Hantavirus: History and the 2026 Outbreak

From a Korean river to a South Atlantic cruise ship. Updated May 2026.

Origins of the Name

Hantavirus takes its name from the Hantan River in South Korea, where in 1976 virologist Ho Wang Lee and colleagues first isolated the pathogen responsible for Korean Hemorrhagic Fever. The disease had been striking soldiers and civilians in the region for decades, with a particularly notable cluster during the Korean War in the early 1950s when thousands of United Nations troops fell ill with severe kidney failure and hemorrhagic symptoms. The cause had remained a mystery for more than twenty years. Lee's isolation of what became known as Hantaan virus marked the founding moment of modern hantavirus science.

Subsequent research revealed that hantaviruses were far more widespread than the Korean peninsula alone. Related viruses were found across Asia and Europe, all sharing the same basic biology: carried by rodents, shed in their urine and droppings, and capable of infecting humans who came into contact with contaminated material.

Discovery in the Americas

In May 1993, a young Navajo athlete in the Four Corners region of the southwestern United States died of acute respiratory failure within days of his fiancee, who had died of the same cause shortly before. Health authorities in New Mexico began investigating what appeared to be a cluster of sudden, unexplained deaths among previously healthy young adults. Over the following weeks, the CDC, working with Navajo Nation health officials and state laboratories, identified a previously unknown hantavirus as the cause. The strain was eventually named Sin Nombre virus, and the disease it produced, Hantavirus Pulmonary Syndrome (HPS), was formally described for the first time.

The Four Corners outbreak was eventually traced to a population explosion among deer mice driven by unusually heavy rains and an abundance of pinon nuts. It killed more than half of those infected and demonstrated that hantaviruses were capable of causing a devastating new respiratory illness entirely distinct from the kidney disease seen in Asia. The discovery fundamentally changed how public health officials thought about emerging infectious diseases in North America.

The Andes Virus and South America

In 1995, researchers in Argentina and Chile documented another new hantavirus strain circulating in the Andes mountain region. This strain, named the Andes virus, shared the capacity to cause HPS but carried one additional and alarming property: it was the only hantavirus ever found capable of spreading directly between humans. Person-to-person transmission, documented in clusters of cases among close household contacts and healthcare workers, set the Andes virus apart from every other known strain in the family.

The Andes virus is carried primarily by the long-tailed pygmy rice rat, found throughout Patagonia in Argentina and Chile. Endemic transmission continues in these countries every year, particularly in rural and forested regions. Argentina and Chile together account for the majority of the world's documented HPS cases. Until 2026, every recorded outbreak had remained geographically contained to South America.

The MV Hondius Outbreak (2026)

The MV Hondius is a Dutch expedition cruise ship operated by Oceanwide Expeditions. On 1 April 2026 it departed Ushuaia, Argentina, carrying more than 150 passengers and crew from 23 nationalities on an Antarctic and South Atlantic voyage. The itinerary took the ship through some of the most remote waters on earth: mainland Antarctica, South Georgia, Nightingale Island, Tristan da Cunha, Saint Helena, and Ascension Island.

The first passenger to fall seriously ill deteriorated during a flight from Saint Helena to Johannesburg, South Africa on 25 April and died on arrival at hospital. Laboratory testing subsequently confirmed Andes hantavirus infection. A second death followed: a Dutch couple who had been among the ship's passengers. A third fatality, a German national, was confirmed in early May. By 8 May 2026, the World Health Organization had reported six confirmed cases and two additional probable cases across multiple countries, representing the largest documented multi-country hantavirus cluster in history.

As the scale of the outbreak became clear, the ship was diverted to Tenerife in Spain's Canary Islands. Spanish authorities coordinated the evacuation and repatriation of the remaining passengers and crew, and the WHO Director-General traveled personally to Tenerife to oversee the response. Governments across four continents activated contact tracing for passengers who had disembarked at earlier ports before the outbreak was identified.

Why This Outbreak Is Scientifically Significant

The Hondius outbreak is the first documented hantavirus event linked to cruise ship travel, raising new questions about how Andes virus transmits in enclosed passenger environments and what the effective infectious dose might be. The ship's route through remote southern Atlantic islands meant that passengers from dozens of countries were potentially exposed before any alert was issued, creating a complex, genuinely global contact tracing challenge.

Researchers from the WHO, ECDC, and CDC are actively investigating the outbreak's chain of transmission. The results of this investigation are expected to reshape understanding of Andes virus human-to-human spread and inform future guidance for travel medicine, cruise ship biosafety, and expedition tourism to endemic regions.

A Brief Timeline