Andes Hantavirus Spread Raises Questions After Cruise Outbreak

Health officials are closely monitoring the spread of the Hantavirus Pulmonary Syndrome after at least 11 passengers connected to the MV Hondius cruise ship were reported to have contracted the Andes strain of hantavirus.

The outbreak has renewed concerns among scientists because the Andes strain is the only known hantavirus capable of spreading from person to person.

Three passengers linked to the outbreak have died so far.

Experts say the virus does not spread easily

For years, researchers believed the virus spread only after prolonged close contact with someone already showing symptoms.

Now, some experts are questioning whether transmission may occur more easily in confined settings.

Dr. Ashish Jha of Harvard Kennedy School said reports from doctors aboard the ship suggest several infections may have occurred without the type of extended exposure traditionally associated with transmission.

Still, officials from Centers for Disease Control and Prevention stressed that the overall public risk remains very low.

Why cruise ships create higher infection risks

Cruise ships are especially vulnerable to outbreaks because passengers share:

• Dining areas
• Cabins
• Elevators
• Common spaces
• Long periods in close proximity

CDC officials said those conditions likely played a major role aboard the Hondius.

Unlike viruses such as COVID-19 or influenza, however, Andes hantavirus is not considered highly contagious.

How Andes hantavirus spreads

Most hantavirus infections happen after exposure to infected rodent urine, saliva or droppings.

Human-to-human transmission appears to be rare and limited mainly to:

• Household contacts
• Romantic partners
• People sharing beds or utensils
• Exposure to bodily fluids

The CDC currently considers close exposure roughly equivalent to:

• Being within 6 feet
• For at least 15 minutes
• Near a symptomatic person

However, researchers acknowledge the science remains incomplete.

Researchers studying possible “superspreader” patterns

Scientists often point to a major outbreak in Argentina between 2018 and 2019.

During that outbreak:

• 34 people became infected
• 11 people died

Investigators concluded one infected individual likely spread the virus during crowded social events, including a birthday party.

In some cases:

• Transmission may have occurred from only brief encounters
• One infection possibly happened after a short greeting exchange

Those findings are now drawing renewed attention amid the cruise outbreak.

Can people spread the virus before symptoms appear?

So far, there is no confirmed evidence that asymptomatic people can transmit the Andes strain.

Still, infectious disease specialists caution that researchers lack enough data to rule it out completely.

One challenge is that hantavirus patients are usually identified only after becoming seriously ill, meaning mild or unnoticed infections may go undocumented.

Why hantavirus is so dangerous

Unlike flu viruses, hantavirus tends to settle deep inside the lungs rather than the nose or throat.

That limits its ability to spread widely but also makes infections more severe.

The virus can inflame blood vessels and rapidly impair breathing.

According to the CDC, fatality rates for hantavirus pulmonary syndrome can reach nearly 40% to 50%.

Currently:

• No vaccine exists
• No specific antiviral treatment is available
• Early intensive medical care offers the best chance of survival

Officials continue monitoring passengers

Passengers from the Hondius outbreak are currently under monitoring and quarantine in several countries, including:

• The United States
• Spain
• France
• The Netherlands
• The United Kingdom

Health authorities continue emphasizing that the outbreak does not resemble an airborne pandemic.

“This is not a virus that spreads like flu or Covid,” WHO officials previously said during the investigation.