It wouldn't be the bug I'd pick as the next pandemic
Aboard the Dutch cruise ship MV Hondius, a rare and lethal respiratory illness has claimed three lives and left others gravely ill — a reminder that nature's most dangerous pathogens are not always its most ambitious. The Andes strain of hantavirus, first encountered in dying Navajo communities in 1993, carries a fatality rate that commands respect, yet its very stability and narrow transmission window make it an unlikely architect of pandemic. A Newcastle expert who helped discover the virus three decades ago offers measured reassurance: the bugs most likely to reshape the world are the restless, mutating ones — and hantavirus, for all its ferocity, is not among them.
- Three passengers are dead and others critically ill aboard a confined cruise ship, where close quarters turned a rare virus into a shared threat.
- The Andes strain's ability to pass between humans — unique among hantaviruses — has triggered WHO monitoring and international alarm.
- Health authorities are racing against the virus's two-to-three-week incubation window, knowing additional cases may still be incubating among those who sailed.
- Isolation rather than mass intervention is the containment strategy: the virus demands proximity to spread, so distance becomes the medicine.
- A leading expert is urging calm, pointing out that hantavirus has barely mutated in thirty years while COVID and influenza reinvent themselves constantly.
On May 2, the World Health Organisation learned that passengers aboard the MV Hondius, a Dutch cruise ship, were falling gravely ill. By May 7, eight cases had been confirmed or suspected, three of them fatal — a Dutch couple and a German citizen among the dead, with a UK passenger evacuated to intensive care in South Africa. The cause was the Andes strain of hantavirus, a pathogen that floods the lungs with fluid and kills between 20 and 50 per cent of those who develop severe respiratory illness.
Dr Craig Dalton, a communicable disease specialist at the University of Newcastle, was part of the team that first identified this strain in 1993, when young Navajo people in the United States were dying with terrifying speed — fever and muscle aches giving way to catastrophic lung failure within hours. What set the Andes variant apart then, and what matters now, is its rare capacity for human-to-human transmission. Every other hantavirus strain requires contact with infected rodent droppings or saliva. The Andes strain broke that rule, though its reach remains narrow: it spreads only through prolonged, close face-to-face contact — exactly the kind of proximity a cruise ship's cabins and dining rooms provide.
Dalton is not alarmed about a global outbreak. The virus is remarkably stable, having undergone only one significant mutation in over thirty years. Compared to COVID-19 or influenza, which mutate readily and travel far, hantavirus is epidemiologically constrained. "You probably should be more concerned about someone sitting in a general practice office in Newcastle with COVID or influenza," he said. The WHO has warned that further cases may emerge given the incubation period, but containment here is straightforward in principle: isolate the infected, keep faces apart. Australia has never recorded a confirmed human case — a fact Dalton attributes to either mild undetected infections or genuine absence. The virus remains, for now, a contained tragedy rather than a gathering storm.
On May 2, the World Health Organisation received word that passengers aboard the MV Hondius, a Dutch-registered cruise ship, were falling seriously ill with respiratory symptoms. By May 7, eight cases had been documented, three of them fatal. The culprit was the Andes strain of hantavirus—a virus so aggressive it floods the lungs with fluid, yet so contained in its spread that a Newcastle disease expert who helped identify it three decades ago is not losing sleep over a global outbreak.
Dr Craig Dalton, a communicable disease specialist at the University of Newcastle, was part of the research team that first encountered this particular strain in 1993. Young Navajo people in the United States were dying suddenly, their illness arriving with shocking speed: fever, muscle aches, then a catastrophic failure of the lungs. Dalton watched fit, healthy people collapse and die within hours. The virus attacked the pulmonary system, causing blood vessels to leak. It was a new kind of hantavirus entirely—the only strain known at the time attacked the kidneys instead.
What made the Andes strain different, and what makes it present on that cruise ship now, is its rare ability to pass from one human to another. All other hantavirus strains require contact with infected rodent urine, faeces, or saliva. The Andes variant, found in South America, broke that rule. Yet even this capacity for human transmission is fragile and narrow. Dalton emphasises the virus is not particularly infectious. It spreads only through prolonged, close face-to-face contact—the kind of proximity that a cruise ship, with its confined cabins and shared dining spaces, unfortunately provides. A person sitting directly beside an infected passenger, or in front of them, faces genuine risk. Someone across the room does not.
The fatality rate for hantavirus infections that reach the lungs and present to hospital ranges between 20 and 50 per cent, Dalton notes. But there are likely mild cases that never reach a doctor, never enter the health system at all. The disease typically unfolds over two to three weeks: non-specific fever and muscle aches first, then coughing, before severe respiratory syndrome takes hold.
When asked whether hantavirus might become the next pandemic, Dalton's answer was direct. "It wouldn't be the bug that I would be picking," he said. The virus is remarkably stable. In more than thirty years, it has undergone only one significant mutation—the leap from animal-to-human transmission to human-to-human transmission. Compare that to COVID-19 or influenza, both of which mutate readily and spread with ease. "You probably should be more concerned about someone sitting in a general practice office in Newcastle with COVID or influenza," Dalton said, "because those viruses are more likely to mutate."
The three deaths documented so far—a Dutch couple and a German citizen—represent a tragedy for those families and a warning about the virus's lethality. A UK passenger was removed from the ship and placed in intensive care in South Africa. The WHO director-general acknowledged on May 7 that given the virus's incubation period, more cases could yet emerge. But containment, in this instance, is not a matter of global coordination or vaccine rollout. It is a matter of isolation, of keeping infected people away from the faces of others. Australia has never recorded a confirmed human case of hantavirus, a fact attributed either to lack of diagnosis or to infections mild enough to escape notice. The virus, for all its danger, remains geographically and epidemiologically confined.
Notable Quotes
In terms of risk, you probably should be more concerned about someone sitting in a general practice office in Newcastle with COVID or influenza because those viruses are more likely to mutate.— Dr Craig Dalton, University of Newcastle communicable disease expert
This is a very stable virus. There's only been one mutation from the non-human to human transmission to the human-to-human transmission type.— Dr Craig Dalton
The Hearth Conversation Another angle on the story
When you say the Andes strain is the only one that spreads human-to-human, what changed? Why this one and not the others?
That's the question we were asking in 1993. We think it has to do with the virus's ability to replicate in the respiratory tract and be shed in respiratory droplets. The other strains stay in the kidneys, in the urine. Different anatomy, different transmission route.
So the cruise ship is almost a perfect storm for this virus—confined air, people breathing on each other for days.
Exactly. Dalton worked on cruise ships as a doctor. He knows the environment. The virus doesn't need a crowd. It needs proximity. One infected person in a cabin with someone else, or at a dinner table, and you've created the conditions it needs.
But he's not worried about a pandemic. Why?
Because the virus doesn't mutate much. It's stable. And it's not that infectious even in ideal conditions. COVID and flu are different animals—they change constantly, they spread through the air in ways hantavirus doesn't. If you're going to worry about a pandemic, those are the ones.
What about the people who died? Does their death rate change the calculation?
No. Twenty to fifty per cent fatality rate is terrifying if you're infected. But if the virus can't spread easily, if it only moves between people in close quarters, then the absolute number of cases stays small. Severity and transmissibility are different things.
So what happens next on that ship?
Isolation. Quarantine. The incubation period is two to three weeks, so more cases might appear. But the virus isn't going to jump off the ship and sweep through Newcastle or Sydney. It's contained by its own nature.