoor spaces, prolonged exposure, and frequent interpersonal contact typical of expedition cruise travel are identified as factors that likely facilitated onboard spread.
Disembarkation Completed, Ship Now Sailing to the Netherlands
The operational response has reached a new phase. The M/V Hondius arrived in the Canary Islands on May 10, where disembarkation of passengers and most crew began. Passengers were repatriated to their home countries via specially arranged non-commercial flights, with WHO and partners supporting the logistics. The ship departed the Canary Islands on May 11 and is now sailing to the Netherlands with 25 remaining crew members on board, accompanied by two Dutch health workers providing monitoring and medical care as needed. WHO Director-General Dr. Tedros Adhanom Ghebreyesus traveled personally to the Canary Islands on May 9 to coordinate with Spanish national authorities and met with Spain’s Prime Minister on May 12.
What WHO Is Recommending
WHO’s guidance in this update reinforces and in some areas refines earlier recommendations. For high-risk contacts — defined to include intimate partners, household members, healthcare workers with unprotected exposure, and others with prolonged close indoor contact — WHO recommends active monitoring and home or facility quarantine for 42 days following last exposure, applying the precautionary principle given that infectiousness peaks in early illness and pre-symptomatic transmission cannot be entirely ruled out. Routine laboratory testing of contacts is not recommended for outbreak control purposes, and low-risk contacts are advised to conduct passive self-monitoring and seek medical evaluation only if symptoms develop.
In healthcare settings, WHO calls for standard and transmission-based precautions, airborne precautions during aerosol-generating procedures, and prompt transfer of suspected HPS cases to adequately equipped emergency or intensive care facilities. The agency reaffirmed that ribavirin, while active against hemorrhagic fever with renal syndrome, has not demonstrated effectiveness against hantavirus pulmonary syndrome and is not indicated. No licensed antiviral treatment or vaccine exists for HPS. WHO advised against any travel or trade restrictions beyond the movement restrictions applicable to identified high-risk contacts.
The spread of cases to France, Spain, and potentially the United States illustrates how quickly a rare pathogen can seed multiple jurisdictions through international air travel before it is identified, and underscores the continuing importance of the IHR contact tracing infrastructure now activated across more than a dozen countries. With disembarkation complete and the 42-day monitoring clock running, public health agencies in passenger home countries now carry the primary burden of surveillance through mid-June.
Sources and further reading:
Hantavirus cluster linked to cruise ship travel, Multi-country — WHO Disease Outbreak News, 13 May 2026
Transcript – Update on CDC’s Hantavirus Response – U.S. Centers for Disease Control and Prevention
Interim Guidance for Public Health Assessment and Management of People with Potential Exposure to Andes Virus – U.S. Centers for Disease Control and Prevention
Preliminary analysis of Orthohantavirus andesense virus sequences from a cruise-ship related cluster, May 2026 – Virological
“Super-Spreaders” and Person-to-Person Transmission of Andes Virus in Argentina (December 2, 2020) – New England Journal of Medicine