Hantavirus-associated cluster of illness on a cruise ship: ECDC assessment and recommendations

ECDC was notified on 2 May 2026 by the Netherlands via the European Union (EU) Early Warning and Response System (EWRS) about a cluster of unknown disease with severe respiratory symptoms on a cruise ship in the South Atlantic, operating under a Dutch flag. There were 149 people on board from 23 different nationalities, including nine EU/EEA Member States: Belgium, France, Germany, Greece, Ireland, the Netherlands, Poland, Portugal, and Spain. At the time, two people had died and one had been medically evacuated to South Africa, where the person remained critically ill. A PCR test result for a sample taken from this person came back positive for hantavirus on 3 May 2026.

As of 6 May, a total of seven people had presented with symptoms that included fever, respiratory symptoms, and gastrointestinal symptoms, with at least four rapidly progressing to pneumonia, acute respiratory distress and shock. Of these seven people, three died, one was medically evacuated to South Africa and admitted to an intensive care unit (ICU), two remained symptomatic on board, requiring medical assistance, and one was diagnosed after disembarking the ship and returning to Switzerland. In total, samples from two patients tested positive for hantavirus by PCR; a sample from one additional patient tested positive for Andes virus (ANDV) by PCR. Further laboratory investigations are ongoing.

Orthohantavirus infections are viral zoonotic diseases transmitted to humans primarily through the inhalation of aerosols contaminated with the urine, faeces or saliva of infected rodents. Human disease can be caused by several orthohantavirus species, including the Andes (ANDV) and Sin Nombre (SNV) viruses in the Americas and Puumala and Dobrava viruses in Europe. The incubation time is usually around two weeks but ranges from seven days up to six weeks. Clinical manifestation of hantavirus infection is divided in two clinical syndromes: Hantavirus Pulmonary Syndrome (HPS), seen in the Americas; and Haemorrhagic Fever with Renal Syndrome (HFRS) seen in Europe and Asia. Severe cases can rapidly deteriorate and become life-threatening. ANDV is a hantavirus primarily found in South America that causes HPS with a high fatality rate. Human-to-human transmission is rare but has been documented in the case of ANDV. No effective antiviral treatment is available; supportive care is key for a better chance of survival.

ECDC provides this risk assessment for discussion at the level of the Health Security Committee including the involved countries, UK HSA and the WHO.

Risk assessment

Person-to-person transmission of ANDV has only been documented following close and prolonged contact. The current hypothesis is that some passengers were exposed to ANDV while spending time in Argentina before embarking, where ANDV is endemic, and may subsequently have transmitted the virus to other passengers onboard the cruise ship. At this early stage of the investigation with limited available information, we consider everyone on the ship to be close contacts, due to the closed setting and shared social areas and activities, aligned with the precautionary principle.

Measures are already implemented on board to reduce the likelihood of infection for passengers and crew on the cruise ship. The cruise ship company and the relevant port authorities have also been advised on how to prepare for the management of cases and contacts (e.g. isolation of cases, use of appropriate personal protective equipment, testing, etc).

Even if transmission of ANDV were to happen from passengers evacuated from the ship, ANDV does not transmit easily so it is unlikely that it would cause many cases or a widespread outbreak in the community, if infection prevention and control measures are applied.

In addition, the natural reservoir for ANDV is not present in Europe, so introduction to the rodent population and potential rodent-to-human transmission in Europe is not expected.

The risk to the general population in the EU/EEA from ANDV spreading from this cruise ship outbreak is very low.

Recommendations

• Symptomatic people should be managed proactively and medically evacuated as soon as possible.
• Upon disembarking, diagnostic testing should be carried out by serology or PCR in people with symptoms. However, negative test results may not exclude infection and subsequent virus shedding. The EURL-PH-ERZV offers diagnostic services to EU/EEA countries lacking capability to diagnose ANDV infection.
• Passengers and crew should practice usual enhanced precautions (e.g. frequent handwashing, respiratory etiquette, physical distancing) and vigilant symptom monitoring while on the cruise ship.
• Infection Prevention and Control (IPC) guidance for healthcare settings who are caring for symptomatic individuals include standard and droplet precautions, which can be escalated to airborne precautions in the event that aerosol-generating procedures are performed.
• Risk communication should be tailored to the different target groups recognising their different levels of risk, information needs and responsibilities. Communication should clearly state what is known, what is unknown, and what may change as investigations progress with timely updates.
• Disembarking passengers should be provided with clear instructions and recommendations until their diagnosis is confirmed or ruled out.

ECDC actions

• Epidemiological updates.
• Hantavirus infection factsheet published.
• European Union Reference Laboratory (EURL-PH-ERZV) offered assistance to EU/EEA national reference laboratories for the diagnosis of ANDV.
• ECDC is supporting the response operations through the EUHTF remotely and on the cruise ship in coordination with the affected countries.
• Ongoing collaboration with partners and affected countries on common case definitions and protocol for management of cases and contacts.