Can Hantavirus Spread from Human to Human - Here's Everything You Need to Know About the Virus

On 2 May 2026, the World Health Organization received notification from the United Kingdom about a cluster of severe acute respiratory illness aboard a Dutch-flagged cruise ship. As of 4 May 2026, seven cases had been identified, including three deaths, one critically ill patient, and three individuals with mild symptoms.

WHO confirmed the outbreak is caused by the Andes strain of hantavirus, found in South America and primarily carried by a species of rodent called the pygmy rice rat.

Maria Van Kerkhove, an American epidemiologist and technical adviser to the WHO, said at a briefing: "Our assumption is they were infected off the boat and then joined the cruise. However, we do believe that there may be some human-to-human transmission happening among really close contacts, the husband and wife, people who've shared cabins."

Can Hantavirus Spread From Human to Human?

The short answer is: most strains cannot. But there is one important, deadly exception.

The Andes virus is the only type of hantavirus known to spread from person to person, and this spread is usually limited to people who have close contact with the ill person.

Most hantaviruses are not spread between humans. It is unclear why, although in one laboratory study, the viruses appeared to produce very few mature virus particles in the lungs of infected humans.

So why can the Andes strain do what the others cannot? One line of research suggests Andes virus may be uniquely resistant to the antiviral components of human saliva that seem to neutralize other strains before they can spread.

That resistance makes it dangerous. But it still has real limits.

How Does the Andes Virus Actually Spread Between People?

This is where the science gets both reassuring and sobering. The Andes virus does not spread like the flu or COVID-19. It requires something far more intimate.

"Andes virus, as a hantavirus, requires a significant degree of contact with bodily fluids," said Sabra Klein, professor at the Johns Hopkins Bloomberg School of Public Health. "In the original reports that came out in the early 2000s, case studies show spread between married couples, people who live together and are intimate. That is where you have the spread."

Unlike measles and Covid, which can be spread by viruses lingering in the air after an infected person has left a room, Andes virus is spread by close contact, according to immunologist and hantavirus researcher Steven Bradfute at the University of New Mexico Health Sciences Center.

When human-to-human transmission of Andes virus does occur, it is associated with close and prolonged contact, particularly among household members or intimate partners, and appears most likely during the early phase of illness, when the virus is more transmissible.

The Superspreader Lessons From Argentina

One of the clearest windows into how Andes virus spreads between people comes from a devastating 2018 outbreak in a small Argentine village.

In 2018, health authorities in southern Argentina scrambled to understand why nearly three dozen people in the tiny village of Epuyen had fallen gravely ill. By the end of the outbreak, 11 of them had died. Their illness caused many to be admitted to intensive care for pneumonia and severe breathing problems.

A birthday party in late 2018 kicked off the outbreak, which involved three separate superspreader events where a single person passed the infection to several others.

Investigators learned something critical about timing. The window for transmission of the Andes virus appears to be short, about a day. People are at their peak of infectiousness on the day they develop a fever. But within that window, the virus spreads relatively easily even during brief proximity.

In recorded history, there have been fewer than approximately 300 cases of human-to-human transmission of Andes virus out of about 3,000 total Andes cases overall, according to researchers advising on the current cruise ship outbreak.

In recorded history, there have been fewer than approximately 300 cases of human-to-human transmission of Andes virus out of about 3,000 total Andes cases overall, according to researchers advising on the current cruise ship outbreak.

Those numbers put the risk into perspective. But they do not make it any less serious for those affected.

How Most People Actually Get Hantavirus

The vast majority of hantavirus infections worldwide have nothing to do with human-to-human contact.

Transmission of hantaviruses to humans occurs from contact with contaminated urine, droppings, or saliva of infected rodents. Infection may also occur, though less commonly, through rodent bites. Activities that increase exposure risk include cleaning enclosed or poorly ventilated spaces, farming, forestry work, and sleeping in rodent-infested dwellings.

When hantaviruses make the jump from animals into humans, it often happens in situations when contaminated urine, droppings, or nesting materials of an infected rodent get stirred up, for example, when someone is sweeping out a barn. People can also get infected when saliva, urine, or feces from an infected rodent gets into skin wounds or into a person's eyes, nose, or mouth.

A widely reported hantavirus case in early 2025, involving the death of Betsy Arakawa, wife of actor Gene Hackman, at her home in Santa Fe, highlighted that exposure can occur even in everyday settings when infected rodents are present.

The takeaway is clear: you do not need to be on a polar expedition cruise to be at risk. A mouse in your garage can carry the same lethal cargo.

How Deadly Is Hantavirus? The Numbers Are Stark

This is not a virus to take lightly. The fatality rates are among the highest of any known infectious disease.

Hantavirus infections are relatively uncommon globally but are associated with a case fatality rate of under 1 to 15 percent in Asia and Europe and up to 50 percent in the Americas.

The Andes virus causes a severe lung-focused form of disease, and the fatality rate is estimated between 35 to 50 percent.

In 2025, across the Americas, eight countries reported 229 cases and 59 deaths, representing a case fatality rate of 25.7 percent.

Between 10,000 and 100,000 hantavirus infections are thought to occur each year globally, most in Asia and Europe. In the Americas, only 150 to 300 infections are reported annually, with Argentina, Brazil, Chile, and Bolivia typically accounting for the majority.

These numbers explain why health authorities treat every confirmed case as a serious event.

What Are the Symptoms and When Do They Appear?

Hantavirus is a master of disguise, at least in its early stages.

Hantavirus pulmonary syndrome is characterized by headache, dizziness, chills, fever, muscle pain, and gastrointestinal problems including nausea, vomiting, diarrhea, and abdominal pain, followed by sudden onset of respiratory distress and low blood pressure.

Symptoms typically occur two to four weeks after initial exposure to the virus. However, symptoms may appear as early as one week and as late as eight weeks following exposure.

Diagnosing hantavirus in a person infected less than 72 hours is difficult. Early symptoms such as fever, headache, muscle aches, nausea, and fatigue are easily confused with influenza.

That similarity to flu makes early detection exceptionally challenging. If you have been in a rodent-heavy environment and develop these symptoms, the CDC advises seeing a physician immediately and mentioning potential rodent exposure.

What Is the Global Risk Right Now?

Despite the alarming headlines from the cruise ship, global health authorities are urging measured concern rather than panic.

WHO currently assesses the risk to the global population from the MV Hondius event as low and will continue to monitor the epidemiological situation.

"The majority of hantaviruses cannot be spread through human-to-human spread," Johns Hopkins professor Sabra Klein said. "This happens to be the only one. It is still unbelievably rare."

While WHO says the threat posed by the current cruise ship outbreak is low, it has classified hantaviruses as emerging priority pathogens with high potential to spark international public health emergencies because of how serious these infections can be. Hantavirus infection can be lethal in up to 40 percent of cases.

The WHO's "priority pathogen" classification is a signal that scientists are watching this virus closely. The cruise ship outbreak, rare as it is, serves as a reminder that under the right conditions, even a tightly controlled pathogen can find unexpected pathways.

How to Protect Yourself: Practical Prevention

The good news is that hantavirus prevention is largely within your control.

Eliminating or minimizing contact with rodents in your home, workplace, or campsite is the primary way to reduce exposure. Seal holes and gaps in your home or garage to keep rodents from entering. Place traps in and around your home to decrease rodent infestation. Clean up any easy-to-get food that might attract rodents.

During outbreaks or when cases are suspected, early identification and isolation of cases, monitoring of close contacts, and application of standard infection prevention measures are important to limit further spread. Available evidence indicates the risk of healthcare-associated transmission of hantavirus, including Andes virus, is very low when appropriate infection prevention and control measures are applied.

For healthcare workers and anyone in close contact with a suspected Andes virus patient, standard precautions combined with transmission-based precautions during provision of care are advised.

The Bottom Line

Hantavirus is rare, but it is real, and in the case of the Andes strain, it can move from person to person under the right conditions. The ongoing cruise ship outbreak offers scientists a live opportunity to deepen their understanding of exactly how that transmission works.

Because person-to-person transmission is unusual for hantaviruses, understanding this pathway is critically important for identifying cases early and limiting the spread of infection.

For now, global health authorities agree: the worldwide risk remains low. But vigilance, especially around rodent contact, remains the smartest and most effective defense anyone has against this lethal and largely misunderstood virus.