Hantavirus outbreak associated with cruise ship journeys across multiple countries

On May 2, 2026, the WHO was informed by the UK NFP about a cluster of severe acute respiratory illnesses on the MV Hondius, which included two deaths and one critically ill passenger. By May 13, the count stood at 11 cases—eight confirmed, one inconclusive, and two probable—along with three deaths (two confirmed, one probable). Since the last report on May 8, new data highlighted a confirmed case from France who showed symptoms during repatriation, a confirmed case from Spain, who tested upon arrival and is currently asymptomatic, and one inconclusive case repatriated to the USA, who is also asymptomatic but has mixed lab results (one positive, one negative) and is undergoing retesting. All confirmed cases relate directly to ANDV infection.

The initial hypothesis suggests the first case likely contracted the virus before boarding, possibly through exposure on land. Investigations are ongoing to clarify the circumstances and source of the outbreak, in collaboration with authorities from Argentina and Chile. Current evidence indicates there was human-to-human transmission while aboard. Genetic analysis shows a near-identical sequence among different cases, supporting this theory.

The outbreak response involves a coordinated international effort, including epidemiological investigations, case isolation, medical evacuations, lab testing, and contact tracing. Recommendations may be revised as new evidence becomes available. Contacts of all hantavirus cases linked to the cruise ship are being tracked. This includes passengers who disembarked in Saint Helena, Cabo Verde, and Tenerife. A noticeable effort is being made to monitor those who may have traveled on subsequent flights with confirmed cases. Notably, the ship reached the Canary Islands on May 10, where disembarkation took place, and most crew members and passengers were repatriated.

Hantavirus cardiopulmonary syndrome (HCPS), commonly referred to as hantavirus pulmonary syndrome (HPS), is a viral respiratory disease caused by hantaviruses in the Orthohantavirus genus, part of the Hantaviridae family. Over 20 viral species have been recognized within this genus. Hantaviruses are associated with two primary clinical syndromes in humans: HPS, which is mainly reported in the Americas, and hemorrhagic fever with renal syndrome (HFRS), more frequent in Europe and Asia. Notably, human-to-human transmission has only been documented for HPS related to Andes virus infections. Andes virus is endemic in South America, with confirmed cases primarily from Argentina and Chile, with additional strains reported in Uruguay and Brazil.

Hantavirus infection in humans typically occurs through contact with infected rodent urine, feces, or saliva, or through contaminated surfaces. This often happens during activities like cleaning in areas with rodent infestations, but it can also occur during normal activities in highly infested places. Most cases are seen in rural environments, such as farms or fields, where people have greater exposure to such rodents.

HPS symptoms can begin 1-6 weeks after exposure, generally presenting as headaches, fever, dizziness, and gastrointestinal issues before leading to respiratory distress. Symptoms might appear as soon as a week or as late as eight weeks.

Cases of hantavirus globally are relatively infrequent. In 2025, eight countries in the Americas reported HPS with a total of 229 cases and 59 deaths, yielding a case fatality ratio (CFR) of 25.7%. HPS is, however, absent in other global regions. Europe reported 1885 hantavirus infections causing HFRS in 2023, which is the lowest rate since 2019. In East Asia, particularly China and South Korea, HFRS sees thousands of cases per year, although the incidence has declined over recent decades.

The overall CFR for HPS can be quite high, sometimes reaching 50%. There are no approved treatments or vaccines for hantavirus infections. However, early supportive care and transfer to intensive care facilities can improve survival.

Environmental factors affecting rodent populations can influence disease trends. Since hantavirus reservoirs are wild rodents, transmission happens when people come into contact with their habitats. Although limited, human-to-human transmission of HPS from Andes virus has been reported, especially in close-contact community settings. Secondary infections among healthcare workers, while rare, have occurred previously. Transmission is most feasible during the early stages of the illness when the virus is more contagious. Currently, there is little data regarding outbreaks related to human transmission of hantavirus.

Authorities from involved nations, WHO, and partners are coordinating a response, featuring the following measures:

• Continuous communication between WHO and the NFPs of affected nations to ensure effective information sharing.
• International contact tracing is in progress.
• WHO is requesting regular updates on health statuses of high-risk contacts from States Parties through IHR channels.
• Crew members aboard the MV Hondius are advised to maintain physical distancing and remain in cabins when possible.
• Experts from WHO and the European Centre for Disease Prevention and Control (ECDC) have boarded the ship to assist with public health recommendations prior to disembarkation.
• Two Dutch medical professionals have been deployed to monitor health on board. One disembarked in Tenerife, while a nurse came on board for assistance.
• On May 9, WHO Director-General Dr. Tedros visited the Canary Islands to meet with national authorities and support operational coordination.
• Epidemiological investigations continue to clarify links between cases and potential exposure sources.
• WHO has developed specific technical guidance to support the ongoing events.

WHO currently views the public health risk for those aboard the ship as moderate, while assessing the global risk as low for several reasons:

• The Andes virus has shown limited human-to-human transmission in past outbreaks, typically among those who had close, prolonged contact. Effective containment can be achieved through early detection, isolation, and monitoring. However, close quarters on the ship heightened transmission risks.
• HPS associated with hantaviruses can have a high CFR, especially among the elderly and those with preexisting conditions. The average passenger age was 65 years.
• Ongoing investigations into the travel history and possible exposures of the initial cases suggest possible contact with rodents during activities. Current viral sequencing indicates the outbreak likely resulted from a single spillover or closely related events.
• Additional cases might appear among those exposed before containment measures started. Still, the current response—quarantining individuals who left the ship and quickly isolating new suspect cases—is expected to limit further spread.
• Without a specific antiviral treatment for HPS, prompt transfer to well-equipped emergency facilities is important for positive outcomes. This can be challenging, especially in remote regions.

For the broader public not directly exposed, the likelihood of infection remains low. Transmission mainly occurs with close contact, and proactive measures like early detection and isolation can effectively mitigate the risk.

WHO advises involved States Parties to maintain public health coordination and management related to the cruise ship and any relevant flights. This should include contact tracing, monitoring, managing suspected cases, testing, and ensuring clear communication with the public. High-risk contacts, including household members or healthcare workers with unprotected exposure, should be actively monitored for 42 days after their last exposure.

While maintaining awareness of potential pre-symptomatic transmission, routine lab testing for low-risk contacts isn’t recommended, although they should monitor themselves and seek medical help if symptoms arise. Investigations into contacts should consider passenger lists and other available data to ensure thorough tracking.

Prompt isolation and adherence to preventative protocols are crucial to safeguard healthcare workers, other passengers, and crew members.

• Standard precautions should be applied at all times, including hand hygiene and proper waste management.
• Suspected or confirmed cases should be isolated in well-ventilated rooms with their doors closed.
• Healthcare workers must use personal protective equipment appropriately.

For suspected cases, quick transfer to emergency departments is crucial. Initial management should focus on supportive care, with cautious fluid management and oxygen support as necessary. Although ribavirin has shown effectiveness against HFRS, it hasn’t been validated for HPS, and no specific antiviral treatments are currently approved.

Public health messaging should emphasize early detection and reducing exposure risks, especially for at-risk activities. Risk communication strategies should be clear, timely, and culturally appropriate to raise awareness about hantavirus transmission.

At present, WHO does not recommend altering routine activities for the general public beyond monitoring specific high-risk contacts. Travel or trade restrictions are not required beyond managing identified high-risk contacts.

• World Health Organization. Management of contacts of Andes virus (ANDV) cases from the MV Hondius cruise ship.
• World Health Organization. WHO Technical note for the disembarkation and onward management of passengers and crew in the context of an Andes virus-associated cluster MV Hondius cruise ship.
• World Health Organization. Hantavirus fact sheet.
• World Health Organization. WHO’s response to hantavirus cases linked to a cruise ship.
• World Health Organization. Handbook for management of public health events on board ships.
• World Health Organization. Guide to Ship Sanitation, 3rd edition.
• Preliminary analysis of Orthohantavirus andesense virus sequences from a cruise-ship related cluster, May 2026.
• World Health Organization. Standard precautions for the prevention and control of infections: aide-memoire.
• World Health Organization. Transmission-based precautions for the prevention and control of infections: aide-memoire.
• World Health Organization. Hantavirus outbreak toolbox.