What to know about hantavirus after cruise ship outbreak

Reports of a hantavirus cluster linked to a cruise ship in the Atlantic have led many travelers, especially in Florida, to wonder: Is it safe to travel?

Public Health experts say the answer is yes. While risk is currently low, understanding the situation can help put the outbreak into perspective.

What is hantavirus?

Hantavirus is not new, but it is uncommon. It is primarily a rodent-borne virus, meaning people are typically exposed through environments where infected rodents have left behind urine, droppings or saliva.

While rare in humans, hantavirus can lead to serious illness. Infection can cause hantavirus cardiopulmonary syndrome, a severe respiratory illness with a case fatality rate up to 50% in the Americas, according to the World Health Organization.

In the recent cruise ship outbreak, health officials have reported a small number of severe cases, including fatalities. Early findings suggest that exposure may have occurred before passengers boarded the ship, although investigations are ongoing.

"This is a rare event, and it's important not to overgeneralize the risk," said Sten Vermund, MD, PhD, dean of the USF Health College of Public Health and chief medical officer of the Global Virus Network, whose international headquarters are based at USF. "Hantavirus infections are typically linked to environmental exposure, not routine person-to-person spread or travel settings like cruise ships. In fact, this is the first-ever hantavirus outbreak on a cruise ship, and we still do not know whether there were unique circumstances. Investigations are ongoing. When complete, we can advise the industry on prevention."

How hantavirus spreads

Unlike viruses such as COVID-19 or influenza, hantavirus is not easily transmitted between people. Most infections occur when people breathe in dust from areas where rodents have been present.

The recent cases have been linked to the Andes strain of hantavirus, the only type known to spread between people. Health officials are continuing to investigate whether any transmission occurred onboard, as this type of spread is rare and typically requires close, prolonged contact.

Symptoms to watch for

Early symptoms of hantavirus infection can resemble the flu and may include:

• Fever
• Fatigue
• Muscle aches
• Headache or gastrointestinal symptoms such as nausea, vomiting or abdominal pain

In serious cases, symptoms can progress to:

• Shortness of breath
• Severe respiratory distress
• While the illness can be serious, it is also rare, and early medical care improves outcomes.

What this means for cruise travel

Florida is one of the world's largest cruise hubs, with millions of passengers traveling each year. But this incident does not indicate a broader risk to cruise travelers.

"Cruise ships have strong health and sanitation protocols, and there is no evidence that being on a typical cruise increases the risk of hantavirus," Dr. Vermund said. "This hantavirus outbreak is a unique event, but we want to ensure that future cruise ship travel is as safe as possible. The industry already takes rodent control very seriously, which may help explain why outbreaks like this have not been seen previously."

He added that cruise operators also have extensive experience managing the risk of person-to-person spread with more common infectious diseases, including norovirus, influenza and COVID-19.

Simple steps to stay safe

For most travelers, prevention is straightforward:

• Avoid contact with areas where rodents may be present
• Practice good hand hygiene
• Seek medical attention if symptoms develop after potential exposure

A reminder about emerging infections

While this outbreak is limited, it highlights a broader reality. Viruses can emerge in unexpected places.

As global travel increases, so does the importance of:

• Early detection
• Public health preparedness
• Clear, science-based communication

"This is a good example of the continued value of public health surveillance and research," Dr. Vermund said. "The goal is to ensure we are ready to respond quickly and effectively when unusual events occur."

Bottom line

The risk to most travelers appears low. Hantavirus is usually linked with exposure to infected rodents and rarely spreads between people. The situation is unusual and worth monitoring, but not a reason to cancel cruise or other travel plans. Anyone who develops flu-like symptoms after possible rodent exposure should seek medical care.