Hantavirus, a rare disease usually caused by exposure to the urine or feces of infected rodents, is suspected to have killed three people after spreading on a cruise ship in the Atlantic Ocean.
According to the World Health Organization (WHO), two hantavirus cases have been confirmed, while five more suspected cases are under investigation. The ship was traveling from Argentina to Cape Verde, a group of islands off the coast of West Africa.
At first, hantavirus may feel like the flu, with patients suffering from fatigue, fever, chills, and aches. But over time, as the virus damages the heart, lungs or kidneys, patients can develop severe shortness of breath, organ failure and even death.
WHO said on Monday there was no need for alarm and the risk to the wider public was low. Yet experts are puzzled as to how the disease might have spread on a cruise ship.
Here’s what to know about hantavirus.
Hantavirus refers to a type of virus spread by rodents through their bodily fluids and excrement.
Humans often become infected when they ingest particles from dried rodent feces. Typically, this happens when someone attempts to dispose of rodent feces by sweeping it away, causing the particles to become dispersed into the air. The most common hantavirus in the United States is spread by deer mice.
Humans can also become infected by touching contaminated objects and then touching their mouth or nose. Hantavirus can also be spread through rodent bites or scratches, although this is rare.
Only one hantavirus – the Andes strain, which is native to South America – is known to spread from person to person, and it is rare.
However, some human-to-human transmission is suspected in this hantavirus outbreak, WHO said on Tuesday.
“We know that in some cases there was very close contact with each other and certainly human-to-human transmission cannot be ruled out, so that is what we are assuming as a precaution,” Dr. Maria Van Kerhove, WHO’s director of epidemiology and pandemic preparedness and prevention, told reporters.
Hantavirus causes two types of serious illness.
Hantaviruses found in Europe and Asia can cause hemorrhagic fever with renal syndrome (HFRS), which affects the kidneys. What starts with headache, stomach pain and nausea can develop into low blood pressure, internal bleeding and acute kidney failure. According to the US Centers for Disease Control and Prevention, 5–15% of cases are fatal, and symptoms usually take one to two weeks to develop after exposure.
Hantaviruses found in the Americas cause Hantavirus Pulmonary Syndrome (HPS). This disease affecting the lungs also causes flu-like symptoms in the beginning. But over time, some patients may experience shortness of breath and chest tightness as the lungs fill with fluid. After exposure, it may take one to eight weeks for symptoms to develop. The CDC said that about 40% of people who develop respiratory symptoms may die from HPS.
According to the CDC, there is no specific treatment for hantavirus. Patients can be treated with hydration, rest, and specific symptoms.
For this reason, prevention is important. The CDC says the best way to protect yourself from hantavirus is to keep rodents out of your home — sealing any gaps or holes in your home, sealing food properly, and putting garbage in thick containers with tight lids.
When cleaning up rodent droppings, use gloves, spray the waste with a bleach solution and wait five minutes before wiping the area with a paper towel and disposing of them safely.
According to a 2024 study, there are an estimated 60,000 to 100,000 cases of HFRS each year worldwide, with about half of the cases occurring in China.
CDC data shows that from 1993 to 2023, there were 890 cases of hantavirus disease in the US, most of which were in western states.
Interest in this little-known disease increased last year after Betsy Arakawa, wife of Oscar-winning actor Gene Hackman, died from HPS at age 65. Local public health records obtained by CNN revealed that dead rodents and rodent nests were found in several different buildings on the couple’s property in New Mexico.
Arakawa is believed to have died about a week before her husband, who was in the advanced stages of Alzheimer’s disease.
We don’t know yet. Dr. Charlotte Hamer, an assistant professor and epidemiologist at the University of Cambridge, said there were several possible scenarios.
“It’s not entirely unusual for rodents to hitch a ride on a ship, which could be a possibility,” Hammer said.
Because the disease has an incubation period of one to eight weeks, it’s also possible that people may have been infected when the ship last made port in Argentina, Hammer said. Another possibility would be “human-to-human transmission”, which he said would be “very unlikely” on this scale.
To find out how the disease spread on the ship, Dr. Scott Miscovich, a family physician and president and CEO of Premier Medical Group, said the ship needed to be “cultured to the maximum,” referring to the process of incubating viruses to identify them.
“All the droplets in every room, all the dust, all the kitchens, all the ventilation systems need to be sampled and then cultured,” he said.
The World Health Organization said a detailed investigation is underway, including sequencing of the virus to determine which strain infected the passengers.
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