The travelers disembarked the Dutch-flagged expedition vessel MV Hondius during a scheduled stop at Saint Helena, a remote British territory in the South Atlantic, on April 23. They did not know they had been exposed to the virus, which has a fatality rate of up to 40%, a passenger who remains on the ship told the Spanish newspaper El PaÃs.
A Swiss man who flew home with his wife was confirmed positive for hantavirus on Wednesday, Swiss authorities said. He was first admitted to a Zurich hospital and initially tested negative. The virus can stay dormant in the body for up to eight weeks.
The passenger told El PaÃs that the group scattered across the globe. “The Australian went back to Australia, the one from Taiwan to Taiwan, the Americans to all corners of North America. The Englishman to England, the Dutch to their homes,” the passenger said.
The United Kingdom’s Health Security Agency (UKHSA) confirmed that two British nationals who had been on the Hondius returned home and are self-isolating. Neither has shown symptoms. The agency said the risk to the general public remains “very low.”
Australia’s Department of Foreign Affairs and Trade said it was aware Australians were on board but had no information that any had been affected by the outbreak. Sky News Australia reported that one Australian passenger was among the 23 who left the ship at Saint Helena.
The World Health Organization said international contact tracing is underway. Oceanwide Expeditions, the Dutch company that operates the Hondius, emailed former passengers about the outbreak, though the WHO did not say exactly when those messages were sent. A passenger claimed that the WHO did not begin reaching out to those who had left until three days ago, even though the first passenger fell ill on April 6.
The Hondius outbreak has killed three people. A 70-year-old Dutch man died on April 11, his 96-year-old wife died after leaving the ship, and a German passenger died on May 2. Argentine investigators believe the virus was brought on board by a Dutch couple who visited a landfill during a bird-watching excursion in Ushuaia, Argentina, days before the ship departed on March 20. Both that husband and wife are among the dead.
The strain involved is the Andes virus, a rare form of hantavirus that can spread between people through close contact, according to the WHO. Experts say the risk of widespread infection is low because the virus is not as contagious as respiratory illnesses such as COVID-19.
The Hondius, carrying about 149 passengers and crew, was barred from docking in Cape Verde after the outbreak was reported. It is now sailing toward the Canary Islands, where Spanish authorities have expressed reluctance to let it dock. The ship operator says it is still in talks with officials about where and when the vessel can be received.
Health agencies in multiple countries are monitoring returning passengers. U.S. authorities are tracking residents in at least three states who were on the ship and have since come home, according to local news reports.
The UKHSA said it is using Foreign Office, Home Office, and border force resources to trace anyone who may have been in contact with the two British passengers who flew home via Johannesburg.