A recent hantavirus outbreak on an expedition cruise ship in the Atlantic Ocean has made headlines, sparking fears about a possible new global health crisis. But infectious disease experts are clear: while this virus is dangerous, it is not the next pandemic threat.

Health officials confirmed that 18 American passengers have been safely returned to the United States after their cruise was linked to a deadly outbreak of hantavirus. The U.S. State Department arranged an airlift from the Spanish island of Tenerife on May 10. Two of these passengers are currently being treated in specialized biocontainment units “out of an abundance of caution,” according to the Health and Human Services X account. One passenger tested positive for hantavirus, while the other developed mild symptoms.

Of the repatriated Americans, 16 are receiving care at an ASPR Regional Emerging Special Pathogen Treatment Center in Omaha, Nebraska. The other two are being treated at a RESPTC in Atlanta, Georgia. These Americans are part of a larger group of passengers being monitored as international health authorities continue investigating the outbreak aboard the ship.

What Happened on the MV Hondius?

The Dutch-flagged MV Hondius departed from southern Argentina on April 1 with roughly 150 passengers and crew members aboard. It was supposed to be an expedition cruise through the Atlantic Ocean. But just 11 days into the voyage, a 70-year-old man died after developing fever, headaches, and abdominal pain.

After several additional passengers became ill, the World Health Organization (WHO) identified the ship as the site of a hantavirus outbreak. As of May 12, the number of confirmed hantavirus cases linked to the ship rose to 11, according to the WHO. Three deaths have also been confirmed: a Dutch married couple and a German national.

All remaining passengers have now disembarked and are being repatriated to their home countries, according to the latest statement from Oceanwide Expeditions, the ship’s operator.

Why Are People Worried About a Pandemic?

The repatriation effort caused some alarm and fueled fears of another pandemic. However, experts say these concerns are overstated. The main reason for worry is the possibility that hantavirus spread from person to person aboard the Hondius. This is a rare but documented phenomenon for one specific strain of the virus.

“I think we’re actually in very good shape,” said Lina Moses, PhD, an epidemiologist and disease ecologist at Tulane University’s Celia Scott Weatherhead School of Public Health & Tropical Medicine, who specializes in rodent-borne diseases. “It’s not surprising we’re starting to see more suspected cases. That means that the process is working right. They are monitoring people effectively and identifying people as they become ill,” Moses told Healthline.

How Does Hantavirus Normally Spread?

To understand why this outbreak is not a pandemic threat, it helps to know how hantavirus typically works. Most hantaviruses are spread when people come into contact with the urine, droppings, or saliva of infected rodents, particularly mice and rats. The virus can survive in dust and debris. When someone inhales that contaminated dust, they can become infected.

This is very different from viruses like the flu or COVID-19, which spread easily through the air when people cough, sneeze, or even talk. Hantavirus generally requires direct contact with rodent waste.

However, there is one exception. A strain called the Andes virus, which is found in South America, has been linked to cases of human-to-human transmission. It is the only hantavirus known to spread from person to person.

The Leading Theory on the Cruise Ship Outbreak

The leading theory about what happened on the MV Hondius is that someone carrying the Andes virus boarded the ship and then passed it on to other passengers. Experts say that the level of transmission seen on the ship is reasonable given the circumstances. It does not indicate anything unusual or alarming.

“Previously, we’ve seen person-to-person spread with Andes virus in situations such as close household contacts or at a large social gathering. There’s nothing here that is remarkably different from what we’ve seen in the past,” said Steven Bradfute, PhD, an associate professor at the University of New Mexico Health Sciences Center who specializes in hantavirus research.

Researchers have documented this kind of transmission in Argentina before, including “super spreader” events that resulted in numerous infections at once. Cruise ships can be the perfect environment for disease outbreaks, such as norovirus, which have been documented regularly on ships.

“The most plausible explanation is that the passengers of the cruise ship likely became infected before boarding the cruise, then human-to-human transmission occurred among close contacts,” said Robert Glatter, MD, attending physician in the Department of Emergency Medicine at Lenox Hill Hospital in New York City, and assistant professor of Emergency Medicine at Zucker School of Medicine at Hofstra/Northwell. “The confined ship environment with close quarters and shared spaces likely facilitated transmission between passengers in ways that wouldn’t occur in typical community settings,” he told Healthline.

Not All Viruses Are Created Equal

Not all viruses have the same ability to spread. Some can survive for extended periods outside the body. Others die almost immediately. Some viruses spread easily through the air, while others require prolonged close contact with an infected person.

In the case of the Andes virus, experts say it simply does not have the same transmission potential as a virus like the coronavirus, which causes COVID-19.

“We do have the advantage of historical comparison and what we’re seeing is that Andes virus transmission is much less efficient than what we were seeing in the early stages of COVID,” Moses said.

While experts don’t fully understand the exact mechanisms by which the Andes virus spreads from person to person, unlike other hantaviruses, they are confident in their assessment of its relatively low transmissibility.

“When you compare it to what we see with SARS-CoV-2, the common cold, or influenza, it’s not even in the same ballpark. That doesn’t mean we are dismissing it; these are dangerous viruses, but the transmissibility is not in the same ballpark,” Bradfute told Healthline.

What About Asymptomatic Spread?

Another factor that has caused concern is the disease’s incubation period. The time between infection and the onset of symptoms can range from 4 to 42 days. This long incubation period has stoked fears that individuals who are asymptomatic may be able to transmit the virus without even being aware they have it. This was a major issue during the COVID-19 pandemic.

But experts say that is unlikely for the Andes virus.

“The viral load appears highest during the early symptomatic period when patients experience fever and respiratory symptoms. This pattern means that severely ill patients — those most likely to transmit the virus — are also most likely to be hospitalized and isolated, naturally limiting transmission opportunities,” Glatter said.

In simple terms, people are most contagious when they are already feeling sick. By that point, they are likely to seek medical care and be isolated, which stops the virus from spreading further.

What This Means for the General Public

For most people, the risk of catching hantavirus is extremely low. The virus is not circulating widely in communities. It requires close, extended contact with an infected person or direct exposure to rodent waste.

Here are some key takeaways for readers:

• Hantavirus is not a pandemic threat. The Andes virus does not spread easily from person to person. It is not like COVID-19, the flu, or the common cold.
• Person-to-person transmission is rare. It requires prolonged, intimate contact with someone who is already sick, such as living in the same household or caring for an infected patient.
• The cruise ship was a unique environment. Confined spaces with close quarters and shared facilities can make any virus spread more easily. This does not mean the same thing would happen in a typical community setting.
• Most people are not at risk. Unless you are traveling to rural areas in South America where the Andes virus is found, or you are exposed to rodent droppings, your risk is virtually zero.
• If you are concerned about rodent-borne diseases at home, take simple precautions: seal holes and cracks in your home, store food in rodent-proof containers, and clean up any signs of rodent activity with gloves and a mask.

What Experts Say About Travel and Safety

Infectious disease experts are not changing their own travel plans based on this outbreak. They emphasize that the situation is being handled properly by health authorities.

“I’m not changing any of my travel plans,” Bradfute said. “These viruses are dangerous. They’re to be taken seriously. But from what we know of this virus and what we’re seeing so far, there’s nothing here that is concerning for a pandemic at this point.”

Moses added that the increasing number of suspected cases is actually a good sign. It shows that monitoring systems are working and that health officials are identifying sick people quickly.

The Bottom Line

Everything we know so far points to the following: The Andes virus can lead to serious and potentially fatal outcomes in humans, but it is rarely transmitted from one person to another. Person-to-person transmission requires extended intimate contact with an infected individual.

Therefore, the risk of a new global pandemic and threat to the public at large remains low. Health officials are closely monitoring the situation, and the passengers who were exposed are receiving proper care. While it is always wise to stay informed about health threats, there is no reason for the general public to panic about this outbreak.

As with any health concern, the best approach is to rely on credible sources like the World Health Organization, the Centers for Disease Control and Prevention, and your local health department for accurate, up-to-date information.

Source: Healthline