Mystery Virus Kills Three on Argentina–Cape Verde Voyage

Three people have died following a suspected hantavirus outbreak aboard a cruise ship travelling between Argentina and Cape Verde, raising urgent questions among global health authorities about how the potentially deadly virus spread among passengers.

The World Health Organisation confirmed one case of the virus as of the time of reporting, while stressing that the overall public health risk remains low. However, the deaths and the maritime setting have intensified scrutiny over whether human-to-human transmission — a rare and largely unprecedented phenomenon — may have occurred on the vessel.

The ship departed from Ushuaia in southern Argentina, a region where the Andes virus — one of the deadliest hantavirus strains — is known to circulate. Health authorities now suspect the Andes strain may be responsible, pending viral sequencing results that would confirm which specific strain is involved.

Virginie Sauvage, head of France’s National Reference Centre for Hantaviruses, stated publicly that identifying the precise strain would be critical to understanding what occurred onboard.

Hantaviruses are broadly classified into two groups: old world strains, found across Europe, Asia, and Africa, with mortality rates reaching up to 14 percent; and new world strains, indigenous to the Americas, which can kill more than 40 percent of those infected. New world strains are particularly aggressive, rapidly attacking the lungs and sometimes the heart.

There is no specific treatment for hantavirus. Medical intervention focuses on managing symptoms, with severe cases requiring oxygen therapy in intensive care. Early treatment significantly improves survival outcomes.

Under normal circumstances, the virus does not pass between humans. Infection occurs primarily through inhaling aerosols contaminated by rodent saliva, droppings, or urine — or through direct contact with infected animals. The Andes virus remains the only known strain with confirmed cases of human-to-human transmission, though even those cases required prolonged close contact.

Investigators are currently examining two possible explanations for the cruise ship cluster: direct transmission between passengers onboard, or separate infections contracted before boarding — possibly during a shared excursion in Argentina.

If new world hantavirus transmission between humans has occurred on the ship, health authorities have described it as potentially unprecedented.

Countries including China, Russia, South Korea, Finland, and France collectively report several thousand hantavirus cases annually, with infections occurring year-round globally. High-risk individuals include forestry and farm workers, the elderly, immunocompromised persons, and those with existing health conditions.