You may have seen recent news about a hantavirus outbreak linked to the cruise ship MV Hondius. As of 12 May 2026, 11 cases (nine confirmed, two probable) have been reported, including three deaths. Affected passengers are currently hospitalised in Switzerland, France, Germany, Spain and the Netherlands.

Hantavirus is typically contracted through contact with infected rodents, specifically their urine, droppings or saliva. The virus in this outbreak has been identified as Andes hantavirus, the only strain known to be capable of person-to-person transmission. However, this requires close and prolonged contact with an infected individual. Symptoms of this severe respiratory illness can include fever, extreme fatigue, muscle aches, stomach pain, vomiting, diarrhoea and shortness of breath.

For the CERN community, the risk remains low. This outbreak is tied to a specific travel event in a remote region of the South Atlantic Ocean and there is no evidence of wider community spread. The HSE Department and the CERN Medical Service are actively monitoring the situation in both Host States and will publish further communications as necessary depending on the evolution of the situation.

What to do:

• Keep informed about the procedures in both of CERN’s Host States:
  • France: high-risk contacts face a 15-day hospital quarantine (possibly extended to 42 days), including PCR and serological testing.
  • Switzerland: while contact tracing has been initiated for confirmed cases, there are no mandatory quarantine measures in place for the general public or contacts at this time.

• If you believe you may have been exposed, contact the authorities of your country of residence and inform the CERN Medical Service by email (infirmary.service@cern.ch) or telephone (+41 22 76 73802).
• If you have contracted Hantavirus or have been confirmed as a contact case by the authorities, please inform the CERN Medical Service immediately.
• For everyone else, no special precautions are required beyond standard hygiene measures.

For any concerns or questions, please contact the CERN Medical Service.