A hantavirus outbreak aboard a cruise ship crossing the Atlantic has killed three people and left five others under suspicion of infection, with health authorities expanding contact tracing across continents after one of the deceased attempted to board a Europe-bound flight shortly before her death.
According to AP and other reports on Tuesday (local time), the hantavirus infections on the Dutch-flagged cruise ship MV Hondius totaled eight cases, comprising three confirmed and five suspected. The vessel departed the port of Ushuaia, Argentina, on May 1.
The first symptomatic case emerged on the sixth day of the voyage, May 6. A 70-year-old Dutch man complained of fever, headache and mild diarrhea, and died five days later after suffering respiratory failure. His 69-year-old wife, who disembarked with her husband's body at the British territory of Saint Helena on April 24 and traveled to Johannesburg, South Africa, also deteriorated rapidly and died on April 26. She tested positive for hantavirus posthumously.
Patients continued to emerge thereafter. On April 27, a British passenger fell ill and was airlifted to South Africa, and on May 2, a German woman died on board. After the cruise ship anchored near Cabo Verde in West Africa on May 3, three additional suspected patients from the U.K., Germany and the Netherlands were disembarked on May 6 for transfer to Europe.
The incubation period for hantavirus ranges from one to eight weeks. This makes it difficult to determine whether passengers boarded already infected or were exposed during the voyage. However, Argentine epidemiological authorities are focusing on the possibility that the deceased Dutch couple was infected during a bird-watching tour they participated in at Ushuaia before departure, AP reported. The explanation is that the tour itinerary included a visit to a landfill, where they may have come into contact with rodents.
The World Health Organization (WHO) offered a similar view. Anaïs Legand, a WHO expert on viral hemorrhagic fevers, said, "The incubation period is usually two to three weeks, and the first patient likely was not infected inside the ship or at one of the islands where it made port," adding, "He clearly had rodent-related exposure before boarding."
Warning signs in Argentina are also growing stronger. According to the Argentine Ministry of Health, there have been 101 hantavirus infections since June of last year, roughly double the figure for the same period the previous year. On May 5, an additional infection case was reported in Bariloche, the northern gateway to Patagonia.
The decisive factor that kept the incident from being confined to a single ship was the travel route of the second fatality. According to AFP, the Dutch woman took a South African airline Airlink flight from Saint Helena to Johannesburg. The same flight carried 82 passengers and six crew members, whom authorities are now tracing.
The trail did not end there. Dutch airline KLM said the woman initially boarded one of its flights from Johannesburg to Amsterdam on April 25 but disembarked before takeoff. KLM said, "Due to this passenger's medical condition, the crew decided not to allow her to remain on board, and the flight departed for the Netherlands after she disembarked."
Passengers who ended their travel early at ports of call are also a variable. A Swiss passenger who returned home in late April developed symptoms after arrival and was hospitalized in Zurich, where he was confirmed to be infected with the "Andes variant," which is capable of human-to-human transmission. His accompanying wife remains asymptomatic. Swiss authorities are tracing close contacts but maintain there is no immediate risk to the general public. British authorities have also identified two returning nationals and recommended self-isolation.
The WHO believes the possibility that this outbreak will lead to widespread transmission on the scale of the COVID-19 pandemic is low. Human-to-human transmission of hantavirus is very rare and requires close contact. However, it is a fatal disease for individual patients. According to the U.S. Centers for Disease Control and Prevention (CDC), about 38% of patients who develop respiratory symptoms may die.
Early symptoms resemble the flu, with fatigue, fever, chills and muscle pain, but over time the heart, lungs and kidneys are damaged, progressing to respiratory failure and organ failure. There is no specific treatment, and symptom management is effectively the only response available.
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