What We Know About the Cruise Ship Hantavirus Outbreak

Three passengers have died and at least eight people have fallen ill following a hantavirus outbreak aboard the MV Hondius, a Dutch cruise ship that departed Ushuaia, Argentina, on April 1. The World Health Organization says the overall public health risk remains low, but the outbreak has prompted medical evacuations, international contact tracing, and renewed attention to a virus most people have never heard of.

The WHO first received reports of a cluster of severe acute respiratory illness aboard the ship on May 2. Since then, the situation has evolved rapidly. The first fatal case was a 70-year-old Dutch man who developed fever, diarrhea, and headache on April 6 and died five days later from respiratory distress. His 69-year-old wife, who left the ship at Saint Helena on April 24, died in a Johannesburg hospital on April 26 after her condition deteriorated during a commercial flight. PCR testing later confirmed hantavirus in her case. A third fatality, a German woman, died on May 2 after presenting symptoms on April 28.

A fourth confirmed case — an adult man currently hospitalized in South Africa after being medically evacuated from the ship — has also tested positive for hantavirus. Switzerland identified a fifth case from a passenger who arrived at a hospital in Zurich. On Wednesday, the WHO confirmed three additional individuals with suspected hantavirus were medically evacuated to the Netherlands.

Understanding what hantavirus is — and what it is not — is critical right now. Hantaviruses are a family of viruses carried primarily by rodents. Humans typically contract the virus by inhaling particles from dried rodent saliva, urine, or droppings. The strain linked to this outbreak appears to be the Andes virus, which is common in South America and is notable for being one of the few hantavirus strains known to transmit between humans through close contact in enclosed spaces.

Person-to-person transmission of hantavirus is rare, but the Andes strain makes it possible. That distinction matters. The long incubation period — symptoms can appear up to eight weeks after exposure — means additional cases could still emerge among passengers who left the ship at earlier ports of call.

For the Americas, hantavirus infection can cause hantavirus pulmonary syndrome, or HPS, which starts with fever, fatigue, and muscle aches before progressing to shortness of breath and fluid in the lungs. HPS carries a fatality rate of 12 to 45 percent depending on the strain. There is no cure and no widely available vaccine. Surviving severe illness requires prompt ICU-level care.

As of Wednesday, the MV Hondius has departed Cape Verde and is en route to Spain's Canary Islands, a journey of three to four days. The 145 remaining people aboard are currently asymptomatic but are wearing masks and practicing social distancing. Three additional medical personnel have boarded the ship to provide care during the crossing.

The WHO has been emphatic that this is not a COVID-like threat. Director-General Tedros Adhanom Ghebreyesus stated Wednesday that "at this stage, the overall public health risk remains low." Maria Van Kerkhove, a top WHO epidemiologist, put it plainly: "This is not the next COVID, but it is a serious infectious disease. Most people will never be exposed to this."

Stanford infectious disease expert Dr. Abraar Karan noted that while the outbreak likely will not resemble COVID, the cruise ship setting creates complications. Passengers who disembarked before the outbreak was detected could have exposed others through close contact, making thorough contact tracing essential. The two British citizens who left the ship early and returned to the UK are now self-isolating along with their close contacts.

What This Means For You: The hantavirus outbreak on the MV Hondius is a serious situation for those directly affected, but it does not pose a broad public health threat. If you are planning a cruise, this is not a reason to cancel — hantavirus is extremely rare, and the Andes strain's person-to-person transmission requires close, prolonged contact in enclosed spaces. However, if you or someone you know was aboard the MV Hondius during its April-May voyage, monitor for symptoms (fever, fatigue, muscle aches, shortness of breath) for up to eight weeks and seek medical attention promptly if any develop. The broader lesson: emerging infectious diseases remain a reality of global travel, and robust contact tracing — not panic — is the right response.