A suspected hantavirus outbreak aboard a cruise ship has resulted in three fatalities and several other passengers falling ill. The World Health Organization (WHO) has confirmed that detailed investigations are currently underway, including extensive laboratory testing and epidemiological studies to determine how the virus is spreading. Sequencing of the virus from the current outbreak is also ongoing.
What is Hantavirus?
Hantaviruses are a family of viruses that have been present for centuries, with a documented history of outbreaks across Asia and Europe. In the Eastern Hemisphere, these viruses are associated with severe conditions such as haemorrhagic fever and kidney failure. A distinct group of hantaviruses emerged in the early 1990s in the southwestern United States, leading to the acute respiratory disease now known as hantavirus pulmonary syndrome (HPS). The disease gained significant attention in 2025 following the death of Betsy Arakawa, wife of actor Gene Hackman, from a hantavirus infection in New Mexico.
How Hantavirus Spreads
Hantavirus is primarily spread through contact with rodents or their urine, saliva, or droppings. The virus becomes particularly dangerous when contaminated material is disturbed and becomes airborne, posing a risk of inhalation. People are typically exposed to hantavirus around their homes, cabins, or sheds, especially when cleaning enclosed spaces with poor ventilation or entering areas with mouse droppings. The WHO notes that while rare, person-to-person transmission of hantaviruses may occur.
The US Centers for Disease Control and Prevention (CDC) began tracking the virus after a 1993 outbreak in the Four Corners region, where Arizona, Colorado, New Mexico, and Utah meet. Dr. Michelle Harkins, a pulmonologist at the University of New Mexico Health Sciences Center who has studied the disease for years, explained that a doctor with the Indian Health Service first noticed a pattern of deaths among young patients. Most US cases occur in Western states, with New Mexico and Arizona being hotspots, likely due to higher odds of mouse-human encounters in rural areas.
Symptoms of Hantavirus
An infection can progress rapidly and become life-threatening. Experts say symptoms often begin with a fever, chills, muscle aches, and possibly a headache. Dr. Sonja Bartolome of UT Southwestern Medical Center in Dallas noted that early symptoms can be indistinguishable from the flu. Symptoms of hantavirus pulmonary syndrome usually appear between one to eight weeks after contact with an infected rodent. As the infection progresses, patients may experience chest tightness as the lungs fill with fluid. The other syndrome caused by hantavirus—hemorrhagic fever with renal syndrome—typically develops within a week or two after exposure.
Death rates vary depending on the specific hantavirus. Hantavirus pulmonary syndrome is fatal in nearly 40% of infected individuals, while the death rate for hemorrhagic fever with renal syndrome ranges from 1% to 15% of patients, according to the CDC.
How to Prevent Hantavirus
There is no specific treatment or cure for hantavirus, but early medical attention can increase the chance of survival. Despite years of research, Dr. Harkins says many questions remain unanswered, including why the disease can be mild for some and severe for others, and how antibodies develop. She and other researchers have been following patients over long periods in hopes of finding a treatment. The best way to avoid the virus is to minimize contact with rodents and their droppings. Use protective gloves and a bleach solution for cleaning up rodent droppings. Public health experts caution against sweeping or vacuuming, as these actions can cause the virus to become airborne.
