Hantavirus outbreak unusual but risk to public is low
WHAT IS HANTAVIRUS?
Hantaviruses are rodent-borne viruses that can infect humans and cause diseases. The World Health Organization estimates that there are 10,000 to 100,000 human cases worldwide each year, and severity varies by type.
HOW DOES THE VIRUS SPREAD?
Hantavirus spreads primarily through rodents and is transmitted to humans through contact with rats or mice or through their urine, feces, or saliva; usually when the virus becomes airborne during cleaning of infested areas. Less commonly, it spreads from contaminated surfaces.
The Andean strain of hantavirus, found mostly in Argentina and Chile, is the only type of virus known to spread from person to person through close, prolonged contact. WHO confirmed on Wednesday that the outbreak on the cruise ship was Andean hantavirus.
WHAT ARE THE SYMPTOMS OF INFECTION?
Hantaviruses common in different parts of the world cause different symptoms or diseases, and some cause neither.
Symptoms usually begin one to eight weeks after exposure and can include fever, muscle aches and gastrointestinal problems, according to the World Health Organization.
In Europe and Asia, hantaviruses are known to cause hemorrhagic fever with renal syndrome, which mainly affects the kidneys and blood vessels.
In the United States, infection can cause hantavirus cardiopulmonary syndrome, which progresses rapidly and causes fluid accumulation in the lungs with cardiac complications.
The World Health Organization says death rates from hantavirus cardiopulmonary syndrome are as high as 50 percent, compared with one to 15 percent for infections common in Asia and Europe.
There is no specific treatment for hantavirus infection, so current treatment focuses on supportive care, including rest and hydration.
Patients may need breathing support such as a ventilator.
Prevention focuses on limiting contact with rodents through measures such as keeping areas and surfaces clean.
Contact tracing during outbreaks can improve outcomes and prevent further spread by allowing people potentially exposed to the virus to access hospital care sooner.
WHAT ARE THE RISKS FOR THE GENERAL PUBLIC?
WHO says the cruise ship outbreak is unusual and is being investigated by WHO and experts in several countries, but the risk to the public is low.
More generally, the WHO’s American branch warned in December that hantavirus infections were increasing in the region, particularly in Bolivia and Paraguay. An increase in death rates was also seen in Brazil and Argentina, where the most cases were seen.
Argentina reports 21 deaths in 2025; Among 66 people who contracted hantavirus pulmonary syndrome, the mortality rate was 32 percent; The average over the last four years was 15 percent.
