USHUAIA — An Andes virus outbreak aboard the MV Hondius resulted in 13 cases among passengers and crew, with three deaths, as of June 18, 2026. Health authorities from the Netherlands and the United Kingdom informed the European Centre for Disease Prevention and Control (ECDC) and the World Health Organization (WHO) on May 2, 2026, about a severe respiratory infection of unknown cause on the vessel.

Initial laboratory tests detected hantavirus, and subsequent analyses identified a member of the Orthohantavirus andesense complex as the causative agent. As of June 18, there was one probable case and 12 laboratory-confirmed cases. The cases included nine males and four females, with a median age of 65 years, yielding a case fatality rate of 23 percent.

Health officials considered zoonotic transmission through exposure to saliva, urine, or feces from virus-carrying rodents as the most probable infection source for the first case before embarkation. Later infections were likely transmitted among passengers and crew within the ship's confined quarters. Genetic testing revealed near-identical viral sequences among five sequenced cases, which closely resembled the Andes virus from a 2018 outbreak in Epuyén, Argentina.

The MV Hondius departed Ushuaia on April 1, 2026, traveling to locations including South Georgia, Cooper Island, Tristan da Cunha, Gough Island, Saint Helena, and Ascension Island, before arriving in Praia on May 3, 2026. Between April 13 and 15, 2026, ten local residents visited the vessel at Tristan da Cunha, with two staying overnight. Six additional individuals boarded the ship at Tristan da Cunha to travel to Saint Helena.

Thirty-two people disembarked at Saint Helena between April 22 and 24, 2026. The body of the first deceased case and the partner of this individual disembarked there. A third person with an infection left the ship to visit Saint Helena and later reembarked. Contact tracing in Saint Helena identified 22 high-risk contacts who were quarantined and 67 low-risk contacts who underwent passive surveillance.

On April 25, 2026, the second case traveled to South Africa and became ill before departing for the Netherlands. On April 27, 2026, the third case went ashore on Ascension Island and was transferred to South Africa for medical care. The seventh case became ill on May 1, 2026, after returning to Switzerland. From May 3 to May 6, 2026, the MV Hondius remained near Praia, where the fifth and sixth cases and a person exposed to the fourth case were transferred for medical care.

On May 6, 2026, two physicians and two specialists from the ECDC and WHO boarded the vessel. On May 9, 2026, the ECDC classified all passengers and crew as high-risk contacts, recommending a six-week quarantine with active follow-up. The WHO and ECDC determined household onward transmission was unlikely after exposure on the cruise. The MV Hondius reached Granadilla, Tenerife, on May 10, 2026, with 147 asymptomatic individuals. Cases 9 through 13 were repatriated within two days of arrival and tested positive after repatriation or during quarantine monitoring.

The remaining crew members and medical personnel arrived in Rotterdam on May 18, 2026. Quarantine was lifted for 61 passengers and crew in the Netherlands after final tests yielded negative results. Health officials identified 188 high-risk contacts linked to confirmed cases across seven countries.